1-01
Nanostructured Materials Based on Polyelectrolyte Complexes
MARTIEN COHEN STUART, Laboratory of Physical Chemistry and Colloid Science,
Wageningen University, Dreijenplein 6, 6703 HB, Wageningen, The Netherlands,
martien.cohenstuart@wur.nl
Self-assembly processes in water are often driven by hydrophobic attraction; well known
examples are common surfactant micelles and lipid bilayer vesicles. Other binding mechanisms
can be very relevant, too, like metal coordination or electrostatic interaction. We discuss in this
contribution polymer micelles consisting of oppositely charged polyelectrolytes, at least one of
which is a diblock copolymer with a neutral, water soluble block. The core of these micelles
consists of an insoluble complex coacervate formed by the ionic chains, and a corona made up of
the neutral hydrophilic chains. Typical features of these micelles are that they (i) are formed only
within a window of compositions around charge stoichiometry, and (ii) that they are fully
reversible with respect to changes in polymer composition, pH and ionic strength in the solution.
We have characterized micelles of this kind with a variety of techniques and using various
polymers. In addition, we have studied their behaviour on solid surfaces.
1-02
Multifunctional and Responsive Behavior of ABC Terpolymers with Amphoteric Blocks
C. TSITSILIANIS 1, I . Katsampas1, Y. Roiter2, S. Minko2, 1Department of Chemical
Engineering, University of Patras 26504, Patras, Greece and Institute of Chemical Engineering
and High Temperature Chemical Processes, ICE-FORTH, 2Department of Chemistry, Clarkson
University, Potsdam, NY, ct@chemeng.upatras.gr
ABC block terpolymers constituted of three different polymer blocks demonstrate numerous
possibilities of self organization in the bulk, at interfaces and in solutions. This behavior has
attracted great interest and caused recent rapid development of the ABC block copolymer
synthesis and investigations. The ABC terpolymers exhibit a wide variety of tunable selfassembled morphologies with potential applications in nanotechnology and biomedicine. Here
we report on a double hydrophilic stimuli responsive ABC terpolymer poly(2-vinyl pyridine)-bpoly(acrylic acid)-b-poly(n-butyl methacrylate) (P2VP-PAA-PnBMA) which exhibits a rich
polymorphism and multifunctionality in aqueous media (multiple response). The properties of
the copolymer aqueous solutions depend strongly on pH. At low pH three-compartment spherical
micelles with positively charged outer corona are formed. The micelles are thermo-responsive
around the upper critical solution temperature (UCST) of the PAA blocks. As pH increases the
micelles are transformed to other micellar structures due to the progressive deprotonation of
P2VP blocks and the neutralization of PAA blocks. At pH 6 a three-dimensional physical
network is formed constituted of hydrophobic domains of P2VP and/or PnBMA blocks
interconnected by negatively charged bridging PAA blocks. This physical hydrogel is sensitive
to ionic strength which induces a closed loop Sol-Gel-Sol transition. The so formed gel exhibits
the characteristic behavior of Telechelic Associative Polyelectrolytes [Macromolecules, 2005,
38, 1307].
1-03
Design of Self Assembled Surfactant Nanostructures at Interfaces: Effects of Regioisomeric and Stereo-isomeric Chemical Structure Changes
RAMESH VARADARAJ, ExxonMobil Research and Engineering Company, Annandale, NJ,
ramesh.varadaraj@exxonmobil.com
The influence of regio-isomeric and stereo-isomeric changes in surfactant chemical structure on
interfacial properties was studied using two sets of alkyl aromatic sulfonate surfactants . Two
regio-isomeric sodium n-dodecyl xylene sulfonates : ortho and para isomers, and two stereoisomeric sodium n-decyl stilbene sulfonates: dl and meso isomers were synthesized and their
interfacial properties determined at the air-water, hydrocarbon-water and solid-water interfaces.
For the regio-isomeric xylene sulfonates, the para-isomer exhibited a lower critical aggregation
concentration and higher efficiency of interfacial tension reduction at the air-water, decane-water
and solid -water interfaces. The dynamic interfacial properties i.e., rate of interfacial tension
reduction and dynamic wetting were higher for the ortho isomer compared to the para isomer.
Differences in molecular packing of the para isomer compared to the ortho isomer is key to
account for the observed differences in interfacial properties. For the stereo-isomeric stilbene
sulfonates, while the interfacial properties were not significantly different in water, in 0.1N NaCl
solution differences in properties between the meso and dl isomers were observed. The meso
isomer exhibited a lower critical aggregation concentration and higher efficiency of interfacial
tension reduction at the air-water and decane-water interfaces. The dl isomer exhibited a higher
rate of surface tension reduction at the air-water interface and marginally better dynamic wetting
properties at the Teflon-water and Parafilm-water interfaces. Alteration of molecular packing at
the interface accounts for these observations. This study demonstrates how subtle differences in
molecular packing at interfaces due to regiochemical and stereochemical structural changes can
impart significant interfacial property changes in self-assembling molecules. These findings
impact the design of self-assembled surfactant nanostructures at interfaces and control of
performance attributes such as foaming, emulsification and surface wetting.
1-04
Self-recognising Fluid Monolayers of DNA-based Surfactants: Properties and Applications
VESSELIN N. PAUNOV, Chun Xu, Pietro Taylor, Paul D. I. Fletcher, Surfactant & Colloid
Group, Department of Chemistry, University of Hull, Hull, UK, V.N.Paunov@hull.ac.uk
We have designed novel DNA-surfactants prepared by covalent attachment of a hydrophobic
anchoring group to the (3’- or 5’-) end of short DNA oligonucleotides. This anchoring group
turns these DNA-strands into amphiphilic molecules. Such DNA-surfactants can adsorb at airwater and oil-water surfaces which orients them with respect to the liquid surface and can
promote programmable interaction based on Watson-Crick pairing. We show that these materials
are surface-active at various fluid surfaces, including air-water and oil-water interfaces, as well
as lipid bilayers. We demonstrate that once adsorbed the DNA-surfactants used remain on the
liquid surface upon hybridisation with a complementary DNA chain. Complementary DNAsurfactants are used to functionalise fluid surfaces and to program the interactions between them
based on Watson-Crick pairing. By selecting the appropriate DNA base sequences the interaction
between the fluid surfaces functionalised with DNA-surfactants can be programmed with the
level of specificity as the enzyme-substrate interaction. We studied the adsorption of DNA
surfactants at the oil-water interface by Drop Shape Analysis and demonstrated that the
interfacial tension isotherm at the oil-water interface depends strongly on the number of bases as
well as the base sequence in the DNA surfactant. DNA hybridization at the oil/water interface
was studied by measuring the interfacial tension of DNA surfactant during temperature jump
across the melting point of complementary DNA-surfactants. Complementary sequences and non
complementary sequence of DNA surfactant show clear difference during the temperature jump
process. We also found that DNA surfactants can be immobilised on hydrophobic solid surfaces
by hydrophobic interactions which allowed us to design a novel method for fabrication of DNA
arrays based on microcontact printing of aqueous ‘‘inks’’ containing DNA surfactants on solid
substrates. Novel type of aqueous inks based on DNA-functionalised small liposomes for
micropatterning of solid surfaces with DNA by a microcontact printing technique has been used.
We illustrate the capabilities of this technique by specific deposition of complementary DNAfunctionalised liposomes onto DNA-micropatterned solid surfaces. Special attention is paid to
the wetting properties of the ink with respect to the stamp and the solid substrates. The method
allows for efficient attachment of DNA strands to solid surfaces and hybridisation with
complementary fluorescently-tagged oligonucleotides. This new technology could be utilised for
rapid preparation of DNA-assays and genetic biochips.
1-05
Triggered Morphological Transformations in Block Copolymer Aggregates in Solution
S. Burke, A. Choucair, F. Liu, L. Luo, H. Shen, A. EISENBERG, Department of Chemistry,
McGill University, 801 Sherbrooke Str. West, Montreal, QC, Canada, adi.eisenberg@mcgill.ca
Ever since it was shown that block copolymer micelles can self-assemble in solution to give
aggregates of a wide range of morphologies, interest in applications of such structures has grown
considerably. For some applications, e.g. delivery of specific agents out of vesicles, it is useful to
understand the factors which trigger morphological changes, as well as the mechanisms of such
changes. In this presentation, several such mechanisms are reviewed, i.e. rod-to-vesicle and
sphere-to-rod as well as the reverse transitions, in addition to the mechanism of size changes in
vesicles. All these transitions can be induced, in the vicinity of phase boundaries, by small
changes in one of the “morphogenic” factors, most conveniently the composition of the solvent.
The rod-to-vesicle transition involves a progressive flattening and shortening of the rod, with a
simultaneous generation of curvature in the flattened part (to a structure resembling a Chinese
wok), the enlargement of the curved or bowl-like section at the expense of the rod, and finally
closure of the bowl. Easily accessible relaxation times are of the order of tens to hundreds of
seconds. The reverse transition involves a very rapid collapse of the vesicle. The sphere to rod
transition involves initially the formation of a “bead necklace” like structure, and subsequent
smoothing of the bumps, while the reverse transition involves bulb formation and the splittingoff of spherical micelles from the ends. Finally, vesicle enlargement involves contact and
adhesion, coalescence and formation of a center wall, destabilization of the wall, asymmetric
detachment of the wall at some point, retraction into the outer wall, and smoothing into a
spherical shape. Vesicle fission involves elongation, internal waist formation, narrowing of the
external waist, and complete separation. The mechanisms are reminiscent of some biological
processes, and are usually subject to two relaxation times.
1-06
Synthesis and Self-organization of Multiple Stimuli Responsive Amphiphilic Polymers in
Aqueous Media
A. LASCHEWSKY, S. Garnier, M. Mertoglu, K. Skrabania, J. Storsberg, University of Potsdam,
Germany, and Fraunhofer Institute for Polymer Research, D-14476 Potsdam-Golm, Germany,
laschews@rz.uni-potsdam.de
Amphiphilic block copolymers undergo efficient self-organization in bulk and in solution. They
form supramolecular aggregates, in particular in aqueous solution. In order to develop dynamic
systems instead of purely static ones where the properties are defined once forever by the
chemical structure, stimuli-sensitive polymers have been developed. They are generally aimed at
changing the character of functional groups reversibly from hydrophilic to hydrophobic, or vice
versa, in order to switch the system between an amphiphilic and non-amphiphilic state. In this
context, a series of water-soluble AB-diblock and ABC-triblock polymers was synthesized by us
via reversible addition fragmentation chain transfer polymerization (RAFT). This method is a
powerful method to prepare functional polymers of complex structure. The new block
copolymers were investigated concerning their aggregation in water, in dependence on external
stimuli. In particular, the possibility of multiple switchable systems is explored for copolymers
containing two stimuli-sensitive hydrophilic blocks. Orthogonal switching the hydrophilicity of a
single or of several blocks by changing the pH, the temperature or the salt content demonstrates
the variability of the various molecular designs, and exemplifies the concept of multiplesensitive systems.
1-07
Nanostructured Materials Formulation and Synthesis via Self-Assembly and Directed
Assembly of Amphiphilic Block Copolymers
P. ALEXANDRIDIS, Department of Chemical and Biological Engineering, University at
Buffalo, The State University of New York, Buffalo, NY, palexand@eng.buffalo.edu
The interplay between (a) self-assembly properties of amphiphilic block copolymers (ABCs) and
(b) synthesis and colloidal stabilization of nanoparticles (NPs) in liquid media containing ABCs
is a central theme in our research. When dissolved in selective solvent, ABCs can provide
nanoscale environments of varying and tunable dimensions and shape, local polarity,
concentration, mobility, affinity to surfaces, and reactivity [Macromolecules 1995, 28, 8604;
1998, 31, 6935; 2000, 33, 5574; 2001, 34, 5979; 2002, 35, 4064; 2004, 37, 912]. ABCs can thus
initiate NP formation, facilitate NP growth, control NP size and shape, modify NP surfaces for
dispersibility in solution or a solid matrix, alter NP optical and electronic properties, and promote
long-range NP organization. The relationship between ABC characteristics and NP structure is
beneficial for several applications. Examples will be presented from our work on ABCstructured pharmaceutical and coating formulations [J. Colloid Interface Sci. 2002, 252, 226;
2002, 255, 1; J. Phys. Chem. B 2002, 106, 10834], and ABC-templated synthesis of metal
nanoparticles [Langmuir 2004, 20, 8426; J. Phys. Chem. B 2005, 109, jp046221z;
Nanotechnology 2005, 16, S344].
1-08
Ordering and Interactions in Electrorheological fluids
J. PERSELLO1, B. Cabane2, G. Bossis3, R. Schweins4, 1LCMI, Université de Franche-Comté, 16
route de Gray; 25030 Besançon, France, 2PMMH, CNRS UMR 7636, ESPCI, 10 rue Vauquelin,
75231 Paris cedex 05, France, 3LPMC, Université de Nice, Parc Valrose, 06108 Nice Cedex 2,
France, 4ILL, BP 156, 38042 Grenoble cedex 9, France, jacques.persello@univ-fcomte.fr
Some fluids can respond to an applied electric fluid, switching from a disordered structure with a
fluid-like response to an ordered structure with a solid-like response. More research on these
fluids is performed in order to use them as hydraulic actuators in micro-devices or as electrooptical devices, e.g. sensors, switches, narrow-band filters, and wave guides. A critical feature in
the performance of such fluids is the control of interparticle interactions. Indeed, the particles
must repel each other at short distances, otherwise the field-induced aggregation is not fully
reversible and the device cannot be switched repeatedly. In the present work, we combine
numerical calculation and Small-Angle Neutron Scattering experiments to study the phase
transitions in the structure of a fluid made of surface modified silica particles dispersed in
silicone oil. We shall be using the Neutron small angle scattering instrument as a Surface Force
Apparatus. When an electrical field was applied, a two-dimensional set of diffraction spots was
obtained, located in the direction of chain alignment. The spacing of these diffraction spots
yields the average interparticle distance, which is found to vary, from a complex way, with the
electrical field, the field frequency and the surface chemistry of the silica particles.
1-09
Nanostructured, Smart Hydrogel Layers
DIRK KUCKLING, Katja Kretschmer, Cathrin Corten, Pradeep Pareek, Institut für
Makromolekulare Chemie und Textilchemie, TU Dresden, D-01062 Dresden, Germany,
dirk.kuckling@chemie.tu-dresden.de
Photo cross-linkable hydrogels are of considerable interest as materials in microsystems (e. g.
microactuators) and biotechnology, in which the gel sizes are reduced to the µm-range (gel
thickness and gel extension). Both temperature and pH-responsive hydrogels have been applied
for flow control in microfluidic devices requiring no external power supply. However,
controlling interactions of hydrogels with biomolecules is still a challenge. For this purpose
hydrogel layer assemblies have been investigated.
Novel PNIPAAm block copolymers have been prepared by using controlled radical
polymerization. Due to the radical character of the polymerization a random copolymer block of
NIPAAm and a chromphore could be attached to the macroinitiator. The volume phase transition
of constrained hydrogel layers was studied by a combination of surface plasmon resonance
(SPR) spectroscopy and optical waveguide spectroscopy (OWS) as a function of cross-linking
density, and composition. This technique has been applied previously for random copolymers,
and is now extended to photo cross-linkable block copolymers and hydrogel layer assemblies.
The swelling behavior was affected by the macroinitiator content as well as the cross-linking
density of the PNIPAAm phase.
1-10
Nanofabrication via Block Copolymer Templates: From Nanoparticle Arrays to Optical
Waveguides
D. H. KIM, Xue Li, King Hang Aaron Lau, Thomas. P. Russell, Jin Kon Kim, W. Knoll, Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany,
kimdh@mpip-mainz.mpg.de
We present latest developments on the use of self-assembled block copolymer (BCP) thin films
as templates and scaffolds for nanostructured materials. First, various simple routes to fabricate
hexagonally patterned nanoparticle arrays are discussed. Asymmetric diblock copolymers of
poly(styrene-co-ethylene oxide) (PS-b-PEO), poly(styrene-co-2-vinyl pyridine) (PS-b-P2VP),
poly(styrene-co-methyl methacrylate) (PS-b-PMMA) with cylindrical microdomains were
employed to generate arrays of gold (Au), titania (TiO2), and composite Au/TiO2 by chemical
vapor deposition and sol-gel process, and photophysical properties of the resulting hybrid
nanostructures are discussed. Second, the potential application of block copolymer thin films as
planar optical waveguides is considered. PS-b-PMMA thin films with cylindrical PMMA
microdomains oriented normal to the substrate surface were used to couple optical modes in the
Kretschmann configuration and their waveguiding properties are investigated. The methodology
provides a significant advance over other conventional analytical tools to monitor the
nanofabrication processes occurring in the BCPs in terms of the simplicity and high-sensitivity.
1-11
Nanomolecular Valve Effect of Cu Complex Crystal in Gas Adsorption
Hiroshi Noguchi1, Atsushi Kondo1, Hiroshi Kajiro2, Yoshiyuki Hattori3, HIROFUMI KANOH1,
Katsumi Kaneko1, 1Chiba University, 1-33 Yayoi-cho, Inage, Chiba, Japan, 2Nippon Steel
Corporation, Futtsu, Japan, 3IRI, Takada, Kashiwa, Japan, kanoh@pchem2.s.chiba-u.ac.jp
Adsorption of supercritical gases such as H2, or CH4 on microporus solids has gathered much
attention with respect to energy or environmental technologies. A microporous metal organic
solid has a great advantage for designing and construction of the porous framework appropriate
for selective adsorption of the target molecules. Although general metal organic solids available
for adsorption have open channels in the crystals, Cu complex-assembled microcrystal
[Cu(bpy)(BF4)2(H2O)2(bpy)]n (bpy = 4,4’-bipyridine) has no open channels. However, Li and
Kaneko found a remarkably specific adsorption behavior of high reproducibility for CO 2 in Cu
complex-assembled microcrystal [Cu(bpy)(BF4)2(H2O)2(bpy)]n (bpy = 4,4’-bipyridine)
irrespective of no open channels. Thus, this Cu complex solid is denoted a latent porous copper
crystal (LPC). CO2 is vertically adsorbed and desorbed at specific pressures at 273K. The
mechanism of such a nanomolecular valve effect has not been clear because the crystal structure
was not understood after pretreatment for removal of water molecules from LPC. Recently we
have constructed a model structure of LPC from the experimental data from in-situ FTIR,
elementary analysis, TG, XRD, and so on. In the present paper, the mechanism of the
nanomolecular valve effect will be presented based on the model structure.
1-12
Microcalorimetry and Scattering in Binary and Ternary PNIPA Systems near the Volume
Phase Transition
K. LASZLO1, K. Kosik1, E. Wilk1, E. Geissler2, 1Department of Physical Chemistry, Budapest
University of Technology and Economics, Budapest 1521, Hungary, 2Laboratoire de
Spectrométrie Physique CNRS UMR5588, Université J. Fourier de Grenoble, B.P.87, 38402 St
Martin d'Hères cedex, France, klaszlo@mail.bme.hu
Poly(N-isopropylacrylamide) gels swollen in pure water exhibit a volume phase transition (VPT)
at 34ºC, above which the solvent is expelled. Data from isothermal and scanning
microcalorimetry and small angle X-ray scattering (SAXS) observations confirmed that the gel
collapse involves two stages. The first is prompt microphase separation in which the polymer
chains form a foam-like structure: water bubbles several hundred nm in diameter are separated
by 10 nm thick polymer film clusters. The second stage involves slow relaxation, with a mutual
diffusion coefficient of about 10-17 cm2/s, characteristic of glassy materials. In contact with
aqueous phenol solutions, these gels display a VPT already at 20 C at aromatic acid
concentrations that depend on the number of OH-substitutions. Dynamic light scattering
measurements, in which light from the thermodynamic fluctuations is heterodyned by that from
the large-scale network heterogeneities, show that DcRdyn/ (Dc and Rdyn are the collective
diffusion coefficient and the Rayleigh ratio, respectively,  is the polymer volume fraction) is
independent of the aromatic concentration. Thus, the friction coefficient of the polymer chains is
not modified in the presence of the binary solvent and below the VPT concentration the phenols
are not directly in contact with the polymer chain.
1-13
A Novel Method for Controlling the Size and Spatial Patterning of Defect Domains in a
Smectic A Liquid Crystal
S. SHOJAEIZADEH, S. L. Anna, Department of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, PA, shahab@cmu.edu
Controlling the size and spatial ordering of defects in liquid crystals offers new possibilities for
exploiting their unique optical and rheological properties. Recently, confinement of liquid
crystals in silicon microchannels has been shown to create ordered defect patterns [PNAS, 2004,
101, 17340]. However, silicon micromachining is costly and time consuming. We present an
alternate, rapid, and inexpensive method for controlling defect patterns in smectic liquid crystals
on PDMS films. We first show that as-prepared and PEI coated PDMS films impose
homeotropic and planar boundary conditions, respectively. Next, by oxidizing a thin film of
PDMS in oxygen plasma, a thin glassy surface is created. Applying a uniaxial stress breaks this
glassy surface and creates microscale parallel cracks. A drop of smectic liquid crystal on the
surface exhibits ordered toroidal defects between two crack lines. The distance between two
adjacent cracks dictates the size of defects. Sandwiching liquid crystal between two parallel
plates in which one surface is cracked shows that up to a certain gap thickness, cracks are still
capable of controlling the size and order of defects.
1-14
Pore Expansion in Fluorinated Surfactant Templated Porous Silica Thin Films through
Supercritical Carbon Dioxide Processing
KAUSTAV GHOSH1, Hans-Joachim Lehmler2, Stephen E. Rankin1, Barbara L. Knutson1,
1
Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson
Hall, Lexington, KY, 2Department of Occupational and Environmental Health, University of
Iowa, 100 Oakdale Campus #124 IREH, Iowa City, IA, kghos2@uky.edu
The effect of processing mesoporous silica thin films with supercritical CO2 immediately after
casting is investigated, with a goal of using the penetration of CO2 molecules in the tails of CO2philic cationic fluorinated surfactant templates to tailor the final pore size. Well-ordered thin
films with 2D hexagonal close-packed pore structure are synthesized through the liquid phase
co-assembly of a homologous series of perfluoroalkylpyridinium chloride surfactants and an
inorganic silica precursor. Hexagonal mesopore structures are obtained for both unprocessed
films and after processing the cast films in CO2 at constant pressure (69-172 bar) and
temperature (25oC to 45oC) for 72 hours, followed by surfactant extraction. XRD and TEM
analysis reveal controlled and significant increases in pore size for all CO2 treated thin films
relative to the unprocessed sample with increase of CO2 pressure. The degree of pore expansion
achieved is directly dependent on the length of the fluorinated tail throughout the homologous
series of surfactants. These results demonstrate that combining the tunable solvent strength of
compressed and supercritical CO2 with the ‘CO2-philic’ nature of fluorinated tails allows one to
control the pore size in ordered mesoporous silica thin films through CO2 processing.
1-15
Dynamic Manipulation of Proteins and Colloidal Scale Objects with Smart NanoTextured
Surfaces
A. Toscano, N. Kozlova, M. M. SANTORE, Department of Polymer Science and Engineering,
University of Massachusettes Amherst, 120 Governors Drive, Clarkson University, Amherst,
MA, santore@mail.pse.umass.edu
Using planar surfaces with 10-nm scale regions of controlled surface chemistry, we are able to
manipulate the adhesion dynamics of a variety of objects, ranging from small proteins (3-4 nm in
size) to micron-scale colloidal particles. The surfaces exert both selectivity and tunability in the
adhesion dynamics. The key to these behaviors is that the surface chemistries making up the
nanopatterns exert substantially different forces on the approaching objects / molecules, setting
up lateral competition between attractions and repulsions. In the case of protein adsorption, we
demonstrate the ability of small adhesive islands to capture individual fibrinogen molecules, or
to hold up to 4 lysozyme molecules in relatively close proximity. Surfaces of similar chemistry
are shown to give controlled adhesion rates of micron-scale colloidal particles, from a flowing
suspension. In the case of the colloidal particles, the adhesion rates depend on the spacing on the
attractive islands on the opposing surfaces. The observations suggest a dynamic patternrecognition mechanism where lengthscales set up by the particle and ionic strength (through
fluctuations) mate with those of the surface at the threshold conditions for adhesion.
1-16
Stimuli-Responsive Polymeric Films from Colloidal Dispersions
MAREK W. URBAN, NSF Materials Research Science and Engineering Center at USM, The
University of Southern Mississippi, Hattiesburg, MS, marek.urban@usm.edu
Colloidal dispersions have been of interest for a long time, and recent advances in phospholipid
(PL) chemistry combined with traditional monomer polymerization or crystallization in the
presence of PL resulted in the development of a new generation of colloidal films that exhibit
unique film formation properties. This presentation will focus on the developments of nonspherical colloidal particles and the effect of particle morphologies on film formation and
stratification near the film-air (F-A) and film-substrate (F-S) interfaces. Using biologically active
PLs it is possible to induce the formation of surface localized clusters (SLICs) that may serve as
rafts for other applications.
1-17
Stimuli-Responsive Layer-by-Layer Polymeric Films and Capsules
S. SUKHISHVILI, Department of Chemistry and Chemical Biology, Stevens Institute of
Technology, Hoboken, NJ, ssukhish@stevens.edu
We discuss the role of hydrogen bonding and electrostatic interactions in pH- and temperatureresponsive multilayer films and capsules, which contain a weak polyelectrolyte as one of the
multilayer components. We will contrast fundamental differences between electrostatic and
hydrogen bonding layer-by-layer polymer self-assembly, including charge regulation and charge
imbalance within the film. Along with the systems where hydrogen-bonded and electrostatically
adhered polymers are incorporated into different stacks of hybrid films, we introduce copolymers
that combine centers for electrostatic and hydrogen bonding in one molecule, such as
polybetaines containing carboxylate groups and quaternized derivatives of poly-4-vinylpyridine
with pyrrolidone moieties. Such copolymers can be self-assembled via electrostatic mechanism
at neutral pH values, but they also yield robust multilayers with polycarboxylic acids at low pH
in salt solutions where the films are stabilized by hydrogen bonding. Temperature responsiveness
can also be imparted to films by introducing poly(vinyl methyl ether). Strategies to stabilize
films at high pH values by introducing covalent cross-links will also be discussed. The
permeability of self-assembled layers and capsules to small molecules is strongly pH- and/or
temperature-dependent, showing potential for controlled release applications.
1-18
Patterning of Polymeric and Biomolecular Nanostructures: Approaches and Challenges
STEFAN ZAUSCHER, Department of Mechanical Engineering and Materials Science, Center
for Biologically Inspired Materials and Materials Systems, Duke University, 144 Hudson Hall,
Durham, NC, zauscher@duke.edu
Fabricating stimulus-responsive, smart polymeric and biomolecular structures on surfaces and
the control of their architecture on the nanometer length scale is important for applications in
biosensors, proteomic chips and nanofluidic devices. Here we present methods that we have
developed that allow for molecular-level control in the fabrication of polymeric and
biomolecular nanostructures. First we describe the fabrication and characterization of stimulus
responsive, elastin-like polypeptide (ELP) nanostructures grafted onto functionalized thiolates
patterned onto gold surfaces with dip-pen nanolithography (DPN). ELPs undergo a reversible,
hydrophilic-hydrophobic phase transition in response to external stimuli, such as a change in
temperature or ionic strength. This phase transition behavior was exploited to reversibly
immobilize a thioredoxin-ELP (Trx-ELP) fusion protein onto the ELP nanopattern above the
lower critical solution temperature (LCST) demonstrating the potential for ELP nanoarrays in
reusable lab-on-chip devices for protein purification or nanoscale analysis. Next we describe the
fabrication of stimulus-responsive, poly(N-isopropylacrylamide) (pNIPAAM) brush
nanopatterns in a “grafting-from” approach that combines scanning probe lithography and ebeam lift-off lithography, with surface initiated polymerization using atom transfer radical
polymerization (ATRP). We demonstrate the reversible, stimulus-responsive conformational
height change of these nanopatterned polymer brushes by inverse transition cycling in water, and
water-methanol mixtures. Our nanofabrication approaches are generic and can likely be extended
to a wide range of vinyl monomers. Finally we discuss surface-initiated ring-opening metathesis
polymerization (ROMP) of cyclic monomers on silicon oxide nanopatterns fabricated by atomic
force microscope (AFM) anodization lithography. The combination of anodization lithography
and surface-initiated ROMP allows us to fabricate small, nanoscale features on silicon surfaces
either by solution or vapor phase introduction of the monomer. We will describe our results
characterizing these sample surfaces using TappingMode and potential gradient AFM imaging.
1-19
Nanoscale Functionalization and Site-Specific Assembly of Colloids by Particle
Lithography
CHARLES E. SNYDER, Allison M. Yake, Jason D. Feick, Darrell Velegol, Department of
Chemical Engineering, The Pennsylvania State University, University Park, PA,
ces988@psu.edu
The production of a simple localized and nanoscale charge distribution on the surfaces of
individual colloidal microspheres is realized here using our technique of “particle lithography”.
In this technique, parts of the microspheres are masked off, while polyelectrolytes (or other
molecules) cover the remaining portions of the microspheres. The result is a microsphere with a
functionalized patch of controlled size. The effectiveness of this process is demonstrated by the
accurate and reproducible production of colloidal heterodoublets composed of oppositelycharged microspheres. The particle lithography technique is advantageous since it is not limited
by the resolution of photolithography or by functionalizing chemistries, and the technique opens
the door for complex site-specific functionalization of particles. The size of the functionalized
patch may be tailored through the use of polyelectrolytes (or any masking agents) of different
sizes, or by adjusting the salt concentration (i.e. adjusting the Debye layer thickness). The
particle lithography process and it’s degree of accuracy will be better understood through
modeling.
1-20
Xerogel from Silica and Naphthanediimide, an Efficient Photoredox Agent
Nelcy D. S. Mohallem1, MÁRIO J. POLITI2a, Magali A. Rodrigues2b, 1Departamento de
Química, ICEx, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-910, Belo
Horizonte, MG Brasil, 2Departamento de Bioquímica, Instituto de Química, Universidade de
São Paulo, P.O. Box 26077, 05513-970, São Paulo, SP, Brasil, amjpoliti@usp.br,
b
marodrig@icb.ufmg.br
A nanohybrid xerogel composed of N, N´-bis(2-phosphonoethyl)-1, 4, 5, 8-naphtalenodiimide
(DPN) with silica was obtained by doping the sol-gel with DPN during the TEOS condensation
reaction. Physical and chemical aspects of the xerogel were obtained by FTIR, TA and BET.
Morphological analyses reveal that DPN are located inside the particle pores. Photochemical
studies in the presence of Trpytophan (Trp) showed that the xerogel is efficiently promoting the
photosensitization of Trp radical formation. Photophysical studies demonstrated the presence of
J-aggregates of DPN. The splitting model of exciton theory was used to determine the distance
between DPN molecules (~7Å). The silica sterical hindrance and the DPN geometry inside the
silica particles are main factors for the good photosensitizing efficiency of the xerogel. Sponsors:
FAPESP, CNPQ and CAPES.
1-21
Synthesis and Rearrangement of Block Copolymer Brushes
WILLIAM J. BRITTAIN, Department of Polymer Science, The University of Akron, Akron,
OH, wjbritt@uakron.edu
The synthesis of tethered block copolymer brushes via the use of controlled/‘living’ free radical
polymerization techniques presents many significant advantages over traditional free radical
polymerization techniques. In our group, we have found that the most versatile
controlled/‘living’ free radical polymerization techniques are atom transfer radical
polymerization (ATRP) and reversible addition fragmentation transfer (RAFT) polymerization.
Both diblock and ABA type triblock copolymer brushes have been synthesized using either
ATRP or RAFT. Of particular interest with block copolymer brushes, are their ability to
reversibly rearrange upon treatment with selective solvents. This rearrangement of block
copolymer brushes can result in the formation of unusual surface morphologies that have been
attributed to the formation of either ‘pinned micelles’ or ‘folded’ structures. We have
demonstrated the other external stimuli besides block-selective solvents can be used to induce
brush reorganization such as temperature and treatment with supercritical CO2. We have
recently been studying the use of block rearrangement to control flow and permeability.
1-22
Ultrahydrophobic Surfaces through Surface-attached Ultrathin Polymer Films
J. S. D. Jeyaprakash Samuel; I. J. Park, J. RÜHE, Chemistry and Physics of Interfaces, Institute
for Microsystems Engineering (IMTEK), University of Freiburg, Georges Köhler-Allee 103,
D79110 Freiburg, Germany, ruehe@imtek.de
The leaf of the lotus plant has, like a variety of other plant surfaces, strongly ultrahydrophobic
surface properties due to a series of micro- and nanostructures spanning a wide spectrum of
length scales. Water cannot wet the surfaces, even upon impact, and rolls easily off the surface,
collecting dust and other particles along the way. The study of these unusual wetting properties
of such natural surfaces has suggested to introduce such a concept into a variety of different
engineering applications. The transfer of this concept into artificial materials, however, had only
somewhat limited success so far.
After having very good initial properties, the
ultra¬hydrophobicity of such surfaces usually deteriorates rather quickly. One of the major
problem has been that artificial surfaces, unlike plant surfaces, do not have a possibility to
regenerate after physical damage of the micro- or nanostructures and once the surface is
mechanically damaged, the surface properties are changed irreversibly. We present new
techniques to obtain ultrahydrophobic surfaces through a combination of surface-attachment of
fluorinated polymers and microstructure generation. The polymer molecules are either grown on
the surface of the substrate through surface-initiated polymerization or become attached through
a photochemical process.
1-23
Binary Polymer Brushes: Structured Surface with Reversiby Tunable Wetting Properties
MARCUS MUELLER, Department of Physics, University of Wisconsin-Madison, Madison, WI,
mueller@physics.wisc.edu
Grafting of two incompatible polymers onto a substrate one prevents macroscopic phase
separation and the laterally self-assembled thin film structures exhibit reversibly tunable wetting
properties. Self-consistent field calculations utilizing the Gaussian chain model and a virial
expansion for the interactions predict a rich phase diagram of laterally periodic morphologies as
a function of solvent quality, composition of the brush, incompatibility of the two polymer
species and grafting density, however, the structures observed in experiments lack long-range
periodic order. We employ Monte Carlo simulations of a coarse-grained off-lattice model to
investigate the influence of spatial correlations of the grafting points onto the morphology of
onecomponent brushes in a bad solvent and binary brushes. Comparing different selfassembled
structures on identical sets of grafting point we observe a pronounced correlation between the
average morphology of the brush and density fluctuations of the grafting points. These
fluctuations in the grafting points prevent long-range order. Rather than a sharp thermodynamic
transition, we observe a gradual building up of structure upon increasing the incompatibility and
the structure formation occurs at smaller incompatibility and the length scale is slightly larger
than in case of grafting on a regular lattice. Chain length polydispersity has only a much smaller
influence on the structure. Different morphologies as a function of composition give rise to very
similar structure factors but can be well distinguished by their Euler-characteristics.
1-24
Mixed Polyelectrolyte Brushes: Adaptive and Responsive Polymer Surfaces
M. STAMM1, N. Houbenov1, D. Usov2, S. Minko3, 1Leibniz Institute of Polymer Research
Dresden, Germany, 2University Ghent, Belgium, 3Clarkson University, Potsdam, NY,
stamm@ipfdd.de
We have shown in the past that different binary polymer brush layers at solid surfaces reveal
responsive and switching behavior. This can also be shown for polyelectrolyte brushes which are
sensitive on pH. Mixed polyelectrolyte - non polyelectrolyte and mixed oppositely charged
polyelectrolyte brushes were synthesized by "grafting to" and "grafting from" approaches on
solid substrates (Si-wafers and polymer films). The mixed brushes exhibits responsive
properties via exposure to organic solvents and water of different pH resulting in switching of
the brush morphology, surface energetic state, wettability, and thickness. From AFM
investigations different nanostructures are distinguished.
1-25
Nanoprobing of Switchable Polymer Surfaces
VLADIMIR V. TSUKRUK, Department of Materials Science and Engineering, Iowa State
University, 3155 Gilman Hall, Ames, IA, vladimir@iastate.edu
An overview of recent author's results on atomic force microscopy (AFM) probing of
nanomechanical and tribological properties is presented and discussed for a wide range of
switchable surfaces. We focus on mono- and binary polymer brushes (grafted to, grafted from,
and Y-shaped) studied under various conditions (in air, in fluid, and at elevated temperatures),
patterned surface films, and photochromic monodendrons of different generations.
1-26
Synthesis of Segregated Binary Polymer Brushes
IGOR LUZINOV, Yong Liu, Viktor Klep, School of Materials Science & Engineering Clemson
University, 161 Sirrine Hall, Clemson, SC, luzinov@clemson.edu
Communication is focused on synthesis of binary polymer brushes with phase-segregated
morphology. Namely, polystyrene/polyethylene glycol methyl ether methacrylate (PEGMA)
brushes were fabricated by combination of “grafting to” and “grafting from” techniques of the
polymer anchoring. A ultrathin film consisting of carboxyl-terminated polystyrene (PS) and
poly (methyl methacrylate) (PMMA) blend was first deposited on a substrate modified with
poly(glycidyl methacrylate) and annealed at 120 oC. As a result of the grafting islands of PS
brushes were created. To complete formation of the segregated binary brushes, surface initiated
polymerization (ATRP) of PEGMA was carried out. Surface rearrangements of the segregated
brushes were studied by contacting them with selective solvents.
1-27
Synthesis of Mixed Homopolymer Brushes on Silica Nanoparticles by Living Radical
Polymerization Techniques
Dejin Li, Xia Sheng, BIN ZHAO, Department of Chemistry, University of Tennessee, Knoxville,
TN, zhao@novell.chem.utk.edu
By using two different living radical polymerization techniques, atom transfer radical
polymerization (ATRP) and nitroxide-mediated radical polymerization (NMRP), we successfully
synthesized mixed poly(t-butyl acrylate) (PtBA)/polystyrene (PS) brushes on silica
nanoparticles. Silica particles were prepared by the Stöber process and were functionalized with
an asymmetric difunctional initiator-terminated monolayer. Surface-initiated ATRP of t-butyl
acrylate was carried out in the presence of a free initiator. Kinetics study showed that the
polymerization was well controlled. By cleaving PtBA off the particles, the molecular weights of
the grafted and free polymers were found to be essentially identical. Mixed PtBA/PS brushes
were obtained by NMRP of styrene from PtBA particles. The Mn of the grafted PS was found to
be the same as that of the free PS formed from the free initiator. Amphiphilic mixed poly(acrylic
acid) (PAA)/PS brush-coated nanoparticles were synthesized from mixed PtBA/PS particles by
hydrolysis of PtBA with iodotrimethylsilane. Tyndall scattering experiments and 1H NMR study
showed that the mixed PAA/PS particles can be dispersed and form a stable suspension in
CHCl3, a selective solvent for PS, and also in CH3OH, a selective solvent for PAA,
demonstrating the capability of these hairy nanoparticles to undergo chain reorganization in
response to environmental changes.
1-28
Novel Smart Core-Shell Microgels: Synthesis and Characterization
Man Fai Leung1, Junmin Zhu1, Frank W. Harris2, PEI LI1, 1Department of Applied Biology and
Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong
Kong, P. R. China, 2Maurice Morton Institute of Polymer Science, The University of Akron, OH,
bcpeili@polyu.edu.hk
Colloidal microgels that are able to alter their volume and properties in response to
environmental stimuli, such as pH, temperature and ionic strength are attractive candidates for
many potential applications. Recently, microgels with more complex structures, such as a multiresponsive core-shell, have received increasing attention due to the tuneable properties of the
individual responsive components. In this presentation, a new method to prepare smart microgels
that consist of well-defined temperature-sensitive cores with pH-sensitive shells will be
described. The microgels were obtained directly from an aqueous graft copolymerization of Nisopropylacrylamide and N, N-methylenebisacrylamide from water-soluble polymers containing
amino groups such as poly(ethyleneimine) and chitosan. The microgel diameters ranged from
300 to 400 nm with narrow size distribution. The unique core-shell nanostructures exhibited
tuneable responses to pH and temperature.
1-29
Collapse of Polyelectrolyte Brushes Driven by Ion Pairing Interactions
OMAR AZZARONI1, Sergio Moya2, Andrew A. Brown1, Tamer Farhan1, Wilhelm T. S.
Huck1,2, 1Melville Laboratory for Polymer Synthesis, Department of Chemistry, 2The
Nanoscience Centre, University of Cambridge, CB2 1EW, United Kingdom, oa219@cam.ac.uk
Polyelectrolyte brushes are ideal building blocks for soft nanotechnology and the engineering of
responsive surfaces. Changes in ionic strength, pH and solvent properties lead to markedly
difference on surface properties due to transitions in the polymer brushes between stretched and
collapsed states. The traditional framework in polyelectrolyte brushes describes collapse as the
result of a significant screening of the charges of the pendants groups. However, a much richer
behaviour should be expected when the specific chemical interactions between anions and
cations are explicitly studied. The introduction of chemical triggers of collapse (rather than
merely relying on ionic strength) will allow the development of surfaces which show responsive
behaviour that can be exploited as sensors, as well as actuating mechanisms in fluidic devices. In
this work we have investigated the critical role of ion–pairing interactions on the collapse of
cationic 2–(methacryloyloxy)ethyl–trimethylammonium chloride (METAC) polyelectrolyte
brushes. We observed that in the presence of ion–pairing interactions, the chemical nature of the
electrically neutral polymer can be sharply switched from hydrophilic to hydrophobic. This
chemical change of the monomer units leads to a collapse driven by hydrophobic interactions
with the surrounding water. As a consequence, ion–paired collapsed polyelectrolyte brushes
show very compact stiff structures markedly different from similar brushes whose collapse are
driven by Coulombic screening.
1-30
Thermally Responsive Polymer Brushes with High Protein-Binding Affinity
Andy Kusumo1, Lindsay Bombalski2, Qiao Lin3, Krzysztof Matyjaszewski2, Tomek
Kowalewski2, James W. Schneider1, ROBERT D. TILTON1,4, Departments of 1Chemical
Engineering, 2Chemistry, 3Mechanical Engineering, and 4Biomedical Engineering, 1Center for
Complex
Fluids
Engineering,
Carnegie
Mellon
University,
Pittsburgh,
PA,
tilton+@andrew.cmu.edu
Polymer brushes with tunable protein affinities can be useful for protein chromatography or
adsorptive pre-fractionation of crude cell lysate samples. Well controlled brushes of
poly(dimethylaminoethylmethacrylate) (PDMAEMA) are grown from thiol-linked initiators on
gold surfaces using atom transfer radical polymerization (ATRP). The lower critical solution
temperature (LCST) of the brushes is controlled by statistical copolymerization with
methylmethacrylate (MMA). The polymer grafting density is controlled by varying the relative
amounts of initiator and inert thiol in solution during the initial gold surface modification and is
quantified by surface plasmon resonance (SPR). At lower grafting densities, SPR measurements
indicate that these brushes have an unexpectedly high affinity for proteins, adsorbing the
equivalent of 10-15 monolayers of serum albumin within the brush, under good solvent
conditions. Above the LCST, the extent of adsorption increases slightly, but the adsorption rate
increases approximately ten-fold. In spite of the greater hydrophobicity of PDMAEMA-coPMMA compared to PDMAEMA, the protein adsorption is approximately 40-fold slower for the
copolymer brushes. This effect is tentatively attributed to a reduction in protein accessible
volume within the copolymer brush. The effects of temperature, protein hydrophobicity, brush
composition and grafting density on protein binding capacity will be discussed.
1-31
Strong Polyelectrolyte Brush at the Air/Water Interface
PLOYSAI KAEWSAIHA, Kozo Matsumoto, Hideki Matsuoka, Department of Polymer
Chemistry, Kyoto University, Katsura, Nishikyo, Kyoto, Japan, ploysai@star.polym.kyotou.ac.jp
We synthesized an ionic amphiphilic diblock copolymer having strong acid group;
poly(hydroganated isoprene)-b-poly(styrenesulfonic acid) (PIp-h2-b-PSS) by living anionic
polymerization, and the nanostructure of its spread monolayer on the water surface was directly
investigated by in situ X-ray reflectivity (XR) technique. The monolayer of a diblock copolymer
on a water surface had a smooth hydrophobic PIp-h2 layer on water and hydrophilic layer
consists of a dense ‘carpet layer’ just beneath the hydrophobic layer and ‘brush-like layer’
stretching into water. The surface pressure and PSS chain length dependence of its hydrophobic
layer thickness and the brush nanostructure were quantitatively studied. Furthermore, the effect
of salt concentration in the subphase was also investigated. The thickness of the PSS brush layer
decreased at salt concentrations above 0.2M while no nanostructure change was detected below
0.2M. This critical salt concentration corresponds to be that of free counterions inside the brush
layer. However almost all of counterions in the carpet layer might be condensed so that the
carpet layer structure is hardly changed by compression, or salt addition.
1-32
Stimuli-Responsive Polymer Based Composite Microcapsules
C. Déjugnat, T. Mauser, D. Haložan, K. Köhler, D. G. Shchukin, A. Skirtach, G. B.
SUKHORUKOV, Max Planck Institute of Colloids and Interfaces, Potsdam/Golm, Germany and
IRC at Biomedical Materials, Queen Mary University of London, London, UK, gleb@mpikggolm.mpg.de
Polyelectrolyte capsules representing a novel type of nano-engineered multifunctional materials
are made by layer-by-layer adsorption of oppositely charged polyelectrolytes on the surface of
colloidal template particles of 0.05-20 m diameter. A great variety of materials including
synthetic and natural polyelectrolytes, proteins, multivalent ions, organic nanoparticles, lipids
were used to build walls of hollow capsules. Many of them were functionalized to provide
special surface properties of technical or biological relevance. The possibility of tailoring
different functionalities, impregnating inorganic and organic substances both inside capsule
volume and in polyelectrolyte shell, controlled release of encapsulated material provided
continuous scientific and industrial interest for employing capsules as microcontainers and
microreactors. Inorganic nanoparticles incorporated to polyelectrolyte shell makes possible the
remote activated release. Smart polymers involved in capsule build-up exhibit reversible
sensitivity to environmental conditions, i.e. capable of undergoing sharp physical or chemical
modifications in response to external stimuli such as temperature, pH, ions, etc. Here we present
the results obtained with hollow and filled capsules prepared with stimuli-responsive polymers
and capsules filled with different polymers responsive to ions, pH and temperature. The
possibilities for practical applications of such capsules are illustrated.
1-33
Connecting the Wetting and Rheological Behaviors of PDMS-Grafted Nanospheres in
PDMS Melts
DAVID GREEN1, Jan Mewis2, 1Department of Chemical Engineering, University of Virginia,
102 Engineers’ Way, Charlottesville, VA, 2Department of Chemical Engineering, Katholieke
Universiteit Leuven, 46 Willem de Croylaan, 3001 Heverlee, Belgium, dlgreen@virginia.edu
Engineered nanocomposites are often formulated by grafting polymer brushes to the surfaces of
colloids to optimally disperse them into viscous polymer matrices. In spite of the ubiquity of
these filled materials, the essential mechanisms in producing an optimal dispersion have not been
well quantified. To this end, rheological and light scattering measurements are made to connect
the static wetting and dynamic flow properties of polydimethylsiloxane (PDMS)-grafted silica
nanospheres in PDMS melts. By controlling the brush grafting density and the matrix chain
length of these model systems, results indicate that the wetting and the flow behaviors can be
quantifiably linked. Overall, these studies represent new ways of quantifying the factors that
control the dispersion of polymer-grafted nanoparticles in viscous melts.
1-34
Counterion Condensation and Complex Formation on Polyelectrolytes
ULRICH SCHELER, Leibniz Institute of Polymer Research, Hohe Strasse 6, 01069 Dresden,
Germany, scheler@ipfdd.de
The effective charge of polyelectrolytes in solution is significantly lower than the nominal
charge, since a considerable fraction of the conterions is not free to move away from the
polymer, they are condensed on the polymer. Electrophoresis NMR combined with diffusion
NMR permits the direct determination of the charge of molecules and complexes. The effective
charge of poly(styrene sulfonate) is decreasing with increasing ionic strength of the solvent. For
low molecular weight the effective charge equals the nominal charge. With increasing molecular
weight the hydrodynamic friction increases, resulting a reduced diffusion coefficient, while the
electrophoretic mobility is constant after only an initial increase. From the combination of both
effects an increasing fraction of condensed counterions is concluded. Amino acids can bind to
macromolecules through electrostatic interaction. Glutamic acid in solution exhibits a negative
electrophoretic mobility, that is increasing by value with pH. The lower magnitude of the
electrophoretic mobility in the solution containing the polycation is due to exchange between
bound and free acid on the time scale of the experiment. At high pH the acid is fully dissociated
and strongly binds to PDADMAC resulting in an electrophoretic mobility close to that of the
polycation.
1-35
Polymer-Capped Monodisperse Magnetic Nanoparticles
M. LATTUADA, T. A. Hatton, Department of Chemical Engineering, Massachusetts Institute of
Technology, 77 Massachusetts Avenue, Cambridge MA, lattuada@mit.edu
We have prepared monodisperse magnetic nanoparticles following the organic route proposed by
Sun et al. [JACS, 2004, 126, 273]. The particles are stabilized by oleic moieties, and in order to
undergo further functionalization a surface ligand exchange reaction is performed by means of
which the oleic moieties are replaced by ricinoleic moieties. The additional hydroxyl group of
ricinoleic acid enables further reactions to take place. In particular the reaction with acid halides
bearing halogen atoms allows one turn the nanoparticles into macroinitiators for Atom Transfer
Radical Polymerization (ATRP). ATRP allows one to polymerize a large variety of monomers in
controlled conditions, which can impart to the so obtained polymer-capped nanoparticles a wide
range of properties. For example, by polymerizing PH or temperature sensitive monomers, one
can obtain water soluble monodisperse magnetic nanoparticles showing PH or temperature
induced reversible self-assembly. We have grown poly(meth)acrylic acid brushes from the
nanoparticle surface through polymerization of trimethylsilyl (meth)acrylate, followed by
hydrolysis to yield the PH responsive poly(meth)acrylic acid. The nanoparticles properties can
be further tailored by making use of amidation chemistry to attach a variety of molecules and
biomolecules to the carboxyl groups.
1-36
Improving Fuel Cell Performance by Controlling Polymer Membrane Architecture;
Nanoparticles for Enhanced Proton Conduction
THEO B. J. BLIJDENSTEIN, Norman J. Wagner, Center for Molecular and Engineering
Thermodynamics, Department of Chemical Engineering, University of Delaware, Newark, DE,
wagner@che.udel.edu
A key limiting factor for the performance of proton-exchange membrane fuel cells (PEMFC) is
the reduction in proton conductance, and hence, power output at “high” temperatures (100-150
C). For standard Nafion™ based systems, this is primarily due to the loss of water. Hydration of
the membrane is necessary for the percolation of self-assembled proton conduction channels in
the ionomeric membrane. It has been hypothesized that incorporation of nanoparticles has
proved to be beneficial for proton conduction at high temperatures/low humidity. In the work
presented, select NafionTM composite membranes were prepared by recasting from dispersions in
which particles with known size and surface charge were incorporated. We investigated how
colloidal NafionTM/silica-interactions in solution determine the structure of both the dispersions
and the resulting membranes. Techniques include rheology, light- and X-ray scattering, light
microscopy and scanning electron microscopy, altogether covering a wide range of length scales.
The performance of the composite membrane regarding proton conductivity and half-cell activity
will be presented and discussed in terms of the membrane microstructure and the water holding
capacity of the membranes.
1-37
Vapor Sensors Based on Gold Nanoparticle Interlinked with p-Oligophenyldithiols
Y. JOSEPH, B. Guse, A. Yasuda, T. Vossmeyer, Materials Science Laboratory, Sony
Deutschland GmbH, Hedelfinger Str. 61, D-70327 Stuttgart, Germany, joseph@sony.de
Recent efforts to control the physical and chemical properties of nanostructured materials
through a molecular level design have generated enormous interest in thin films comprised of
organically crosslinked metal nanoparticles. Here, we investigate films prepared by layer-bylayer self-assembly using solutions of dodecylamine-stabilised 4 nm Au-nanoparticles and
oligophenyldithiols of different lengths. The resulting films are 7 to 30 nm thick, as determined
by AFM and the dodecylamine ligands are exchanged by the crosslinking dithiols during film
assembly as revealed by XPS. Additionally, two main sulfur signals (S-Au, S-H) are observed
indicating that - interaction may be important for assembly. All films show linear currentvoltage characteristics and conductivities independent from the length of the linking molecule.
Conductivity measurements at variable temperature are consistent with an Arrhenius-type
activation of charge transport. For investigating the vapor sensing properties, coated
chemiresistors and quarz micro balances are dosed with vapours of toluene, 1-propanol, 4methyl-2-pentanone and water. Their resistances increase only slightly whereas the mass uptake
is significant in case of hydrophobic vapors. All results are compared with results from films
interlinked with alkanedithiols of similar lengths (C6, C9, C12).
1-38
Magnetic-field-guided Growth of Ferromagnetic Core-Shell Nanomaterials
Liyan Zhao, Karan Sukhija, Nina Heinig, Xiaojing Zhou, TONG LEUNG, WATLabs and
Department of Chemistry, University of Waterloo, Waterloo, ON, Canada, tong@uwaterloo.ca
Our recent work on metal nanoparticles (Cu, Ni, Co) electrochemically deposited on an ultrathin
polypyrrole film grown on a gold-coated silicon electrode shows that the morphology (size,
shape, density and distribution) of these nanostructured materials can be easily controlled by
varying the wet deposition conditions (pH, electrolyte concentration, deposition potential,
charge, and current density), and the thickness and morphology of the polypyrrole film. Using
similar electrochemical techniques, we have recently obtained mono-sized, uniformly distributed
Fe core-shell nanoparticles with two different morphologies: quantum dots of 4-10 nm in
diameter and 20110 nm “nano-surfboards” (<5 nm thick). These nanoparticles are found to
primarily consist of a Fe metallic core and a mixed Fe oxides shell (2-3 nm thick). In the present
work, we report the first evidence of morphological changes induced by an external magnetic
field during growth. Implications of constructing patterned nanostructured materials using this
technique will also be discussed.
1-39
Advanced Nanostructured Materials from Block Copolymer – Nanoparticle Assemblies
ULRICH WIESNER, Department for Material Science and Engineering, Cornell University, 329
Bard Hall, Ithaca, NY, ubw1@cornell.edu
The study of polymer based co-assembly (“bottom-up”) approaches to multifunctional polymerinorganic hybrid materials is an exciting emerging research area interfacing solid state and soft
materials and offering enormous scientific and technological promise. By choice of the
appropriate synthetic polymers as well as nanoparticle precursors unprecedented morphology
control down to the nanoscale is obtained. Tailoring of the polymer–inorganic interface is of key
importance. The structures generated on the nanoscale are a result of a fine balance of competing
interactions, a typical feature of complex biological systems. The potential for new
multifunctional materials lies in the versatility of the polymer chemistry as well as that of the
inorganic (nanoparticle) chemistry that can be exploited in the materials synthesis. In the present
contribution the synthesis and characterization of advanced nanostructured hybrid materials will
be presented with potential applications ranging from microelectronics to nanobiotechnology. In
all cases cooperative self-assembly of organic and inorganic species is induced by amphiphilic
macromolecules. Besides amorphous and crystalline oxide materials novel systems toward high
temperature SiCN and SiC structures are introduced. Examples will include the preparation of
mesoporous materials and superparamagnetic mesoporous materials with pore sizes ranging from
5-50 nm for separation technology and catalysis, solid hybrid polymer electrolytes for battery
applications, the synthesis of nanoparticles with controlled shape, size, and composition for
applications in the life sciences, as well as thin film materials with potential applications in
microelectronics and nanobiotechnology.
1-40
Electric Field Directed Assembly of Colloidal Particles into Nanostructured Thin Films and
Composites
J-C. Lin, D. Liu, M. Z. YATES, Department of Chemical Engineering and Laboratory for Laser
Energetics, University of Rochester, Rochester, NY, myates@che.rochester.edu
When an electric field is applied to a colloidal suspension, particles can exhibit a variety of
electrokinetic responses that may be exploited to manipulate particles and control their assembly.
For example, charged particles move to an oppositely charged electrode by electrophoresis,
particles migrate in an electric field gradient by dielectrophoresis, or field induced dipoles on
particles cause particles to aggregate in linear chains. Rod-shaped particles can be aligned by an
electric field with the longest axis parallel to the applied field. Here we report the fabrication of
thin films and composites containing aligned rod-shaped particles through a novel electric-field
driven process. The alignment direction of rod-shaped particles in the composite material is
controlled by the electrode geometry. Functional particles are selected that give the composite
material anisotropic optical and transport properties that are dependent on the alignment
direction. The films may find application in membranes and optical materials. The electric
field-driven process is applicable to the directed assembly of a variety of types of rod or plate
shaped particles to create advanced materials with controlled nanostructure.
1-41
Inversion of Emulsions Stabilised Solely by Ionisable Nanoparticles
B. P. BINKS, J. A. Rodrigues, Surfactant & Colloid Group, Department of Chemistry,
University of Hull, Hull,United Kingdom, b.p.binks@hull.ac.uk
Certain solid nanoparticles act as excellent emulsifiers of oil and water in the absence of any
surface-active agent and, since particles are strongly attached to interfaces, coalescence tends to
be absent. However, different types of particles are needed to prepare either oil-in-water (o/w) or
water-in-oil (w/o) emulsions in mixtures containing equal volumes of the two liquids. Here we
describe a new class of solid particle emulsifier capable of stabilising both emulsion types
efficiently. The spherical nanoparticles are those of polystyrene whose surfaces contain ionisable
carboxylic acid groups. Inversion of the emulsion type is simply effected by either an increase in
pH or salt concentration, both driving the inversion from w/o to o/w. The emulsions are studied
using conductivity, optical microscopy and stability measurements. The origin of inversion is
due to the change in the wettability of the particles at the interface, brought about by increasing
the degree of dissociation of acid groups, rendering particles more hydrophilic as a result.
1-42
A New AC Electrokinetic Technique for Collection and Manipulation of Particles on
Patterned Electrodes
KETAN H. BHATT1, Orlin D. Velev1, Sonia Grego2, 1Department of Chemical and
Biomolecular Engineering, North Carolina State University, Raleigh, NC, 2MCNC Research and
Development Institute, Research Triangle Park, NC, khbhatt@unity.ncsu.edu
We report a new type of microfluidic chip that collects and concentrates colloidal particles from
bulk liquid medium using AC electrokinetics. The alternating electric fields were applied to
dilute suspensions of latex microspheres enclosed between a patterned silicon wafer and an ITOcoated glass slide. The latex particles entrained by a liquid flow were collected in the center of
the conductive "corral" patterns. The particle collection efficiency and speed depended only on
the frequency and strength of the applied field and were independent of the material properties of
the particles or the electrodes. The leading effect in the particle collection process is AC
electrohydrodynamics (EHD). We discuss how the EHD flows emerge from the spatially nonuniform field and interpret the experimental results by means of electrostatic and hydrodynamic
simulations. We demonstrate on-chip collection of latex particles, yeast cells and microbes. The
technique allows three-dimensional microfluidic pumping and transport by use of twodimensional patterns.
1-43
Temperature-Induced Phase Inversion of Emulsions Stabilized by Latex Particles Alone
B. P. Binks1, R. MURAKAMI1, S. P. Armes2, S. Fujii2, 1Surfactant & Colloid Group,
Department of Chemistry, University of Hull, Hull, United Kingdom, 2Department of Chemistry,
University of Sheffield, Sheffield, S3 7HF, United Kingdom, r.murakami@hull.ac.uk
Aqueous dispersions of poly[2-(dimethylamino)ethyl methacrylate-block-methyl methacrylate]
(PDMA-PMMA)-stabilized polystyrene latex particles (diameter = 150 nm) were synthesised
and used as sole emulsifiers of hexadecane and water (1:1) at various temperatures. At low
temperatures (≤ 50 °C) oil-in-water emulsions form which are stable to coalescence but exhibit
creaming. At high temperatures (≥ 65 °C) water-in-oil emulsions form which are unstable to
coalescence. At intermediate temperatures (55-65 °C), emulsions could be of either type. Thus
transitional inversion takes place in the same direction as that occurring in nonionic surfactantstabilised emulsions. Microscopy observations of the aqueous dispersions indicate flocculation
of the particles with increasing temperature. Furthermore, the contact angles of a water drop
under hexadecane on a glass substrate coated by PDMA homopolymer increase with increasing
temperature, implying an increase in system hydrophobicity. A mechanism to understand this
inversion involves consideration of changes in the hydration and ionization of the exterior amino
groups on particle surfaces with increasing temperature.
1-44
The Synthesis of FePt Nanoparticles by Two-Liquid Mixing Method
2-01
Nanosize Particles as Building Blocks for Uniform Colloids of Different Morphologies
EGON MATIJEVIĆ, Center for Advanced Materials Processing, Clarkson University, Potsdam,
NY, smetcalf@clarkson.edu
This talk will address the problems involved in the formation of uniform colloids of different
particle shapes. Specifically, the focus will be on the mechanisms by which such particles are
generated by aggregation of nanosized precursors. Both chemical and physical aspects of the
involved phenomena will be illustrated.
2-02
Applications of Light Scattering Techniques for Determining Doublet Formation Rate of
Colloidal Systems
M. Lattuada, Z. Jia, H. WU, A. Vaccaro, J. Sefcik, M. Morbidelli, Swiss Federal Institute of
Technology Zurich, ETHZ, Institut für Chemie-und Bioingenieurwissenschaften, ETHHönggerberg/HCI, CH-8093 Zürich, Switzerland, hua.wu@chem.ethz.ch
The formation rate of a doublet from two primary particles is one of the fundamental
characteristics of a colloidal system. It gives direct estimate of the Fuchs stability ratio W, which
can be used to estimate the effective surface charge and is also a prerequisite in the simulations
of aggregation kinetics using the population balance equations. Among the available techniques
in the literature, those based on light scatterings are most commonly used, because they are
noninvasive and supported by sound scattering theories. However, those relying on the dynamic
light scattering have ignored the effect of the rotational motion on the measured hydrodynamic
radius of the doublets. In the present work, we analyze and show that this effect is significant for
a doublet, in the cases of qRp>1 (q is the scattering wavevector and Rp is the radius of primary
particles). Thus, before such an effect can be quantified, care must be taken in the applications of
the dynamic light scattering to determine the doublet formation rate. Therefore, we have
proposed a technique that is based only on the static light scattering (SLS) experiments to
determine the doublet formation rate. In particular, this technique monitors the very initial stage
of the aggregation, where the system is dominated by only primary particles and doublets. It first
determines the conversions of the primary particles to doublets x at different aggregation times
by reconstructing the average structure factors of the aggregating system obtained from the SLS
experiments. Then, considering the second-order kinetics of the doublet formation, we can obtain
the doublet formation rate from the time-dependence of the conversion x, which in turn gives the
estimate of the Fuchs stability ratio W. Several aggregation experiments have been carried out to
demonstrate the applicability of the proposed technique.
2-03
Destabilization of silica nanoparticles suspensions with Al13 polycations
C. PARNEIX1, B. Cabane2, J. Persello1, 1Laboratoire de Chimie des Matériaux et Interfaces,
Université de Franche-Comté –16 route de Gray, 25030 Besançon Cedex, France, 2Laboratoire
PMMH, ESPCI - 10 rue Vauquelin, 75231 Paris Cedex 05, France, caroline.parneix@univfcomte.fr
Although Al13 polycations (Al12VI(OH)24AlIVO4(H2O)127+) are widely used as coagulants in the
water treatment industry, the mechanisms by which they interact with colloidal particles
suspended in water and induce their aggregation are not fully understood. We study here how
silica sols with different particle sizes in the range 10-25 nm and with pH adjusted to 5 or 9 are
destabilized with addition of Al13 polycations. After turbidimetric determination of the
aggregation kinetics, the interactions between silica and Al13 as well as those between
nanoparticles in presence of Al13 are characterized. The aluminum species present both at the
surface of particles and in the dispersion medium are identified using 27Al NMR spectroscopy,
whereas osmotic pressure measurements allow us to investigate the modification of interactions
between particles with the rate of added coagulant and pH of the dispersion. Small angle neutron
scattering experiments provide us additional information about interactions between particles but
also about the structure of the aggregates formed. Beside the differences revealed in the
aggregation kinetics and the amount of Al13 required for aggregation at pH 5 and 9, suggesting
different destabilization mechanisms, the variation of the aggregation conditions appears as a
mean to control the morphology of the silica aggregates.
2-04
Heteroflocculation induced by montmorillonite plates acting as bridging agents
Alois Vanerek, Bob Alince, THEO G. M. VAN DE VEN, Pulp and Paper Research Centre and
Department of Chemistry, McGill University, 3420 University Street, Montreal, QC, Canada,
theo.vandeven@mcgill.ca
In papermaking, a microparticulate retention aid system consisting of bentonite and high
molecular weight cationic polymer is commonly used to incorporate mineral pigments in the
fiber web. It is believed that the mechanism by which bentonite operates is based on the ability
of montmorillonite (its main component) to form a bridge between polymer-covered fibers and
colloidal particles, resulting in heteroflocculation. Its performance appears to be related to its
ability to delaminate montmorillonite. A common way to promote montmorillonite delamination
is treating it with sodium-rich solutions. A novel way of enhancing montmorillonite
delamination is to break-up aggregates of fibers held together by montmorillonite stacks. The
extent of montmorillonite delamination was evaluated by measuring the deposition of calcium
carbonate pigments on fibers coated with cationic polyacrylamide suspended in water. The
results show that the flocculation efficiency of montmorillonite strongly depends on its ability to
delaminate. Montmorillonite is most effective when it is completely delaminated, in which case
single plates form strong bridges between polymer-coated particles.
2-04
Controlling porosity within colloidal heteroaggregates
D. R. E. SNOSWELL, T. Rogers, B. Vincent, School of Chemistry, Bristol University, Bristol,
United Kingdom, David.Snoswell@Bristol.ac.uk
Heteroaggregates of cationic poly(2-vinylpyridine) microgels, anionic polystyrene latex and
anionic silica particles have been made by mixing dilute, aqueous suspensions. The resulting
heteroaggregate flocs were then concentrated by vacuum filtration, freeze dried, and
characterized by mercury porosimetry, SEM and TEM imaging techniques. Control of the pore
volumes within the dried filter cakes is demonstrated by two techniques. In the first technique,
heteroaggregation at a constant KCl concentration was stopped or ‘arrested’ by the subsequent
addition of silica particles, thereby limiting the size of the flocs. Pore volume was shown to
increase as the aggregation time prior to ‘arrest’ was increased. In the second technique, the
aggregation time prior to arrest was maintained constant while the KCl concentration was varied.
The pore volume of the aggregates decreased as the electrolyte concentration increased. The
method of arresting the heteroaggregation potentially allows high volume fractions of flocs to be
made without the formation of a gel which is difficult to process, thereby providing a method of
manufacturing materials with controllable porosity. In addition, incorporation of swellable
microgels in a porous structure offers potential for creating novel structures suitable for
controlled release applications.
2-06
Aggregation Kinetics of Alginate-Coated Hematite Colloids in Divalent Electrolytes
KAI LOON CHEN1, Steven E. Mylon2, Menachem Elimelech1, 1Department of Chemical
Engineering, Environmental Engineering Program, Yale University, New Haven, CT,
2
Department of Chemistry, Lafayette College, Easton, PA, kailoon.chen@yale.edu
Aggregation kinetics of alginate-coated hematite colloids is measured in the presence of divalent
electrolytes (CaCl2 and MgCl2) by dynamic light scattering. It is shown that alginate undergoes
inter-polymer binding in presence of calcium ions, but not with magnesium ions. The
aggregation kinetics of the alginate-coated hematite colloids in the presence of the divalent
cations is compared with the kinetics in monovalent electrolyte (NaCl). We find that the
alginate-coated hematite colloids undergo aggregation by electrostatic destabilization with
sodium or magnesium ions, while the aggregate growth rate is much higher with calcium ions.
In the case of aggregation with calcium ions, transmission electron microscopy (TEM) reveals
hematite colloids enmeshed within clusters of alginate network. We propose that the enhanced
aggregation with calcium ions is due to the formation of extended alginate cross-links around the
alginate-coated colloids, which greatly increases their collision radii. It is also found that the
presence of sodium as a background electrolyte is detrimental to this calcium-induced enhanced
aggregation.
2-07
Light driven aggregation of core-shell chromophoric colloids
MARTIN PIECH, Nelson S. Bell, Sandia National Laboratories, Chemical Synthesis and
Nanomaterials Department, NM, mpiech@sandia.gov
A photo-controlled aggregation in non-polar solvents has been achieved using spirobenzopyran
methylmethacrylate (SP-MMA) polymer layers grafted from silica particles. The chromophoric
molecules incorporated into these core-shell architectures can be switched from a non-polar
closed form (spirobezopyran) to the open, zwitterionic form (merocyanine) through exposure to
ultraviolet (UV) irradiation (~360 nm). Subsequent visible light irradiation (540 nm) or
heat treatment reverses this process. Here, this molecular isomerization reaction was employed
to drive colloidal aggregation in border-line solvents. The process is reversible, with the
requirement of agitation to redisperse the particles following agglomeration. System fatigue is
minimal yielding reproducible results even after a large number of cycles. Dependence of
sedimentation behavior on solvent polarity and chromophore content within the SP-MMA layers,
system rheological response, and particle adsorption behavior onto optically patterned surfaces
are discussed.
2-08
Crystalloluminescence in the Synthesis of Nanosized Particles
Terry A. RING, Department of Chemical Engineering, University of Utah, Salt Lake City, UT,
T.Ring@m.cc.utah.edu
A new nucleation theory will be presented which allows the prediction of the particle size
distribution of atomic clusters. This theory accounts for the collisions of atoms with clusters and
clusters with other clusters according to the free energy driving force for their collision and the
frequency of their collision by various mixing methods. The frequency of their collision can be
predicted by either diffusion or shear induced or turbulence induced models. The free energy for
these collisions is a function of the bonding geometry of the initial cluster(s) and resulting
cluster. This free energy information is available in a limited number of alkali metal systems
from quantum mechanics. The resulting partial differential integral equations are solved for
limiting cases, which are used to predict the cluster size distribution. Another benefit of this
theory of nucleation is an explanation of crystalloluminescence - light produced during
nucleation, which can be used to control the nanosynthesis process so that a very narrow range of
clusters is produced.
2-09
Fabrication of novel types of colloidosomes and liposomes with gelled cores
Paul Noble1, Olivier Cayre1, Rossitza Alargova2, Orlin Velev2, VESSELIN N. PAUNOV1,
1
Surfactant & Colloid Group, Department of Chemistry, University of Hull, Hull, United
Kingdom, 2Department of Chemical Engineering, North Carolina State University, Raleigh, NC,
V.N.Paunov@hull.ac.uk
Colloidosomes and liposomes are core-shell structures that consist of an aqueous core and a shell
formed by fused colloidal particles or lipid bilayers. Recently, it has been recognised that such
microcapsules offer a great potential in controlling the permeability of entrapped species in
pharmaceutical, cosmetic and food products.
Here we report a versatile fabrication method of novel colloidosomes microcapsules which is
based on the following 3 stages: (i) Hot aqueous solution of gelling hydrocolloid is emulsified in
a suitable oil in the presence of solid polymer particles dispersed in the aqueous phase to produce
a water-in-oil emulsion stabilised by the solid particles and the system is cooled off to set the gel.
(ii) The produced suspension of aqueous gel microcapsules coated with a particle monolayer is
separated by filtration to remove the oil phase. (iii) The microcapsules are washed and collected
into water. This methodology allows us to produce colloidosome microcapsules of diameters
varying between several tens of micrometers to several hundreds of micrometers. The function of
the gel cores was to support the particle shell around them and to give the microcapsules enough
stiffness to be separated from the oil phase by filtration.
Following this technique we have been able produce three different types of colloidosome
microcapsules. (a) By combining monodisperse amino-latex microparticles and an oil which
swells the latex we have fabricated integral colloidosomes of porous membrane where the pore
size is controlled by the degree of swelling. (b) By using monodisperse amino-latex particles and
cross-linking agent we were successful in producing colloidosomes of spherical particle
monolayers, where the membrane pores are defined by the particle size. (c) By using polymer
micro-rod particles as emulsifiers we have synthesized for the first time “hairy” colloidosomes
which shells consists of randomly assembled rod-like particles.
We also report the fabrication of novel hybrid giant liposomes with cores of an aqueous gel
based on an extension of the Pautot technique. It involves the following three steps: (i) A lipidstabilised water-in-oil emulsion is prepared in the presence of a gelling hydrocolloid in the
aqueous phase. (ii) The water drops, coated with a lipid monolayer are gelled at lower
temperature to produce gel beads. (iii) The gelled beads are transferred from the oil phase
through the planar oil-water interface where they pick up a second lipid monolayer and convert
into giant liposomes of gelled aqueous cores. We maintain a saturated lipid monolayer at the
planar oil-water interface by injecting lipid solution in a spreading solvent. These novel
microcapsules have higher stability and mechanical strength than conventional liposomes and
may find applications as drug delivery vehicles and for controlled release of proteins, vacines,
cosmetic and food supplements.
2-10
Aggregation, cluster formation and gelation in colloidal suspensions: From photonic liquids
to equilibrium clusters and gels
PETER SCHURTENBERGER, Department of Physics, University of Fribourg, CH-1700
Fribourg, Switzerland, peter.schurtenberger@unifr.ch
With the equilibrium behavior of colloidal systems seemingly well-understood, attention recently
turned to non-equilibrium phenomena. In particular the influence of attractive interactions of
variable strength and range has been investigated intensively, and it has been demonstrated that
the presence of a short ranged attraction can lead to fascinating phenomena that include
metastable liquid-liquid phase separation and dynamically arrested states such as attractive and
repulsive glasses as well as transient gels. These issues of interparticle interaction, aggregation,
cluster and crystal formation and dynamical arrest are of central importance to a variety of topics
ranging from cluster formation in various diseases to the production of photonic crystals.
In my lecture I shall outline the various aggregation phenomena that can be observed upon
combining short or long range attraction with either a hard and/or soft repulsion. I shall in
particular aim at demonstrating the generality of the emerging description on the phase
behaviour of a wide range of colloidal suspensions.
2-11
Direct Imaging of Phase Behavior and Structure of a Strongly Adsorbing MicrosphereNanoparticle System
JAMES F. GILCHRIST1, Angel T. Chan2, Eric R. Weeks3, Jennifer A. Lewis2, 1Department of
Chemical Engineering, Lehigh University, 111 Research Dr., Bethlehem, PA, 2Department of
Materials Science and Engineering, University of Illinois, 105 South Goodwin, Urbana, IL,
3
Department of Physics, Mail stop 1131/002/1AB, 400 Dowman Dr., Emory University, Atlanta
GA, gilchrist@lehigh.edu
We have investigated the phase behavior and 3D structure of a model microsphere-nanoparticle
system possessing high charge and size asymmetry in which polystyrene nanoparticles (D = 21
nm) strongly adsorb to silica microspheres (D = 1.18 mm).
By varying the
nanoparticle:microsphere ratio, we can tailor the transitions between stable fluid and attractive
gel phases. Using confocal fluorescence scanning microscopy, we directly observe their 3D
structure of as a function of varying composition. In the absence of nanoparticle additions, the
electrostatically charged microspheres reside in a stable fluid phase that crystallizes upon
sedimentation. As the nanoparticle concentration is initially increased, strong gelation occurs via
nanoparticle bridging between colloidal microspheres. At higher nanoparticle concentrations,
nanoparticle-coated microspheres are again stabilized by electrostatic interactions. We
demonstrate how this fluid-gel-fluid transition can be utilized to control the morphology of both
colloidal crystals and gels formed under gravity-driven sedimentation.
2-12
Direct visualization of the coupled aggregation and sedimentation of weakly interacting
colloid-polymer mixtures
MYUNG HAN LEE, Eric M. Furst, Department of Chemical Engineering, University of
Delaware, 150 Academy St., Colburn Lab., Newark, DE, lee@che.udel.edu, furst@che.udel.edu
Particle aggregation is of great interest not only due to its occurrence in biological systems,
paints and coatings, and numerous foods, but also due to its fundamental role as a simple model
system for growth under non-equilibrium conditions. In the past decade, most work has focused
on the cluster geometry and growth kinetics in the absence of sedimentation. However, many
real aggregation phenomena are influenced by sedimentation. The knowledge of colloidal
aggregation in a gravitational field will help to create a thorough understanding of processes
occurring in real aggregating systems. Through the use of confocal microscopy, we investigate
the coupled aggregation and sedimentation of colloidal particles in polymer solutions as a
function of the strength of attraction between particles. We discover that strong coupling
between aggregation and sedimentation occurs which limits the growth of clusters depending on
the magnitude of attractive forces, resulting in structures of various degrees of compaction.
Lastly, we examine the aging of the sediments. Internal restructuring due to gravitational stresses
drives the compaction and rearrangement of the gel with time. At high polymer concentration,
the particle-particle bonds are not easily broken and the flocs cannot freely reorganize to form
compact structures due to the high magnitude of the interaction at contact.
2-13
Aggregation Time Required for the Bottom-Up Assembly of Colloids
ALLISON M. YAKE, Darrell Velegol, Department of Chemical Engineering, The Pennsylvania
State University, University Park, PA, amy151@psu.edu
Numerous studies have demonstrated the bottom-up assembly of complex structures such as
colloidal crystals, close-packed aggregates, and even rings and tetramers. We show the
production of a simple localized and nanoscale charge distribution on the surfaces of individual
colloidal microspheres using our technique of “particle lithography”. In this technique, parts of
the microspheres are masked off, while polyelectrolytes cover the remaining portions of the
microspheres. The effectiveness of this process is demonstrated by the accurate and reproducible
production of colloidal heterodoublets composed of oppositely-charged microspheres. The
particle lithography technique is advantageous since it is not limited by the resolution of
photolithography or by functionalizing chemistries. A key challenge for the processing of
heterodoublets and more complex aggregates is knowing the time required for the assembly to
occur. A model has been developed that relates the aggregation times of the colloidal
microspheres to their size and concentration in the assembly suspension. This model investigates
the Brownian rotation of the microspheres and gives predictions about the experimental times
required for the particle lithography technique. Results are presented for the formation of
heterodoublets and the aggregations times of microspheres with varying particle suspension
conditions.
2-14
Film Formation and Gelation Process Studied by Multispeckle DWS
A. BRUN1, L. Brunel1, P. Snabre2, 1Formulaction, 10 Impasse Borde Basse, 31240 L’Union,
France, 2 Centre de Recherche Paul Pascal, Avenue Albert Schweitzer, 33600 Pessac, France,
brun@formulaction.com
We present in this work a new optical technique to study film or gel formation from colloidal
systems. Our technology is based on diffusing wave spectroscopy (DWS), an extension of
classical dynamic light scattering (DLS) to concentrated and opaque media. This new, noninvasive and very simple technique allows monitoring of the “media movement speed” from all
kind of dispersed systems such as latexes, emulsions, or solvent-born suspensions. Using a laser
source and a video camera as receptor, we have developed an original multi-speckle DWS
technique using a simple and direct processing of the light backscattered from the system. The
kinetics of bulk aggregation is displayed in real time by specific software.
Different film forming products have been investigated (e.g., water-based, solvent and solventfree paints, inks, adhesives, varnishes, coatings) on various types of substrates (e.g., metal,
plastic, glass, PMMA) and at different thickness from few microns to hundreds of microns.
Preliminary experiments on gelation of yoghurt and gelatine have also been performed. From the
kinetics, a wide range of information can be extracted such as objective gelation or drying times
(e.g., dust-free, touch-dry, dry-hard), mechanism taking place (e.g., solvent evaporation,
coalescence, cross-linking), thereby offering new possibilities to investigate these complex
colloidal systems.
2-15
Role of Electrostatic Interactions in Bacterial Deposition
MENACHEM ELIMELECH, Sharon L. Walker, Alexis J. de Kerchove, Department of
Chemical Engineering, Environmental Engineering Program, Yale University, New Haven, CT,
menachem.elimelech@yale.edu
The influence of bacterial electrokinetic properties and surface bound lipopolysaccharides (LPS)
on cell deposition (adhesion) are examined using three mutants of Escherichia coli K12 with
well-characterized LPS of different lengths and molecular composition. Two experimental
techniques, a packed bed column and a radial stagnation point flow system, are employed to
investigate bacterial adhesion kinetics onto quartz surfaces over a wide range of solution ionic
strengths. Although the two systems capture distinct deposition (adhesion) mechanisms because
of their different hydrodynamics, similar deposition kinetics trends are observed for each
bacterial strain. Bacterial deposition rates are directly related to the electrostatic double layer
interaction between the bacteria and quartz surfaces, in qualitative agreement with classic DLVO
theory. However, DLVO theory does not fully explain the deposition behavior for the bacterial
strain with the lengthy, uncharged O-antigen portion of the LPS. Neither the length nor the
charge characteristics of the LPS molecule directly correlated to deposition kinetics, suggesting a
complex combination of cell surface charge heterogeneity and LPS composition controls the
bacterial adhesive characteristics. It is further suggested that bacterial deposition behavior is
determined by the combined influence of DLVO interactions, LPS-associated chemical
interactions, and the hydrodynamics of the deposition system.
2-16
Study of Correlation of Adsorption and Interaction of Ceria Nanoparticles with Silica
Surface
IGOR SOKOLOV1, Quy K. Ong1, Nina Chechik2, David James2, 1Physics Department, Clarkson
University, Postdam, NY, 2Rohm and Haas Electronic Materials, Newark, DE,
isokolov@clarkson.edu
Using light scattering technique, we developed a new method for detection of the adsorption of
~50 nm ceria particles on silica wafers. Adsorption of the particles was studied in aqueous
solutions of different acidity, pH 4,5,6,7,8, and 9. It is of fundamental interest to compare these
data with the forces between individual particles and silica surfaces. We use the atomic force
microscopy (AFM) to measure such forces directly. We report a new method to modify the AFM
probe to get a single nanoparticle on the probe apex. Using this method, we are able to study the
interaction between individual ceria particles and silica surface, both long-range and contact
(adhesion) forces in aqueous solutions of the same acidity as above. The obtained data and
correlation between the measured adsorption and forces are discussed.
2-17
Marangoni effect reverses coffee-ring depositions
HUA HU1, Ronald G Larson2, 1Polymer Division National, Institute of Standards and
Technology, 100 Bureau Drive, Gaithersburg, MD, 2Department of Chemical Engineering,
University of Michigan, MI, huhuadce@engin.umich.edu
We report here that Marangoni effect reverses coffee-ring depositions. Most of particles deposit
at the center of the droplet, rather than the edge, due to a Marangoni flow induced during droplet
evaporation. We develop a full analytical solution to the temperature and velocity fields in the
drying droplet to analyze the particle deposition process. The measurement of the fluid flow in
the drying droplet confirms our theoretical analysis. Combining the analytical solution for the
flow field with Brownian dynamics simulations, we are able to compare our experimental results
for particle deposition with predictions. The good consistent between experiment and theory is
obtained.
2-18
Controlled Deposition and Modification of Conductive and Antireflective Nanoparticle
Coatings
Brian G. Prevo, Yeon Hwang, ORLIN D. VELEV, Department of Chemical and Biomolecular
Engineering, North Carolina State University, Raleigh, NC, odvelev@unity.ncsu.edu
The convective assembly method for particle deposition was originally designed for assembling
colloidal crystals from monodisperse particles for photonic applications. However, we will
demonstrate that the method allows facile controlled fabrication of nanoparticle coatings with a
range of other useful properties. Two types of nanocoatings that will be presented are conductive
metallic films from gold nanoparticles, and antireflective (AR) films from silica microspheres.
Uniform nanocoatings were deposited in minutes directly from aqueous suspensions by
convective assembly at high volume fraction. Operational ‘phase’ diagrams were constructed,
relating the crystal layer thickness and packing symmetry to the process parameters. The
deposition process allows control over the coating thickness, number of layers, optical
properties, and the electric conductance of the films (in the case of the gold nanocoatings). By
varying the deposition speed of the AR silica coatings, the band of optimal transmission could be
tuned across the breadth of the visible spectrum (from 450 to 650 nm). The AR coatings were
further optimized by the use of particle mixtures, which reduced the reflectance loss on glass by
up to 89%. The nanocoatings developed could be used in applications ranging from
nanoelectronics to energy efficient windows and solar cells.
2-19
Faradaic Reactions as the Source of Net Interparticle Motion Driven by ~100 Hz
Alternating Electric Fields
JEFFREY A. FAGAN, Dennis C. Prieve, Paul J. Sides, Department of Chemical Engineering,
Carnegie Mellon University, Pittsburgh, PA, jfagan@andrew.cmu.edu
Over the past decade, observations of net interparticle motion above a planar electrode due to
alternating electric fields have been explained by multiple different force mechanisms. While
past results indicate that multiple mechanisms are dominant over different frequency ranges, at
frequencies for which electrode reactions are important, new results suggest that these reactions
are the root cause of both net lateral and vertical particle motion. This talk details the connection
between the vertical forces induced by the application of an alternating field in the 30 Hz to 250
Hz frequency range, and new predictions of electrolyte dependent lateral motion that closely
match published experiments.
2-20
Galvanic Cell Mediated Colloidal Crystallization
PENG JIANG, Dudley A. Saville Ilhan A. Aksay, Department of Chemical Engineering,
Princeton University, Princeton, NJ, pjiang@Princeton.edu
We report a novel method for assembling micropatterned colloidal crystals using in-situ,
spontaneous, galvanic action whereby crystalline arrays can be created by a “galvanography”
technique. For example, by confining particles to shallow trenches, two-dimensional (2D)
ordered single crystals were formed. We observed a sort of repulsion of silica particles from
oppositely charged galvanic electrodes and crystallization on those with the same polarity. These
are counterintuitive based on electrostatic considerations and appear to result from a bulk
electroosmotic fluid flow (EOF) associated with galvanic process. To our knowledge, this is the
first report of electrokinetics in the context of the centuries-old galvanic cell concept. This
technique has applications in the construction of electrophoretic microchips for the separation of
particles with different surface charges. In addition to the activity of a bimetallic galvanic cell, a
single polycrystalline metal will also induce preferential colloidal crystallization via galvanic
processes.
2-21
In Situ Layer-by-Layer Film Formation Kinetics under an Applied Voltage Measured by
Optical Waveguide Lightmode Spectroscopy
A. PASCAL NGANKAM, Paul R. Van Tassel, Department of Chemical Engineering, Yale
University, New Haven, CT, andre.ngankam@yale.edu
Layer-by-Layer (LbL) thin film assembly occurs via the alternate adsorption of positively and
negatively charged macromolecular species. We investigate here the control of LbL film growth
through the electric potential of the underlying substrate. We employ optical waveguide
lightmode spectroscopy (OWLS) to obtain in situ kinetic measurements of poly(allylamine
hydrochloride)/poly(sodium 4- styrenesulfonate) (PAH/PSS) and poly(L-lysine)/dextran sulfate
(PLL/DXS) multilayer film formation in the presence of an applied voltage difference (DV)
between the adsorbing substrate, an indium tin oxide (ITO) coated waveguiding sensor chip, and
a parallel platinum counter electrode. We find initial layer adsorption to be significantly
enhanced by an applied potential for both polyelectrolyte systems: the mass and thickness of
(positively charged) PAH and PLL layers on ITO are about 60% and 500% larger, respectively,
at DV = 2 V than at open circuit potential (OCP), in apparent violation of electrostatics. A
kinetic analysis reveals the initial attachment rate constant to decrease with voltage, in agreement
with electrostatics. To reconcile these results, we propose a more coiled and loosely bound
adsorbed polymer conformation at higher applied potential. Following 10 adsorption steps, the
mass and thickness of a PAH/PSS film grown under DV = 2 V are about 15% less than those of
a comparable film grown under OCP, reflecting a lower degree of complexation between
adsorbing polyanions and more highly coiled adsorbed polycations. Following 14 adsorption
steps, the mass and thickness of a PLL/DXS film grown under DV = 2 V are about 70% greater
than those of a comparable film grown under OCP, reflecting the increased charge
overcompensation in the initial layer. We find the scaling of film mass (M) with the number of
adsorption steps (n) to be linear in the PAH/PSS system and exponential in the PLL/DXS
system, irrespective of applied voltage. The formation kinetics of PLL/DXS, but not PAH/PSS,
change qualitatively under voltage: PLL adsorption is slow to reach a plateau, possibly due to the
formation of secondary structure, and a decrease in film mass occurs toward the end of each
DXS adsorption step, suggesting a spontaneous removal of some PLL/DXS complexes from the
film.
2-22
Secondary Energy Minima and Surface Charge Heterogeneities Cause Breakdown of
Classical Filtration Theory
NATHALIE TUFENKJI, Department of Chemical Engineering, McGill University, Montreal,
QC, Canada, nathalie.tufenkji@mcgill.ca
The mechanisms and causes of deviation from the classical colloid filtration theory (CFT) in the
presence of repulsive DLVO interactions were investigated. The deposition behavior of uniform
polystyrene latex colloids in columns packed with spherical soda-lime glass beads was
systematically examined over a broad range of physicochemical conditions, whereby both the
fluid-phase effluent particle concentration and the profile of retained particles were measured.
Experiments conducted with three different-sized particles in a simple (1:1) electrolyte solution
reveal the controlling influence of secondary minimum deposition on the deviation from CFT.
To verify the validity of CFT in the absence of surface charge heterogeneities, two additional
sets of experiments were conducted using solutions of high pH or containing anionic surfactant
(sodium dodecyl sulfate). The results indicate that both secondary minimum deposition and
surface charge heterogeneities contribute significantly to the deviation from CFT generally
observed in colloid deposition studies.
2-23
Particle Deposition onto Micro-patterned Charge Heterogeneous Substrates
N. NAZEMIFARD1, S. Bhattacharjee1, J.H. Masliyah 2, 1Department of Mechanical
Engineering, University of Alberta, Edmonton, AB, Canada, 2Department of Chemical &
Materials
Engineering,
University
of
Alberta,
Edmonton,
AB,
Canada,
neda.nazemifard@ualberta.ca, Subir.B@ualberta.ca
The effect of collector surface charge heterogeneity on particle deposition efficiency is
theoretically investigated near a micro-patterned charged substrate under radial impinging jet
flow conditions. The surface charge heterogeneity on the collector is modeled as concentric
bands of positive and negative charges having specified width and pitch, providing alternating
favorable and unfavorable deposition sites for the particles. The fluid velocity distribution for
radial impinging jet flow is obtained numerically. Using this velocity distribution, particle
trajectories, concentration distributions, deposition fluxes, and collector efficiencies are obtained.
The periodic charge heterogeneity on the substrate engenders an oscillating particle trajectory
near the collector. Due to the coupled effects of hydrodynamic and colloidal forces, a region at
the leading edge of each favorable band on the collector becomes inaccessible for particle
deposition, implying that the actual favorable area fraction of the collector is less than its
nominal value. Utilizing the actual favorable area fraction of the collector, one can modify the
patchwise charge heterogeneity model to calculate the collector deposition efficiency in
impinging jet flow geometry. The results indicate that the particle trajectories and deposition
efficiencies are increasingly affected by surface charge heterogeneity as one moves radially away
from the stagnation point.
2-24
Capturing the Essence of Deposition Phenomena: Random Sequential Adsorption and
Related Models
JULIAN TALBOT, Department of Chemistry and Biochemistry, Duquesne University,
Pittsburgh, PA, talbot@duq.edu
Although it is often the first thing that comes to mind in describing adsorption and deposition
phenomena, the Langmuir model usually provides a poor description of the deposition of
macromolecules and colloidal particles on solid surfaces. The deposition process in these cases is
often irreversible and, in order to obtain an accurate description, it is necessary to account for
surface exclusion effects and the transport mechanism of the depositing particles to the
interfacial region. It is the purpose of this talk to review the rather remarkable progress that has
been made during the last fifteen years towards the goal of a quantitative description of
adsorption/deposition processes on solid surfaces.
The paradigm for the recent advances is, unquestionably, the Random Sequential Adsorption
(RSA) model. Originally conceived to describe the packing of coal, this model accurately
describes the blocking effects of the pre-deposited particles in an irreversible deposition process.
The structure of the deposited particle configuration differs fundamentally from an adsorbed
equilibrium fluid, although the difference can be negligible at low to medium densities. The
basic model and its predictions for a single component, mixtures, non-spherical particles and
macromolecules undergoing post-adsorption conformational changes will be reviewed. We also
show how it can describe adsorption on a heterogeneous surface (the Random Site Model). In
view of its rather simplistic representation of the transport process, RSA describes a variety of
experimental data with surprising accuracy. The reasons for this fortuitous result will be
discussed.
Larger particles may be strongly influenced by gravity as they deposit and in this case a different
model is required. For situations in which gravity plays a dominant role and the particle
trajectories are deterministic, the Ballistic Deposition (BD) model is appropriate. A new feature
that emerges in this model is the presence of connected clusters of particles, even at low surface
coverages. Processes that are intermediate between BD and RSA, which may be characterized by
a single parameter, can also be described.
2-25
Embedding of phospholipid vesicles into exponentially growing polyelectrolyte multilayers:
A new way to surface immobilized nanoreservoirs and nanoreactors
Marc Michel1,2, Guillaume Fleith2, Jean-Claude Voegel1, Pierre Schaaf2, VINCENT BALL1,
1
Institut national de la Santé et de la Recherche Médicale, Unité 595, Faculté de Médecine, 11
rue Humann, 67085 Strasbourg Cédex, France, 2Centre national de la Recherche scientifique,
Institut Charles Sadron, 6 rue Boussingault, 67085 Strasbourg Cédex, France,
vincent.ball@medecine.u-strasbg.fr
Polyelectrolyte multilayers (PEMs) appear more and more as versatile tools to functionalize solid
liquid-interfaces. Indeed, proteins with their native conformation, DNA, and quantum dots have
been embedded in such films. An other functionalization strategy consists in adsorbing
covalently modified polyelectrolytes and also stimuli responsive and hydrolysable
polyelectrolytes. In this communication we present a method to embed intact (polyelectrolyte
stabilized) phospholipid vesicles into PEMs. Two ways of deposition will be described : either
by the dipping method or by spray pulverisation. The build up of the architectures was
characterized by means of quartz crystal microbalance with dissipation, atomic force microscopy
and ellipsometry. The molecular integrity of the vesicles was studied by encapsulation of
Fe(CN)64- into the vesicles before embedding and monitoring of the ferrocyanide release from
the functionalized PEM by means of cyclic voltametry on the surface of gold electrodes. The
spray pulverisation method offers the advantage of faster and easier deposition. We will also
present the embedding of two stages of vesicles into the PEMs containing two kinds of
encapsulated molecules.
2-26
Preparation of self-assembled nanostructures using colloidal chemistry
FREDERIC JUILLERAT, Paul Bowen, Heinrich Hofmann, Powder Technology Laboratory,
Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (Swiss Federal Institute of
Technology), EPFL, CH-1015 Lausanne, Switzerland, frederic.juillerat@epfl.ch
Nanomaterials offer a wide ranging novel applications encompassing electronics, materials
sciences, medical sciences and engineering. However, many of these applications require an
organization of such materials into various ordered structures. Self-assembly processes that are
driven mainly by competing molecular interactions like hydrophobic versus hydrophilic
components, gravitational, van der Waals or coulombic interactions, amongst others, have been
shown to have the potential of achieving complex structures, from 0D to 3D. For that aim, basic
contributions to the self-assembly phenomenon, such as particles-particles and particles-substrate
interactions, capillary forces, particle diffusion, must be understood and controlled.
In the present work, silica and gold particles smaller than 100nm have been assembled in various
ordered structures. Three-dimension colloidal crystals with ordering lengths of tens of m have
been obtained by drying highly concentrated silica suspensions on flat substrates or by using dipcoating. Two-dimensional ordered monolayers of nanoparticles have also been produced by
evaporating the solvent of suspensions of adapted pH, ionic strength and particle concentration.
Dip-coating furthermore allowed the production of micrometers-long chains of particles with
diameters between 50 and 15nm using topographically nanopatterned substrates, prepared by Xray Interference Lithography which guides the assembly process. Substrates patterned with holes
combined with dip-coating can lead to ordered arrays of single dots over tens of m. The forces
involved during both self-assembly and guided-assembly processes arise notably from
dispersion, capillary and adhesion forces. Theoretical analyses based on existing models have
been performed for each assembled system to establish the relative importance of these
contributions as a function of the most relevant experimental parameters.
2-27
Interpretation of the stability of water-in-oil emulsions based on adsorption phenomena at
oil/water interface
L. GOUAL, G. Horvath-Szabo, J. H. Masliyah, University of Alberta, Department of Chemical
and Materials Engineering, Edmonton, AB, Canada, lgoual@ualberta.ca
Adsorption of bituminous components from heptane/toluene mixtures at oil/water and oil/gold
interfaces was measured in situ by a Quartz Crystal Microbalance. The adsorption kinetics
follows two distinct regimes depending on bitumen concentration. At low concentration
(<1.5wt%), an unsteady irreversible adsorption at oil/water interface manifests in the form of a
slow and continuous build-up of asphaltenes with minor resins into multi-layers. At high
concentration, a steady adsorption with limited reversibility is measured where saturation is
reached after formation of a monolayer composed of asphaltenes with major resins. The
concentration regimes are determined by the resin-to-asphaltene ratio in the bulk phase. The
rigidity of oil-water interface at low bitumen concentration is related to the rigid network formed
by sterically non-stabilized asphaltenes. In this regime, formation of asphaltene bridges between
water drops destabilize the emulsions against flocculation, thus dewatering of bitumen froth is
easy. However at high bitumen concentration, in the steady regime, water-in-oil emulsions are
kinetically stabilized against flocculation by sterically stabilized asphaltene layers, and
dewatering of bitumen froth becomes difficult.
2-28
Anisotropic Adsorption of Molecular Assemblies on Inorganic Surfaces
J. CHUN1, J.-L. Li2, R. Car2, I. A. Aksay1, D. A. Saville1, 1Princeton Center for Complex
Materials and Department of Chemical Engineering, Princeton University, Princeton, NJ,
2
Department of Chemistry, Princeton University, Princeton, NJ, jchun@Princeton.edu
Oriented adsorption of rod-like molecular assemblies on inorganic surfaces is analyzed in terms
of anisotropic van der Waals interactions between an assembly and the substrate.
The van der Waals interaction is calculated using a Lifshitz methodology using the anisotropic
properties of the crystalline substrate derived from a first principles computation of the dielectric
response function for graphite. It is shown that, provided the assembly is sufficiently large, a
small amount of substrate anisotropy provides torque that overcomes rotational Brownian motion
near the surface. The probability of a particular orientation is computed by solving a
Smoluchowski equation that describes the balance between torque and Brownian forces. The
results show that the torque aligns both cylindrical micelles and protein fibrils. In the systems
studied here, the interaction energy is a minimum when the assembly lies perpendicular to a
symmetry axis of a crystalline substrate. These results agree with experiments with both
cylindrical and hemi-cylindrical micelles and proteins adsorbed on crystalline graphite.
2-29
Monoparticle films of gold nanorods formed at a liquid-liquid interface
Y. NIIDOME, M. Yamaguchi, S. Yamada, Department of Applied Chemistry, Kyushu
University, Fukuoka, Japan, ynidotcm@mbox.nc.kyushu-u.ac.jp
We have found that a monoparticle-film of gold nanorod (NRs) could be formed at a liquidliquid interface of hexane and water. In this study, we characterized the optical properties of the
monoparticle-films of NRs that were transferred onto glass substrates. In a phase-separated
solution, 20 mL of the NRs solution and 10 mL of hexane, acetonitrile (5 mL) was vigorously
injected. A monoparticle-film formed at the liquid-liquid interface was transferred onto a glass
plate that was vertically lifted up through the interface.
Scanning electron microscopic images of the monoparticle-film of NRs showed that there are
few stacked particles in the film. It is known that a NRs solution shows two clear absorption
peaks in visible (~520 nm) and near-IR (~800 nm) regions; however, the spectra of the deposited
films show no clear absorption peaks. The peak profiles of deposited films prepared from
different concentrations of NR solutions were almost independent of the concentration of NRs.
This indicates that the deposited NRs form two-dimensional aggregates on the substrates. Degree
of the aggregation was changed by additional amphiphilic molecules, for example,
phosphatidylcholine in acetonitrile.
3A-01
Brownian motion in the presence of temperature gradients: An extension of Einstein’s
theory on the 100th anniversary of its formulation
HOWARD BRENNER, Department of Chemical Engineering, MIT, Cambridge, MA,
hbrenner@mit.edu
Einstein’s theory of Brownian motion, which addresses only isothermal fluids, is here extended
to situations in which the fluid is subject to an externally-imposed temperature gradient. This
extension involves adding a temperature-gradient animated “drift velocity” U to the usual
diffusive Brownian contribution appearing in the Fokker-Planck equation governing the
particle’s conditional probability density. Remarkably, this drift velocity, tending to cause the
particle to move towards colder regions of the fluid, is an innate molecular property solely of the
solvent in which the Brownian particle is dispersed. Explicitly, U is independent of the Brownian
particle’s size and shape, as well as of its physicochemical properties. As such, the drift velocity
is exactly the same for a macroscopic particle as it is for a molecule of the solvent itself. The
underlying theory is supported by experimental thermophoresis data. The ansatz underlying our
theory is derived by elementary sedimentation-equilibrium-type arguments of the type invoked
by Einstein in his 1905 paper. Here, however, instead of an external force-animated chemical
potential gradient causing the Brownian particle’s drift, the animation is now caused by the
temperature gradient. Consequences of our theory, involving fundamental modifications of the
Navier-Stokes and energy equations for nonisothermal fluids, are discussed. (200 words, exactly)
3A-02
Molecular dynamics simulations of nanodrop motion on uniform and non-uniform surfaces
SP. S. SARAVANAN, J. B. McLaughlin, R. S. Subramanian, Department of Chemical
Engineering and Center for Advanced Materials Processing, Clarkson University, Potsdam NY, ,
suppiahs@clarkson.edu
Results for the motion of nanodrops on solid surfaces will be presented. The results were
obtained from molecular dynamics (MD) simulations of drops moving on crystalline solid
surfaces. Two driving forces were considered: body forces and wettability gradients. The results
indicate that hydrodynamic drag is negligible compared to contact line resistance for drops in the
size range considered. A modification of the Blake-Haynes theory was used to model the results
of the MD simulations. To obtain values for the Blake-Haynes contact line friction coefficient,
MD simulations of drops spreading on uniform surfaces were performed for uniform surfaces
having a broad range of wettabilities. In addition, results for the friction coefficient were
obtained for receding contact lines. It was found that the friction coefficient for a receding
contact line is significantly larger than the friction coefficient for an advancing contact line. The
discrepancy between the friction coefficients for advancing and receding contact lines increases
rapidly as the surface wettability increases. Since the Blake-Haynes theory makes no distinction
between advancing and receding contact lines, a modification of the theory is needed. The
modified theory agrees well with the MD results for drop motion on both uniform surfaces and
surfaces with wettability gradients.
3A-03
Effects of extreme confinement and field history on the self-assembly of
magnetorheological fluid colloids
R. HAGHGOOIE, P. Doyle, Department of Chemical Engineering, Massachusetts Institute of
Technology, Cambridge, MA , rhaghgoo@mit.edu
The characteristic length scales found in microfluidic devices have been shrinking drastically
over the past several years. As a result it is becoming increasingly important to study the effects
of this tight confinement. We have used the Brownian Dynamics simulation technique to study
the self-assembly of magnetorheological (MR) colloids under confinement. We have examined
the effects of extreme confinement (on the order of the size of the MR colloids) and observed
that the confinement can induce some very interesting structural properties that deviate from
those observed in systems with much less confinement. These deviations manifest themselves in
the size of clusters that form as well as the average spacing between the clusters. Additionally
we have determined the effects of field history upon the self-assembly of the MR colloids. We
have shown that the manner in which the magnetic field is applied can have a significant impact
upon the structure as well.
3A-04
Self-Organization of Amphiphilic Copolymers in Aqueous Media
F. M. WINNIK, Department of Chemistry and Faculty of Pharmacy, Université de Montreal,
Pavillon J. A. Bombardier, CP 6128 Succursale Centre Ville, Montreal, QC, Canada,
francoise.winnik@umontreal.ca
The assembly of polymers in water is controlled by various extrinsic factors, such as solution
temperature, pH, ionic strength and the presence of additives, but it depends primarily on the
chemical composition of the polymer and on the sequence of monomer units. Means to direct the
assembly of amphiphilic polymers in water will be demonstrated using as examples various
copolymers N-isopropylacrylamide (NIPAM). Of particular interest are telechelic PNIPAM
samples of narrow polydispersity prepared by controlled free radical polymerization (RAFT).
These polymers assemble in various modes depending on solution concentration and
temperature. Their properties in water in the dilute regime were examined by microcalorimetry,
light scattering, fluorescence spectroscopy and rheological measurements The properties of
telechelic PNIPAMs will be compared to those of sample bearing a few hydrophobes in the
middle of the chain, rather than at the chain ends, and to those of telechelic poly(ethylene oxides)
of similar sizes.
3A-05
Structure of Microparticles and Nanoparticles in Solid-Stabilized Emulsions
Sowmitri Tarimala,* Chihyuan Wu,* Renu Sharma**, LENORE L. DAI*, Department of
Chemical Engineering, Texas Tech University, MS 3121, Lubbock, TX, **Center for Solid State
Science, Arizona State University, Tempe, AZ
Emulsions of oil and water stabilized by adsorbed solid particles are known as solid-stabilized
emulsions (often referred to as Pickering emulsions). Using confocal microscopy and
environmental transmission electron microscopy, we have studied the self-assembly of colloidal-
sized polystyrene particles and alkanethiol-capped silver nanopaticles in Pickering emulsions.
Colloidal samples of monodisperse size, when exposed to the emulsion at low concentrations,
were found to form small patches with local hexagonal order; these crystalline domains were
separated by other particle-free domains. Polystyrene particles with different sizes (1 micron and
4 microns) and different wettability could simultaneously segregate to the emulsion interface and
form mixtures on it. In contrast to microparticles, the dodecanethiol-capped silver nanoparticles
of 1-5 nm form randomly distributed multilayers at the liquid/liquid interface, with an
interparticle distance varying from close contact to approximately 25 nm. Our work offers the
first direct observation of nanoparticles in a liquid medium using the environmental transmission
electron microscope (E-TEM).
3A-06
Creating Polymeric Nanostructured Networks Through Nucleation and Growth Strategy
JUN-YING XIONG1, Xiang-Yang Liu2, Da-Wei Li2, Janaky Narayanan2, Shing Bor Chen1, TaiShung Chung1, 1Department of Chemical and Biomolecular Engineering, National University
of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore. 2Department of Physics,
National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore,
g0202005@nus.edu.sg
The new season of the material science is beginning. For material scientists, the task of
reassembling basic elements now is shifting focus from as-synthesized nanoparticles (first
generation) and their single-component assemblies to particles derived from the first-generation
ones and supracrystals of different particles. However, nucleation and growth approach, which
serves as one of the key strategies to achieve this goal, still remains more like an art than a
science. It is the purpose of this study to make a step-forward progress in the quantitative
understanding of complex nucleation and growth systems and to use the new knowledge
obtained to shed some light on how to use nucleation and growth strategy to fabricate desired
nanostructured materials. In this presentation, agarose gelation is used as the typical example.
Agarose is a repetitive, essentially uncharged, marine polysaccharide. In the sol state gyration
radius of agarose molecules can be as large as ~ 50 nm and behave like typical colloidal
particles. In the presentation, kinetics as well as the evolution of the agarose gel topology is
elucidated, and the agarose gelation mechanism is identified. It is found that the gelation process
can be clearly divided into three stages: induction stage, gelation stage, and pseudo-equilibrium
stage. The induction stage of the gelation mechanism is identified using an advanced rheological
expansion system (ARES, Rheometric Scientific). It was found that gelation turns out to occur
through a nucleation and growth mechanism with a well-defined induction time. The relationship
between the induction time and the driving force (supersaturation) follows the 3D nucleation
model. A schematic representation of the three stages of the gelation mechanism is given based
on in situ turbidity and rheological measurements. Further analysis of the kinetics data using 3D
nucleation theory indicates that supersaturation driven mismatching between agarose fibrils plays
a crucial role in promoting branching, which is extremely important in the network formation.
Molecular simulation is employed to support and visualize the proposed interpretation. Based on
the knowledge obtained, some comments for building the second-generation nanostructured
materials are given.
3A-07
Preparation and Small Angle Neutrons Scattering Characterization of Polysiloxane – silica
Nanocomposites
M. MEYER1, C. Parneix1 J. Persello1, B. Cabane 2, R. Schweins 3, 1 LCMI, Université de
Franche-Comté, 16 route de Gray; 25030 Besançon, France. 2 PMMH, CNRS UMR 7636,
ESPCI, 10 rue Vauquelin, 75231 Paris cedex 05, France. 3 ILL, BP 156, 38042 Grenoble cedex 9,
France. michael.meyer@univ-fcomte.fr
The incorporation of filler into elastomers imparts many interesting and useful properties to the
particle filled composite material. It is well known that the properties mainly depends on the
dispersion condition of filler particles and their principal relevant properties : particle size,
surface area, filler surface chemistry and on rubber filler interactions.
In the present work, we used Small-Angle Neutron Scattering (SANS) experiments to study the
phase transitions in the structure of a composite material made of surface modified silica
nanoparticles dispersed in silicone rubber. Self assembling concepts are used in order to explain
the role of the silica-rubber and silica-silica interactions on the positioning of silica nanoparticles
in three dimensional structures. The phases of interest are the disordered "silica domain" and the
long range correlated "fractal silica network".
We investigate again by SANS, whether the fractal network undergoes deformation,
reorganization, or breaks at large strains, and correlate the scattering patterns to the mechanical
properties of the filled rubber.
From a practical point of view, this presentation is concerned with investigations using model
polysiloxane elastomers and silica nanoparticles systems to experimentally elucidate the role of
the silica size and surface modification on the long range structure of the silica network.
3A-08
Continuous Polyelectrolyte Nanofilm Growth under an Applied Electric Potential
A. PASCAL NGANKAM, Paul R. Van Tassel, Dept. of Chemical Engineering, Yale University,
New Haven, CT
Polymer nanofilms offer facile control over the physical, chemical, and biological character of a
material surface. Adsorption from solution is a simple means of fabrication, but control over film
thickness is limited due to rapid saturation. Thicker, multilayer films are possible, but only
through many alternate exposures to solutions of complementary species. We show here that a
modest electric potential applied between an adsorbing substrate and a counter-electrode, in the
presence of a polyelectrolyte solution, can lead to nanofilm growth that is continuous, without
apparent saturation; films of arbitrary and controllable thickness may thereby be realized in a
single step. We observe this behavior for poly-L-lysine onto indium tin oxide, at substrate
potentials exceeding a threshold (Vth), where 0.5 V < Vth < 0.6 V (relative to a standard
hydrogen electrode), using optical waveguide lightmode spectroscopy (OWLS). Film growth
kinetics are initially very rapid and subsequently become linear with time. Linear growth may
even be re-established following interruption by placement of a protein layer, suggesting
possible applications in biosensing and bioelectronics. Films grown under an applied electric
potential exhibit very modest desorption, but are somewhat unstable to removal of the potential.
Chemically cross-linking films using the EDC/NHS method results in greatly improved stability.
Atomic force microscopy images reveal films to be particulate, with the particle size slightly
exceeding the polymer's hydrodynamic diameter. We find no evidence of electrochemical
oxidation at the adsorbing surface, and suspect that secondary structure formation may play a
role in the observed behavior.
3A-09
Structure and dynamics of fluorinated fatty acid SAMs by solid-state NMR
ANDREW O’DONNELL and Linda Reven, McGill University, Montreal, QC, Canada,
andrew.o.donnell@mail.mcgill.ca
The bonding and chain dynamics of fatty acid monolayers on metal oxides have been previously
characterized in detail by solid-state NMR techniques. This current study investigates the
structure and molecular dynamics of monolayers of both perfluorinated and semi-fluorinated
fatty acids, self-assembled on powdered ZrO2 surfaces. Self-assembled monolayers (SAMS)
have been prepared of perfluorinated fatty acids on ZrO2 nanoparticles, with chain-lengths
ranging from 8 to 18 carbons. The series of semi-fluorinated alkanoic acids
F(CF2)m(CH2)nCOOH, with m = 5, 7, 9 and n = 10, 16, 22 have been synthesized and the
monolayers on ZrO2 prepared. All SAMS have been studied by 19F-MAS NMR and 13CCPMAS using variable temperature and relaxation techniques. PAS-IR spectra have also been
collected for comparison with the NMR data.
3A-10
Dynamic NMR Investigation of Lipid-Hydrotrope Interaction in a Homogeneous System
NICOLE HELDT, Fadwa Odeh, Yuzhuo Li* Department of Chemistry and Center for Advanced
Materials Processing, Clarkson University, Potsdam, NY, yuzhuoli@clarkson.edu
It has been reported in our previous study that a homogeneous phase (L1) can be obtained by
mixing an appropriate ratio of hydrotrope and lipids. This microemulsion region can be used to
prepare unilamellar vesicles by dilution with an aqueous media. It has also been shown that
vesicle size is proportional to the lipid/hydrotrope ratio, where the addition of hydrotrope to
these systems affects the curvature of the vesicles that form. The nature of lipid/hydrotrope
interaction in the L1 phase is important to understanding the vesicle formation mechanism, so as
to facilitate the control of the physical and chemical properties of synthesized vesicles
In this study, the L1 phases for lipid/hydrotope/water systems were systematically investigated
using dynamic NMR method. More specifically, NMR T1 relaxation times are measured for the
L1 systems made of various hydrotropes with lipid/hydrotrope molar ratios. Among the
hydrotropes studied, the discussion will be focused on sodium xylene sulfonate (SXS), sodium
cumene sulfonate (SCS), and sodium toluene sulfonate (STS). Due to their structural difference,
it is anticipated that the degree of interaction between the hydrotrope and lipid varies.
Furthermore, it is hypothesized that subtle differences in lipid-hydrotrope interactions stem from
structural variations in the hydrotopes and their ability to solubilize various lipids. This in turn
influences physical and chemical properties of the vesicles.
In this talk, some background information on the use of the L1 phase to prepare vesicles will be
presented first. The experimental results obtained using dynamic NMR methods including spinlatice relaxation time measurement will be discussed, especially the correlation between the
hydrotrope structure and the lipid-hydrotrope association within the L1 phase. The potential
implication of such variance in lipid-hydrotrope interaction on the vesicle formation mechanism
will be speculated.
3A-11
NanoLab: a Hands-On Introduction to Nanoscience for Scientists and Engineers
M. B. Johnson, L. A. BUMM, Center for Semiconductor Physics in Nanostructures, Department
of Physics and Astronomy, University of Oklahoma, Norman, OK, bumm@nhn.ou.edu
We have developed a sophomore level laboratory course in nanotechnology. We have taken this
hands-on approach to introduce students to the concepts used in nanotechnology much earlier
than they would see them in them in the standard curriculum. Although sophomore level
students do not generally have the background to understand the full theoretical explanation of
all the phenomena, they do take with them a basic understanding that can serve as a framework
for appreciating the broader issues when they encounter them in later courses. Topics we have
covered are: crystal structure, x-ray diffraction, electron microscopy, electron microprobe,
spectrophotometry, extinction, light scattering (Rayliegh & Mie), microfluidics, scanned probe
microscopy, and thin-film growth. A report of our experience will be presented.
3A-12
Porous Photopolymer Photonic Bandgap Structures: Fabrication and Applications
ALEXANDER N. CARTWRIGHT, Institute of Lasers, Photonics and Biophotonics, Department
of Electrical Engineering, State University of New York at Buffalo, NY
Significant research efforts have been focused on the development of effective means for
detecting organic molecules optically using porous one-dimensional photonic bandgap
structures. To date, most such work has been based on porous silicon microstructures, which are
typically created using a controlled electrochemical etching process in a hydrofluoric acid
solution. Generally, these sensors rely on changes in the optical resonance that occurs when the
porous structure is occupied by the analyte species, allowing for simple and effective optical
detection schemes. Here, we present a simple method for the production of polymeric Bragg
reflection gratings containing periodic porous layers, and we demonstrate optical detection of
organic solvent vapors using these structures. To create the structures, a pre-polymer syrup
containing a monomer, a photoinitiator, a co-initiator, liquid crystals (LC), and non-reactive
solvent (acetone or toluene) is sandwiched between two pieces of glass, and the periodic
structure is then formed by applying an optical interference pattern generated using a simple onebeam setup. We demonstrate that a few different vapors can penetrate the porous structure and
effects a change in the effective refractive index of these gratings, inducing a shift in the
reflection wavelength. This shift is pronounced, and can easily be observed by eye, or detected
by optical means. We also demonstrate that this shift depends on the vapor concentration, and
can be used to reversibly and repeatedly detect the vapor’s presence. In addition, we show that
the addition of aminosilane to the pre-polymer syrup improves the stability of the resulting
gratings, suggesting that this photopolymer fabrication technique could be used to create
structures suitable for biological applications in aqueous environments.
3A-13
Design and Study of Structured Polymer Microspheres
G. Gao, M. Srivastava, N. Burke, R. Takekoh, A.P. Hitchcock, H.D.H. STOVER, Department of
Chemistry, McMaster University, Hamilton, ON, Canad, stoverh@mcmaster.ca
Multi-layer microspheres may be formed by controlled thermal or chemical imprinting during
the particle formation. Specifically, thermal oscillations imposed on precipitation
polymerizations of divinylbenzene can be made to produce matching radial density profiles
within the microspheres. In this way, onion-type microspheres having up to 20 nested layers may
be produced. Similarly, chemical doping of the growing microspheres with suitable comonomers
results in distinct layers enriched in functional comonomer. Phenylmaleimide and itaconic
anhydride are examples of reactive comonomers that tend towards alternating incorporation and
hence form well-defined shells. These comonomers can be used for subsequent shell-specific
chemical functionalization of these spheres. The chemical composition of the resulting oniontype microspheres are quantitatively mapped using Scanning Transmission X-ray
Microspectroscopy (STXM). Possible applications of these structured polymer microspheres
with controlled porosity and functionality as building blocks for 3D photonic band gap devices,
and catalyst supports will be discussed.
3A-14
Aggregation in thermosensitive copolymers and related applications
X. X. ZHU, M. Nichifor, H.Y. Liu, D. Avoce, Département de chimie, Université de Montréal,
C. P. 6128, succursale Centre-ville, Montréal, QC, Canada, Julian.Zhu@umontreal.ca
Some water-soluble natural and synthetic polymers can form hydrophobic aggregates and phaseseparate when the temperature is raised. This change can occur at a sharp temperature, known as
the lower critical solution temperature (LCST), or over a range of temperatures, depending on
their chemical structures and composition. We have found that thermosensitive polymers
incorporating natural amphiphilic compounds such as bile acids can even manifest a two-stage
aggregation behavior. This can be very useful because of its rheological and technological
implications and potential biomedical and industrial applications. We have made several series
of copolymers with comonomers such as N-substituted acrylamides, bile acid derivatives and
even styrene. We found that a small amount of styrene can lower significantly the LCST of the
copolymers. A stable emulsion can be formed for such polymers, and they are useful as
reversible flocculants and dispersants. The aggregation of the acrylamide copolymers can be
facilitated by the presence of the bile acid residues, which can also form micelles with added
surfactants. Thermosensitive copolymers are also used as solid support and scavengers in organic
synthesis, making the separation process easier.
3A-15
One-pot Synthesis of Block Copolymer Coated Cobalt Nanocrystals
GUOJUN LIU, Xiaohu Yan, Zhihua Lu, Scott A. Curda, Jyotsana Lal, Department of Chemistry,
Queen’s University, 90 Bader Lane, Kingston, ON, Canada, gliu@chem.queensu.ca
Reported in this paper is the preparation of -Co nanocrystals coated by a monolayer of
poly(acrylic acid)-block-polystyrene or PAA-PS. This method, characterized by its convenience
and potential to yield particles with narrow size distributions, is adopted from one using oleic
acid as the surfactant. The replacement of oleic acid by PAA-PS as the surfactant during Co
nanoparticle preparation yields Co/PAA-PS particles that can be solvent-cast to yield
mechanically robust bulk films or 2-d ordered Co particle arrays. For the multi-dentate nature of
the PAA binding block, the PAA-PS coating is resistant towards solvent rinsing. The thickness
of the coating can be increased by increasing the length of the PS block. Such Co nanoparticles
may have many potential applications.
3-16
Passivating Quantum Dots using Polymers
T. E. Dykstra, J. K. Oh,, X.-S. Wang, M. A. Winnik, G. D. SCHOLES, Department of
Chemistry, University of Toronto, Toronto, ON, Canada, gscholes@chem.utoronto.ca
The molecules at the surface of a semiconductor nanocrystal must fulfil a dual role. In addition
to passivating the surface, they must provide an interface compatible with processing and
integration steps in manufacturing. For example, water-soluble surface ligands are needed for
biological labeling; an electrically conductive layer would be ideal for solar cells; and a
polymerizable surface is needed to make photoluminescent polymer composites. A current
strategy for meeting these objectives is to replace the ligands introduced during quantum dot
synthesis with new ligands, i.e., ligand exchange. We will describe a new approach: use of a
multidentate polymer ligand, such as polydimethylaminoethylmethacrylate (PDMAEMA), to
modify the surface of CdSe and CdSe/ZnS core-shell colloidal quantum dots. We have found
that adsorption of PDMAEMA is accompanied by release of troctylphosphine oxide surface
ligands, the process is free of agglomeration, and the modified nanocrystals become soluble in
methanol. The photoluminescence properties are well preserved in either toluene or methanol.
The polymeric ligands have the following advantages: (a) As-prepared QDs can lose colloidal
stability via loss of small molecule ligands that provide only a single binding group
(monodentate ligands) to the particle surface. Polymers with many binding groups (multidentate
ligands) such as PDMAEMA are significantly more stable to dissociation. (b) The polymer
replaces a surface-bound monodentate ligand in dilute solution with high efficacy. (c) The
polymer can be functionalized so as to modify the colloidal properties of the QDs.
3A-17
New approach to reflective type electrochromic display and the effect of particle size on the
color efficiency and switching time
JEE-HYUN RYU, Kyung-Do Suh, Division of Chemical Engineering, College of Engineering,
Hanyang University, Seoul 133-791, Republic of Korea, kdsuh@hanyang.ac.kr
Reflective type electrochromic display (R-ECD) based on the viologen-modified polymeric
microspheres was proposed, and the influence of particle size on the electro-optical
characteristics was investigated. At first, the functionalized polymeric microspheres were
produced through the seeded polymerization, and then viologen moieties were refluxed on the
surface in toluene. In order to control the diameter of viologen-modified polymeric
microspheres, the size of polystyrene seed particles was altered using the solvency of medium
during the dispersion polymerization. It was confirmed that the color efficiency and switching
time of R-ECD were depended largely on the size of polymeric microspheres due to their
specific surface area. The particle size and morphology were monitored utilizing an optical
microscope (OM), and a scanning electron microscope (SEM), respectively. Redox reactions of
the R-ECD were examined by cyclic voltammetry. Reflectance of the R-ECD cell was observed
by a spectrophotometer. Response times were recorded using a white LED array
spectrophotometer in combination with a digital multimeter.
3A-18
Molecular stars with a three-fold or a six-fold rotation symmetry: Self-assembly and
Luminescence
SUNING WANG, Wen-Li Jia, Corey Seward, Qinde Liu, Department of Chemistry, Queen’s
University, Kingston, ON, Canada
Two classes of molecule star molecules have been synthesized and investigated by our group.
The first class has an approximate C3 symmetry with three substituent groups attached to either a
benzene, a triazine, or a three-coordinate boron central core. The second class has an
approximate C6 symmetry with six substituent groups attached to a central benzene core. The
substituent group in both classes is functionalized by either 2,2’-dipyridylamino, 7-azaindolyl, or
2-(2’-pyridyl)benzimidazolyl, which allows further functionalization of the star molecules by
metal ions. These two classes of molecules display diverse structures in solution and the solid
state. Nanowires formed by self-assembly of some of the 6-fold star molecules have been
observed on a graphite surface. The luminescent properties of these molecules are highly
dependent on the nature of the functional group and the metal ions present. Some of these
molecules have been found to be useful as luminescent sensors for a certain organic analytes.
The details of syntheses, structures, luminescent properties of the star molecules and their
applications will be presented.
3A-19
Routes of Molecular Energy Transfer over Self-Assembled Surfactant Interfaces
T.D. Sechler, J.C. DEAK, Department of Chemistry, University of Scranton, Scranton, PA,
deakj2@scranton.edu, Y. Pang, Z. Wang, and D.D. Dlott, Department of Chemistry, University
of Illinois, Urbana, IL
The intermolecular contacts by which molecular energy is transported across a surfactant
interface are observed via IR-Raman spectroscopy. In this technique, an IR light pulse is used to
initiate a specific molecular vibration near the interface, e.g. the O-H stretch of a water molecule
in a reverse micelle. Following this nascent excitation, time delayed anti-Stokes Raman
spectroscopy is used to follow the transfer of the vibrational energy across the surfactant
interface as it is passed from water to the surfactant polar group, to the tail region, and lastly to
the nonpolar fluid. Data is presented on CCl4/AOT/H2O reverse micelles following independent
excitation of water O-H stretch or surfactant C-H stretch. OH excitation reveals energy
relaxation of multiple water structures near the interface. Subsequent OH relaxation is strongly
coupled to sulfonate vibrational modes of the surfactant head group. The relaxation continues
with the sequential movement of energy through the surfactant tail and then into the nonpolar
phase. Following CH excitation energy is quickly redistributed among the surfactant head and
tail vibrations before it is eventually transferred to the nonpolar phase.
3A-20
Microwave synthesis and applications of semiconductor, metallic and magnetic
nanoparticles
FARID BENSEBAAa, Andrea Firtha, Natasha Patritoa, Chrisitna Bock, Yvon Le Page, Pascal
L’Ecuyer, Dashan Wang, Florin Zavalicheb, Teodor Veresb, aInstitute of Chemical Process and
environmental Technology, National Research Council of Canada, 1200 Montreal Rd, M-12,
Ottawa, ON K1A 0R6 Canada, bIndustrial Materials Institute, National Research Council of
Canada, 75 de Mortagne Blvd., Boucherville, Canada, farid.bensebaa@nrc-cnrc.gc.ca
For numerous reasons, there is a growing interest in using alternative and scalable approaches for
the synthesis of nanoparticles. Among these approaches, microwave synthesis has received a
growing interest lately. Microwave synthesis has been shown not only to enhance the rate of
chemical reactions, but also to give better yields in some cases. Our group has recently applied
this approach to prepare semiconductor, metallic and magnetic nanoparticles for specific
applications [1-3]. Two specific cases will be discussed. First we will discuss the synthesis and
characterisation of alloyed Pt-Ru nanoparticles. The integration of these nanoparticles in a
polymeric matrix and their catalytical properties for DMFC (Direct Methanol Fuel Cell)
applications will be also presented. In the second case, semiconductor nanoparticle preparation
and characterisation will be shown. Their utilization for photovoltaic applications will be also
discussed.
3A-21
Direct Laser Micro-Patterning of Self Assembled Monolayers
M. Reza Shadnam, ALIDAD AMIRFAZLI, Department of Mechanical Engineering, University
of Alberta, Edmonton, AB, Canada, a.amirfazli@ualberta.ca
The ability to engineer surface properties (e.g. wettability, adhesion) at micoscopic scale is the
key to the emerging technologically important areas such as biosensors, tissue engineering,
MEMS, and controlled delivery of liquids in microfluidics. A “Direct Laser Patterning” (DLP)
methodology has been developed to manipulate surface wetting properties using a chemisorbed
self assembeled monolayer (SAM) on gold film (alkenethiol type). This talk will provide an
overview of the DLP methodology. It will also report on kinetics of SAM desorption using curve
fitting of experimentally measured SAM coverage data at different temperatures to Eyring
equation. Activation energy of SAM desorption is calculated to be 30 kcal/mol in air. This
information is used in a recently developed thermokinetics model, which describes laser induced
desorption of SAMs through combining SAM desorption kinetics equation with heat propagation
equations in DLP methodology. It was found that contrast plots of experimental scanning
electron microscopy (SEM) images, which is correlated to surface coverage of SAMs desorbed
after laser irradiation, agreed with the theoretically predicted surface composition of SAMs. The
surface composition of SAM was then interpreted in terms of the wetting property of the
resulting surface. The effect of incident laser beam power and size on final spatial coverage of
SAMs on the surface and feature sizes was investigated both experimentally and by modeling.
Considering the correlation of the theoretical and experimental results we concluded that the
feature sizes are controllable in a predictable way (using the presented thermal-kinetics model)
through varying laser beam power and beam size.
3A-22
Preparation of refined Gold nanorods : synthesis, shape separation and optical properties
KYOUNGWEON PARK1, Vivek Sharma1, Mostafa A. El-sayed2,3, Mohan Srinivasarao1,2,
1
School of Polymer, Textile and Fiber Engineering, 2School of Chemistry and Biochemistry,
3
Laser Dynamics Lab, School of Chemistry and Biochemistry, Georgia Institute of Technology,
Atlanta, GA
Nanoparticle synthesis is characterized by a polydispersity in the shape and size of particles.
Since the shape and size determine the properties and applications of nanoparticles, the synthesis
of uniformly shaped particles and the separation of desired shape and size from a mixture of
different shapes and sizes are necessary. We describe improved seed mediated synthesis of gold
nanorods producing a high yield of nanorods with low polydispersity. By understanding the
hydrodynamics of nanorods and nanospheres undergoing centrifugation, the efficient separation
of gold nanorods from mixture of shapes was achieved. The optical properties of resulting
refined gold nanorods are compared to predictions of existing theories, and the main parameters
affecting them such as particle size and shape or the dielectric properties of the environment are
discussed.
3A-23
Lattice Boltzmann simulations of drop migration on surface with wettability gradient
XINLI JIA1, J. B. McLaughlin1, Goodarz Ahmadi2, 1Department of Chemical Engineering,
2
Department of Mechanical and Aeronautical Engineering and Center for Advanced Materials
Processing, Clarkson University, Potsdam NY, jiax@clarkson.edu
This talk will present results for drop migration on solid surfaces with wettability gradient and
chemical roughness. The simulation results were obtained with the Oxford formulation of the
lattice Boltzmann method. This formulation has the advantage that one may independently
specify physical properties such as the interfacial tension and the viscosities of the phases.
Unlike alternative methods such as the boundary element method and the front-tracking method,
it is not necessary to track the interface or the contact line. Solid-liquid-liquid systems were used
in the analysis. We have found that drops migrate on a solid surface from the hydrophobic side to
the hydrophilic side. This appears to be consistent with published experimental studies.
Simulations also take into account the chemical roughness of the solid surface. It was found that
drops migrate more slowly on a rough surface, which is also consistent with experimental
studies.
3A-24
Surface Properties of Contact Lenses
M. J. STACHOWSKI, G. Friends, D. Seelye, J.Kunzler, S. Rastogi, Research Development and
Engineering, Bausch & Lomb Inc., Rochester, NY, Mark.Stachowski@Bausch.com
Hydrogel polymers can be used as biomaterials, and specifically in ocular applications where
specific bulk properties are needed for transparency and oxygen permeability. There is difficulty
in controlling these complex formulations as to what species move from the gel matrix toward
the surface so as to inhibit or enhance surface interactions, such as encountered with a contact
lens in a tear film. Specific surface properties are needed for such complex interactions within
aqueous pool of mucin, lipids and proteins. These needs depend highly on the patient’s and their
wear modality. Additionally in silicone hydrogel polymers, a surface must be rendered
hydrophilic, without compromising the surface properties necessary for such deposition
resistance. One method commonly used is plasma treatment, which can be used to form surfaces
from the bulks’ surface moieties or from new surfaces formed from new monomeric moieties.
This functions clinically to impart comfort, wettability, deposition resistance and/or a lubricous
nature. Selection of the plasma gas / monomer and the process conditions are specific to the
substrate being modified. Vastly different surface properties can be imparted which can change
the surface morphology, deposition uptake and surface chemistry, as detected by atomic force
microscopy (AFM), scanning electron microscopy (SEM), gas chromatography – mass
spectroscopy (GC/MS) and X-ray photoelectron spectroscopy (XPS). Characterization of the
surfaces’ elemental composition using XPS can show less pronounced differences, despite
significant changes in morphology and deposition uptake, but such subtle differences play a
significant role. Hence, surface properties can be controlled and / or enhanced through the
surface plasma chemistry controlled by the gas and process conditions, specific to a substrate
chemistry, in an attempt to impart these surface property modifications. A general overview
background of the technology and examples will be given.
3A-25
Verification of the Langmuir Isotherm for the Adsorption of Proteins to Polymer Surfaces
Jeong-Yeol Yoon, Marika Klappert, LONNIE J. LUCAS, Department of Agricultural and
Biosystems Engineering, The University of Arizona, Tucson, AZ, jyyoon@email.arizona.edu
The Langmuir isotherm has been the best fit for the adsorption of proteins to polymer surfaces,
which assumes 1:1 binding of an active site on both the protein and surface. This has long been
debated since proteins are large enough to make multivalent attachments to surfaces, where n:1
binding seems likely. To explain this discrepancy, we estimated the contact area (Ac) for a single
protein molecule anchored to the surface of a polymer by comparing the Gibbs free energy
change of adsorption (–ΔGads, kJ/mol) with the work of adsorption (Wads, mJ/m2). –ΔGads was
calculated as 20–28 kJ/mol, from the equilibrium constant (K) obtained from isotherm data of
albumin/hemoglobin adsorption on plain/carboxylated/sulfonated polystyrene submicron
particles. Wads was calculated as 20–70 mJ/m2, based on the surface tensions of water, proteins
and polymer particles obtained from contact angle data of five solvents on their thin films. Both
–ΔGads and Wads decreased as the surfaces became more hydrophilic. Dividing –ΔGads by Wads
provided Ac = 0.6–1.4 nm2/molecule, which is much smaller than the cross-sectional areas of
albumin/hemoglobin (28–40 nm2/molecule). This indicates that only a very small portion of the
protein surface is in direct contact with the polymer surface.
3A-26
Fibronectin / Polyelectrolyte Multilayer Assemblies: Film Formation and Cell Attachment
Studies
CORINNE R. WITTMER, Paul R. Van Tassel, Dept. of Chemical Engineering, Yale University,
New Haven, CT, corinne.wittmer@yale.edu
Electrostatically driven layer-by-layer (LbL) self-assembly is a simple and robust method for
realizing structurally tailored biomaterial coatings, of thickness ca. 10 nanometers, containing
biofunctional ligands. We investigate the placement of fibronectin – a matrix protein useful in
tissue engineering applications – onto multilayer films formed by the alternate deposition of
poly-L-lysine (PLL) and dextran sulfate (DXS). We use optical waveguide lightmode
spectroscopy (OWLS) and quartz crystal microbalance with dissipation (QCM-D) to characterize
film formation in situ. We find fibronectin adsorption to a film terminated with PLL to exhibit
rapid kinetics and a large saturation, and to be essentially irreversible. In contrast, fibronectin
adsorption to a film terminated with DXS is characterized by slower kinetics and a more modest
saturation, and is partially reversible. We find no evidence of fibronectin penetrating the
multilayer film. We use optical microscopy to determine the influence of
fibronectin/polyelectrolyte multilayer assemblies on human umbilical endothelial cell (HUVEC)
behavior. We observe the addition of fibronectin to DXS terminated assemblies to result in
drastically increased HUVEC spreading and circularity. In contrast, the addition of fibronectin
to PLL terminated assemblies leads to only subtle changes in the HUVEC response. We discuss
this key difference in terms of the structure of the adsorbed fibronectin layer as well as the
charge and hydration of the multilayer film.
3A-27
Surface Assembly of Protein in Correlation to Protein Crystallization
Y. W. Jia, X. Y. LIU, Department of Physics, National University of Singapore, Singapore.
phyliuxy@nus.edu.sg
The assembly of lysozyme (hen egg white) at the surface of aqueous solution follows the same
behaviors as amphiphilic molecules. The critical assembly concentration appearing in the protein
solutions is found to coincide with the equilibrium concentration of protein crystals under given
conditions. The crystallization of protein regarded as a typical case of protein self-assembly in
three dimensions has been discussed. The result reveals also the correlation between protein
crystallization and the two-dimensional self-assembly at the surface of substrates. It follows that
the protein crystallization conditions can be determined without protein crystals.
3A-28
Surface Treatment with Polymers for Biofouling Retardation
XIAONONG CHEN, Rovert Pelton, Department of Chemical Engineering, McMaster
University, 1280 Main Street West, Hamilton, ON, Canada, chenxi@mcmaster.ca,
peltonrh@mcmaster.ca
Polystyrene (PS), polyethylene (PE), polypropylene (PP), glass, and stainless steel were exposed
to aqueous solutions of a series amphiphilic polymers at room temperature, including poly(Nisopropylacrylamide) (PNIPAM), polypropylene oxide (PPO)-polyethylene oxide(PEO) block
copolymers and PEO. Dynamic contact angle measurements of the material surfaces before and
after the treatment indicated that: (1) almost no adsorption of PEO on PS, PE, and PP surfaces;
(2) PPO-PEO copolymers adsorbs only minimally on PE and PP surfaces; (3) PNIPAM adsorbs
on both hydrophobic and hydrophilic surfaces. The surface morphologies of the materials before
and after polymer adsorption were investigated by profilometry. Protein adsorption on PNIPAM
pre-adsorbed surfaces was investigated by dual polarisation interferometry (DPI) and
profilometry using lysozyme as the model protein. The results obtained indicate that PNIPAM
can significantly improve the bio-deposition resistance of artificial surfaces, making PNIPAM
treatment attractive for preventing biofouling of protein separation membranes and biomedical
devices.
3A-29
Atomic Force Microscopy Studies of Langmuir-Blodgett Films: Storage Protein from
Aleurone Cells of Barley and Lipid Associations
M. T MOAIA-COTISEL*, G. Tomoaia**, T. Yupsanis***, A.-I. Balea*, A. Mocanu*, *BabesBolyai, University of Cluj-Napoca, Physical Chemistry and Biophysics Department, **Iuliu
Hatieganu, University of Medicine, Department of Orthopaedic Surgery, 3400 Cluj-Napoca,
Romania, and ***Aristotle University of Thessaloniki, Biochemistry Department, Greece,
mcotisel@yahoo.com
The adsorption of storage globulin protein from aleurone cells of barley (Hordeum vulgare L.)
on lipid films (e.g. dipalmitoyl phosphatidyl choline: DPPC or stearic acid: SA) at the air/water
interface was studied by Langmuir-Blodgett technique (LBT) and tapping mode atomic force
microscopy (AFM). The behavior of protein is complex generating large colloidal particles
which appear to strongly adsorb on the lipid monolayers. The obtained results indicate a long
range order within protein, protein:DPPC and protein:SA layers, as well as electrostatic effects,
and lipid surface and protein attraction. The protein layer shows a unique structural pattern in its
adsorbed state that might laid down during grain development and it can generate complex
supramolecular structures involving various classes of biological molecules, e.g., lipids, natural
pigments or combination of those. Due to the high stability of protein layers, the storage protein
might fulfill the key requirement as building blocks for the production of novel supramolecular
materials as required in molecular nanobiotechnology and biomimetics.
3B-01
How Do Hydrated Ions Act as the Lubricant between Silica Surfaces in Solutions?; A
Nanotribology Study in Aqueous Solutions by AFM
B. C. Donose, E. Taran, I. U. Vakarelski and K. HIGASHITANI, Department of Chemical
Engineering, Kyoto University, Kyoto, Japan. k_higa@cheme.kyoto-u.ac.jp
Understanding of nanotribological phenomena has a critical importance for the fast development
of existing and emerging technologies, such as chemical mechanical planarization and
microelectromechanical systems. Using Lateral Force Microscopy, we have investigated the
frictional interaction between a micron-size silica particle and a silica wafer in solutions under
the conditions characteristic for these technologies. It was found the friction force was related
with two types of mechanisms: one of them was related to the microstructure of the layer of
surface adsorbed cations, the kind of cations and water molecules, and the other one to the
microscopic properties of the silica surfaces contacting water.
At high electrolyte concentrations, the hydrated cations adsorbed on the surfaces were found to
act as efficient boundary lubricants. The smaller in size and more hydrated cations were, the
more frictionless and lubricated two surfaces were. With respect to the pH of solutions, no
significant change in the frictional force was found between pH 3 and pH 8. But at pH > 9, the
friction force is extremely small in the region of low normal loading force, but it increases
exponentially in the region of high loading force. It is suggested that the microscopic property of
the silica surface was changed at high pH. The detailed mechanism will be discussed in the
presentation.
3B-02
Interaction between polymer, surfactant and colloid studied by a novel force measurement
technique
JOHN PHILIP, Department of Chemistry, University of Hull, Hull, United Kingdom,
j.philip@hull.ac.uk
Using a new force measurement approach,1 we investigate the role of associative polymers on
colloidal forces and its implications on long term stability of the emulsions. This experimental
tool has been very effective to obtain insight into the very early stages of polymer-surfactant
interaction. It has been found that the interaction between polymer, surfactant and colloid can
lead to three distinct scenarios, depending on the sequence of adsorption of polymer and
surfactant onto the colloidal interface. In the first two cases, where the colloidal interface is
adsorbed with or without surfactant molecules, polymer-surfactant complexation occurs in the
bulk phase but without being adsorbed at the interface. Under the above condition, the repulsive
force between colloidal droplets is not significantly altered by polymer-surfactant complexes. In
the third case, where the polymer is pre-adsorbed at the colloidal interface, polymer-surfactant
interaction leads to dramatic changes in repulsive forces (10-13-10-11N) and onset of repulsion
(upto 100nm) due to conformational changes of polymers at the interface, enhancing the stability
of the colloid considerably.
3B-03
Investigation of the Role of Geometry and Fluid Structure in the Description of Depletion
Forces via Scaled Particle Theory-based Integral Equations for Hard Sphere Fluids
D. W. SIDERIUS, D. S. Corti, School of Chemical Engineering, Purdue University, West
Lafayette, IN, dsideriu@purdue.edu, dscorti@purdue.edu
The ability of colloidal particles to self-organize suggests that colloids could generate complex
microstructures for use as templates for advanced materials. Precise control of colloidal
dispersions, however, rests on our understanding of the forces between colloids and between
colloids and surfaces. Depletion forces, which arise solely due to entropic considerations, are a
class of forces which play an important role in colloidal aggregation. Depletion forces are
typically modeled with excluded volume arguments, although these arguments usually fail to
fully capture all entropic effects. To gain further insight into the origin of depletion forces, we
examine the fluid structure of hard sphere colloids near surfaces via a newly derived integral
equation based on the scaled particle theory of confined hard sphere fluids. Exact solution of the
integral equation, along with simulation results, predicts the appearance of a local density
enhancement near the colloid-surface interface. These results suggest that the excluded volume
argument is not totally adequate for describing depletion forces and instead the geometry of and
the fluid structure near the colloid-surface interface must be considered. Overall, the integral
equation lends new insights into the nature of depletion forces and highlights the importance of
fluid structure in the understanding depletion interactions.
3B-04
Aggregation Modeling using Sinc Methods
TERRY A. RING, Dept. Chemical Engineering, University of Utah, Salt Lake City, UT,
T.Ring@m.cc.utah.edu
Aggregation and breakage processes are modeled the population balance equation, which
accounts for the particles in the system. The population balance is an integro-partial differential
equation that is coupled to the mass, heat and momentum balance equations that are simply
partial differential equations. The population balance can be written in various forms, e.g.
discrete or cumulative number as well as discrete or cumulative mass, with various bases, e.g.
particle size or particle volume, as the internal coordinate. The population balance in all of these
forms and bases is still an integro-partial differential equation. This paper solves the cumulative
mass population balance in Steigles integral form using Sinc collocation, a finite element
method, for several problems including deaggregation of fractal aggregates, aggregation of
polystyrene latex particles and the combination of aggregation and breakage of NaCl crystals.
3B-05
The Role of Ultrasonic Analysis in Colloid Characterization
TÕNIS OJA, Gabriel DosRamos, Robert W. Reed, Matec Applied Sciences Northborough, MA
Most colloid particle characterization has been typically carried out in severely diluted systems
employing primarily light-scattering methods. In recent years, ultrasonic analysis has been
steadily developed into a viable and attractive option. Ultrasonic analysis permits colloid
characterization at native concentrations, without the need for sample dilution. This presentation
provides a review, including recent developments, of the various applications of ultrasonic
attenuation, sound speed, acoustic impedance and electroacoustic measurements to colloid
characterization.
3B-06
Measurement of the Zeta Potential of Planar Solid Surfaces by Means of a Rotating Disk
J. D. HOGGARD, P. J. Sides, D. C. Prieve, Department of Chemical Engineering, Carnegie
Mellon University, Pittsburgh, PA, jhoggard@andrew.cmu.edu
A method of measuring the zeta potential of disks is described. Combing the hydrodynamic
properties of a rotating disk, the solution of Laplace’s equation for the potential, and the
electrokinetic boundary condition, an equation relating the zeta potential of the disk to the
streaming potential is obtained. Theory predicts the streaming potential is proportional to the
rotation rate raised to the 3/2 power. Placing an electrode near the disk surface and a reference
electrode at infinity is shown to be the ideal place to make the streaming potential measurement.
Experimental measurements of the streaming potential are made on silicon oxide disks in a dilute
potassium chloride solution. The experimental results are shown to agree very well with theory.
Determination of the zeta potential using streaming current measurements is also possible, but a
current collection efficiency must first be determined because not all the current from a disk
flows through the auxiliary electronic current path. Experimental results are shown to agree with
published data.
3B-07
Structuring of Nanoparticles and Micelles Confined between Surfaces
A. TULPAR, B. Fazelabdolabadi, P. Van Tassel, J. Y. Walz, Department of Chemical
Engineering, Yale University, New Haven, CT
The aim of this work is to investigate the structuring of charged spherical particles between two
surfaces as a function of bulk particle concentration. The structuring behavior of the particles can
be deduced from the force profiles between two surfaces. In this work, we measure the force
between a silica particle and a silica plate in aqueous solutions of particles by atomic force
microscopy. We use two types of spherical particles: nanoparticles and micelles. The
nanoparticles are Ludox silica, and the micelles are composed of sodium dodecylsulfate. In both
of the systems, the force profiles are oscillatory and the wavelength of these forces follows the
spacing between the particles in the bulk ((bulk number density)–1/3), not the effective size of the
particles. At high concentrations of nanoparticles (above 10% by volume) in low ionic strength
solutions, the wavelengths of the forces are smaller than the bulk spacing. Addition of salt to
these solutions brings the wavelengths back to the bulk spacing. We also perform Monte Carlo
simulations to compare with our experimental results and to better understand the structuring
behavior of the charged spherical particles confined between surfaces.
3B-08
Charge Instability Induced Breakups of Droplets Containing Ionic Solutes and Suspended
Nanoparticles
KUO-YEN LI and Asit K. Ray, Department of Chemical Engineering, University of Kentucky,
Lexington, K, kli2@uky.edu
We have examined the charge stability limits of single evaporating microdroplets containing
ionic solutes and nanoparticles. Droplets were suspended in an electrodynamic balance, and a
high precision light scattering technique based on optical resonances was used to determine the
size and the size change of a droplet at a charge instability induced breakup. The charge level
and the charge loss at a breakup were obtained from the dc voltages required to gravitationally
balance the droplet prior to and following the breakup. We have examined diethylene glycol
(DEG) and triethylene glycol (TEG) droplets containing lithium chloride (LiCl) as well as
suspended polystyrene nanoparticles at varying concentrations. While results on pure droplets of
DEG and TEG show that breakups due to the charge instability occur at the Rayleigh limit,
droplets containing LiCl solute explode at significantly higher charge levels than the Rayleigh
limit. Similar results were observed in droplets containing nanoparticles, that is, a droplet can
remain stable at a charge density level greater than three times the Rayleigh limit. The results
indicate that the charge stability limit depends on the concentration of solute or nanoparticles as
well as the size of nanoparticles in the droplet.
3B-09
The use of the QCM-D technique as a versatile transducer technology for Biosensor
applications
PATRIK BJÖÖRN**, Fredrik Höök*, Ralf Richter***, *Department of Solid State Physics,
LTH, Sweden, **Q-Sense Inc, 1200 Quail Street, Newport Beach, CA, *** Laboratoire
d’Imagerie Moléculaire et Nano-Bio-Technologie, IECB, Université Bordeaux I, 16 Avenue Pey
Berland, 33607 Pessac Cedex, France, patrik.bjoorn@q-sense.com
Recent years have seen various biosensor concepts taking the step from the lab into industrial
applications. The advance of the quartz crystal microbalance with dissipation (QCM-D)
monitoring offers increased information content and flexible routes in the surface chemistry
design. In addition, the QCM-D technique is based on an electro-mechanical principle, thus
offering label-free and real-time measurements on surface reactions occulting on any solid
surface (metal, metal oxide, polymer) in highly viscous and non-transparent liquids. As a
consequence, the QCM-D technique offers unique information for designing novel surface
chemistries for a large variety of applications, ranging from corrosion studies, via unspecific
adsorption of polymers and biomolecules, to specific biorecognition studies. By measuring not
only changes in frequency, related to adsorbed mass, simultaneous recording the crystal damping
(energy dissipation), theoretical models can be used to deduce structural changes within thin
adsorbed layers.
Recent progress nicely illustrates the use of the QCM-D technique as a biosensor platform
compatible with diverse surface chemistry architectures, including lipid bilayers,[1] thiol and
silane based functionalized self assembled monolayers,[2] functionalized PLL-PEGs,[3] PEICMC hydrogels[4] etc. In particular, these surface architectures have been used to immobilize
specific detector molecules (i.e antibodies, [4] DNA, [1] coagulation factors, [5] lipid vesicles
[1],). In this presentation, the wide-ranging possibilities offered by the QCM-D principle will be
reviewed, with particular focus on different means to immobilize probe molecules for specific
bio recognition reactions.
3B-10
Quartz Crystal Microbalance Based on Impedance Analysis – Modeling of Interfacial
Layer Properties
TAPANI VIITALA1, Jorma Vuorinen1, Piotr Kujawa2, Francoise Winnik2, 1KSV Instruments
Ltd, Höyläämötie 7, 00380 Helsinki, Finland, 2Université de Montréal, Faculté de Pharmacie,
Pavillon Roger-Gaudry 2900, boul. Édouard-Montpetit, Montréal, QC, Canada,
tviitala@ksvltd.fi.
The quartz crystal microbalance (QCM) technique with its many variants is rather mature
technique nowadays and it is routinely used to provide information about a range of interfacial
processes either in gas or liquid environments. It is widely known that in case of rigid films the
QCM works very well as an accurate gravimetric instrument. However, the situation changes
dramatically when the QCM is used in certain liquid environments or for studies of thick and soft
interfacial layers such as polymers. In such cases the overlayer is often not rigidly coupled to the
quartz crystal surface and the response of the QCM also depends on the visco-elastic properties
of the overlayer.
We present here how the QCM based on impedance analysis can be utilized to give information
on the deviations from rigidity of surface-bound films, and how the measured data can be used
for modeling the visco-elastic properties and thickness of the overlayers. We have chosen as
model systems one Newtonian liquid, one thick polymer layer in air and a layer-by-layer buildup process of polyelectrolytes in liquid. The modeling used is based on a lumped element
approximation of the Transmission Line Model.
3B-11
Multi-Layer Adsorption of Sodium Alginate on Quartz Surfaces: A QCM-D Study of
Adsorbed Layer Properties
ALEXIS J. DE KERCHOVE, Menachem Elimelech, Department of Chemical Engineering,
Environmental Engineering Program, Yale University, P.O. Box 208286, New Haven, CT,
alexis.dekerchove@yale.edu
Understanding the adsorption of alginates onto solid surfaces is of paramount importance in a
wide range of industrial and natural processes. A quartz crystal microbalance with dissipation
(QCM-D) is used to study the multi-layer adsorption of alginate as a function of the
polysaccharide concentration and ionic strength. Monitoring the rate of energy dissipation with
the QCM-D provides insights into the viscoelastic properties of the adsorbed layer of the alginate
polyelectrolyte along with the associated ions and water molecules. We show that for alginate
concentrations of 0.1 and 1 g/L, the frequency, or adsorbed mass, increases with increasing ionic
strength. The variation of the dissipation with the frequency suggests a linear relationship
between the mass shift and the dissipation of the adsorbed layer. The normalization of the
dissipation by the frequency change due to alginate adsorption demonstrates that the viscoelastic
properties of the layer vary as a function of the ionic strength and alginate concentration. The
results are discussed in terms of the variations in molecular configuration and compressibility of
the adsorbed layer as a consequence of shielding of the polyelectrolyte charges with increasing
ionic strength.
3B-12
Surface Interactions of PGMA-DETA Polymeric Adsorbent in Copper Ion Removal
CHANGKUN LIU, Renbi Bai*, Department of Chemical and Biomolecular Engineering,
National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore,
chebairb@nus.edu.sg
Adsorption has gained increasing importance in environmental engineering as a purification
method to remove various pollutants, such as heavy metal ions. Surface interactions play a
crucial role in the effectiveness of the process. In this study, novel polymeric adsorbent was
developed from PGMA (poly-glycidyl methacrylate) and were surface-functionalized with
diethylenetriamine (DETA). The resultant PGMA-DETA adsorbent was examined for the
removal of copper ions from aqueous solutions. Infrared Microspectroscopy (IR-Microscope)
was used to study the surface functional groups and chemical changes with copper ion
adsorption. X-ray Photoelectron Spectroscopy (XPS) was utilized to reveal the various surface
interactions in the adsorption. It was found that the adsorbent was very effective in copper ion
adsorption in pH 4 and 5. In addition to the electrostatic interaction, the IR and XPS results show
that surface complexation of the nitrogen and possibly the oxygen atoms with copper ions played
an important role in the adsorption of copper ions from aqueous solutions.
3B-13
Effects of an Electric Field on Surface Tension of Conducting Liquids
A. Bateni†, S. Laughton†, A. AMIRFAZLI‡, A.W. Neumann†, †Department of Mechanical and
Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON, Canada,
‡Department of Mechanical Engineering, University of Alberta, 4-9 Mechanical Engineering
Building, Edmonton, AB, Canada
Understanding the influence of an electric field on interfacial properties of liquids is of
importance from both fundamental and practical standpoints. Charged or electrified liquids
currently play a key role in various applications, ranging from microfluidic devices to
agricultural treatments. Nevertheless, the effects of the electric field on liquid surface properties
are not well-understood, mainly due to the lack of reliable tools and methodologies to measure
such effects. A novel methodology, called Axisymmetric Drop Shape Analysis for Electric
Fields (ADSA-EF), is developed to measure the effect of the electric field on the surface tension
of conducting drops. ADSA-EF matches numerically generated drop profiles with the shape of
electrified drops observed in an experiment, taking the surface tension as an adjustable
parameter. The best match between numerical and experimental profiles corresponds to the true
value of surface tension in the electric field. ADSA-EF detected an increase of the order of one
percent in the surface tension of conducting liquids, as well as a second-order correlation
between liquid surface tension and the applied electric potential. Details of the methodology
along with the experimental results will be presented at the conference.
3B-14
Enhancement of Adhesion to Heterogeneously Patterned Substrates
DANIEL A. RAMRUS and John C. Berg, Department of Chemical Engineering, University of
Washington, Seattle, WA
Organofunctional silanes have long been used as promoters of adhesion between polymers and
mineral oxide surfaces. The present work reports adhesion results obtained using binary
combinations of adhesion-promoting and non-adhesion promoting silanes patterned onto an
oxide adherend surface. The effects of pattern shape, texture (feature size) and the fractional
coverage of the adhesion-promoter are explored for the bonding of poly(vinyl butyral) (PVB) to
-aminopropyl triethoxysilane (APS), an
adhesion promoter, and octadecyl trichlorosilane (ODTS), a non-adhesion promoter for this
system. Climbing drum peel tests reveal that adhesion depends on feature size, shape and area
ratio of the silanes, in many cases resulting in a reduction of adhesion compared with that for a
pure APS film, but in other cases producing enhancements of as much as 80%. Among the
conditions examined thus far, the greatest adhesion was achieved using square islands, 12 x 12
mm in size, surrounded by 1.5-mm wide borders of non-adhesive. Adhesion enhancement is
attributed to arrest and confinement of crack propagation. As the crack propagates through a
heterogeneous surface it will blunt at the end of an adhesive patch, and must re-nucleate at the
start of the next adhesive domain.
3B-15
Two Hundred Years of Contact Angle Research (1805-2005)
ALIDAD AMIRFAZLI, Department of Mechanical Engineering, University of Alberta,
Edmonton, AB, Canada, a.amirfazli@ualberta.ca
This paper provides an overview of contact angle research in the past 200 years starting with the
pioneering work of Thomas Young at 1805. It discusses the current thinking in contact angle
research and points to the future areas of interest from a technological as well as fundamental
point of view. The presentation mainly will center around solid-liquid-fluid systems, but it will
also touch on liquid-liquid-fluid systems. Various interpretations of contact angles in terms of
solid surface energetics, line tension, and adhesion among other issues will be discussed. Topics
of current interest such as superhydrophobicity (ultrahydrophobicity) and contact angle
hysteresis will be discussed from theoretical as well as experimental perspectives. Finally, merits
of various techniques used in measuring or determining contact angles from ordinary solid
surfaces to micro- and nano-spheres will be discussed briefly.
3B-16
Determination of Surface Tension of Fluoropolymers from Contact Angles and the Role of
Liquid and Polymer Molecular Properties
H. TAVANA, A. W. Neumann, Department of Mechanical and Industrial Engineering,
University of Toronto, 5 King’s College Road, Toronto, ON, Canada, tavana@mie.utoronto.ca,
neumann@mie.utoronto.ca
Contact angle data for liquids with bulky, inert molecules on smooth, inert polymer surfaces fall
on a smooth curve when plotted as a function of liquid surface tension. If one or more of these
conditions is not met, deviations of typically ~1-3 degrees occur. The existence of such
deviations introduces an element of uncertainty in the determination of accurate surface tension
of solids. This problem is addressed through contact angle measurements with a large number of
liquids of different molecular properties on four different fluoropolymers, i.e. Teflon AF 1600,
poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate),oly(octadecene-alt-N-(n-(Rf)butyl)maleimide),
and poly(ethene-alt-N-(n-(Rf)butyl)maleimide). It is shown that the deviations are not an artifact
of experimental procedures such as film preparation techniques but have physical causes. Several
mechanisms are identified as the possible cause for the deviations: vapor adsorption onto the
polymer film, an alignment of liquid molecules in the vicinity of the solid surface, and
reorientation of the polymer chains upon contact with the test liquids. It is shown that shape,
size, chemical composition, and the molecular configuration of liquid molecules as well as of the
polymer chains all play a role. In the light of the results obtained, requirements for the
determination of accurate surface tension of fluoropolymer films especially with respect to the
probe liquids will be presented.
3B-17
A Methodology for Surface Tension Measurement from the Analysis of Liquid Bridges
Shapes
M. G. CABEZAS, J.M. Montanero, Dpto. Electrónica e Ingeniería Electromecánica, Universidad
of Extremadura, 06071 Badajoz, Spain, mguadama@unex.es
Surface tension is widely measured using ADSA techniques. These techniques are versatile and
accurate in many situations. However, ADSA measurements present a lack of accuracy for small
values of the capillary constant, that is, when working with two liquids of similar densities or
when gravity is low. In these situations, the drop shape is not sufficiently sensitive to variations
of the surface tension, and ADSA can not measure this quantity accurately. In this work the
sensitivity of drops and liquid bridges to surface tension has been studied numerically. Results
show that liquid bridges are more sensitive with less volume, so they can provide more accurate
surface tension measurements when ADSA fails. The main goal of this contribution is to propose
a methodology that uses liquid bridges instead of drops to measure the surface tension value. The
principle of this methodology is the same as that of ADSA: the surface tension is measured by
comparing the theoretical prediction of the liquid bridge shape to the experimental one. This new
methodology has been validated by comparing the results with those given by ADSA in
situations when ADSA is reliable.
3B-18
Do Polysaccharides Such as Dextran and Their Monomers Really Increase the Surface
Tension of Water?
M. HOORFAR, M. Kurz, Z. Policova, M. Hair, A. W. Neumann, Department of Mechanical and
Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON, Canada,
hoorfar@mie.utoronto.ca
It has been reported in the literature that polysaccharides and their monomers increase the
surface tension of water. The effect was interpreted as a depletion of the solute molecules from
the water-air interface. This paper presents accurate measurements of surface tension of different
concentrations of dextrose solution as well as its polymer (i.e. dextran). An automated drop
shape technique called Axisymmetric Drop Shape Analysis (ADSA) was used for the surface
tension determination. The accuracy of the results was evaluated using a shape parameter, Ps ,
which has been used to quantify the range of the applicability of ADSA. The results of the above
study show that dextrose solutions decrease the surface tension of water in contradiction to the
results in the literature. Surface tension decreases continuously with increasing concentration. A
similar effect was observed for the dextran solutions.
It is well known that electrolyte solutions, e.g. sodium chloride, increase the surface tension of
water. To verify that the setup and the methodology are capable of measuring increases in
surface tension, a similar experiment was conducted with a sodium chloride solution. The results
obtained from ADSA show that the sodium chloride increases the surface tension of water. It is
concluded that dextrose and dextran decrease the surface tension of water. Thus, there is no
evidence of depletion.
3B-19
The Interfacial Tension of Spherical and Aspherical Colloidal Dispersions
DUANE JOHNSON, Lichun Dong, Department of Chemical & Biological Engineering, The
University of Alabama, Tuscaloosa, AL, djohnson@coe.eng.ua.edu
The adsorption energy of spherical and aspherical particles onto a liquid-fluid interface and the
effect of the line tension are investigated. The results show that without line tension, aspherical
particles always prefer to lie flat in the plane of the interface. However, line tension plays a
significant role in determining the adsorption of an aspherical particle. First, the line tension
creates an energy barrier for the adsorption of particles onto an interface. The planar
configuration has a larger energy barrier due to the longer contact line. Therefore, the particles
prefer to enter the interface in a homeotropic configuration and then rearrange to a planar
configuration or an oblique configuration with a small tilt angle. Second, for prolate particles, an
energy maximum occurs at some tilt angles when the line tension is large. Therefore, once the
prolate particle is adsorbed on the interface in a homeotropic configuration or with a larger tilt
angle, it must conquer an energy barrier to rearrange to a planar configuration. For cylindrical
particles, when the line tension is higher, the planar configuration will not be the most energy
favorable configuration. The cylindrical particles prefer to stay in the interface with a small tilt
angle.
3B-20
Measurement of Line Tension in Liquid-Liquid Systems
Z. TAVASSOLI, A. Bateni, A. W. Neumann, Department of Mechanical and Industrial
Engineering, University of Toronto, Toronto, ON ,Canada, satav@mie.utoronto.ca
A new methodology is presented for line tension measurement in liquid-liquid systems.
Line tension may be an important parameter for the interpretation of the contact angles of small
drops and may play a key role in various technologies such as oil-water emulsion in rocks,
stability of foams, micro-fluidic circuits, and microbial systems. Although line tension is a welldefined thermodynamic quantity, controversy regarding both the order of magnitude and the sign
of this quantity persists.
The methodology is based on a novel procedure of contact angle determination for a lens of one
liquid floating on the other liquid. Line tension is highly sensitive to the measured value of this
contact angle. Hence a sophisticated technique (Polynomial Fitting for Line Tension) was
developed for high accuracy measurement of contact angles. The proposed system is free from
contact angle hyteresis and hence of more immediate thermodynamic relevance than similar
work with solid/liquid systems.
The design is able to provide relatively stable and reproducible line tension measurements.
Preliminary results using a lens of dodecane at an air-water interface suggests an order of
magnitude of 10-6 J/m with a negative sign for the line tension. Details and implications will be
discussed.
3B-21
Critical Evaluation of the Surface Complexation Model for Metal Oxide Aqueous Interface
based on Measurements of Surface Potential
NIKOLA KALLAY, Tajana Preocanin, Ana Cop, Laboratory of Physical Chemistry, Faculty of
Science, University of Zagreb, Marulicev trg 19, 10000 Zagreb, Croatia. nkallay@chem.pmf.hr
Ionic equilibria at metal oxide aqueous interface is commonly interpreted on the basis of the
Surface Complexation Model that takes into account mechanism of specific interfacial reactions,
their equilibrium constants, and the structure of electrical interfacial layer. Several variations of
the basic model were used for interpretation of experimental data. The common experimental
techniques are acid base titrations of suspension providing surface charge density in the inner
plane, counter ion adsorption measurements and electrokinetics. It was found that these
experimental data may be successfully interpreted by several different variations of the model so
that one needs to introduce a new experimental technique that might help in solving the problem.
There were several attempts to measure surface potential at the inner plane by metal electrodes
covered by layer of a metal oxide. However, due to the porosity of oxide layer the data were not
reliable. Recently, we have constructed an electrode made of monocrystaline hematite enabling
the reliable measurements. These data, together with other data obtained by classical methods,
enables evaluation of all parameters characterizing the interface and critical test of the
assumptions involved in the application of the Surface Complexation Model.
3B-22
Investigating the Aqueous Surface Chemistry of TiO2 Pigments using ATR-IR
Spectroscopy
SCOTT DICKIE, Jim McQuillan, Department of Chemistry, University of Otago, Dunedin, New
Zealand. sdickie@alkali.otago.ac.nz
TiO2 is the most widely used white pigment in the paint and ceramic industries due to its opacity
and light scattering, which impart high levels of whiteness and brightness. However the end
performance of paint films in categories such as opacity, gloss and colour distribution is directly
related to the stability achieved in the pigment dispersion. The stability of the pigment dispersion
can be improved by the addition of surfactants, which to date have been chosen based largely on
information obtained from empirical methods and without any fundamental knowledge of the
surface chemistry involved.
Typical TiO2 pigments are made up of a particle of rutile between 200 and 300 nm in diameter
which is then coated with silica followed by alumina. Pseudoboehmite has been used as a model
for the surface of TiO2 pigments and its aqueous surface chemistry has been investigated using
attenuated total reflection infrared (ATR-IR) spectroscopy. The identification of a ligand system
that will provide more permanent attachment of a surfactant to the pigment surface has been
targeted. The talk will outline the aqueous surface chemistry of pseudoboehmite and TiO2
pigments.
3B-23
Effects of Charge and Size on Condensation of Supersaturated Water/n-Butanol Vapor on
Nanoparticles of SiO2, TiO2, d-Mannose, and Rhamonose
CHIN-CHENG CHEN, Yu-An Shen, Hsiu-Chin Cheng, Chia-Te Lin, Department of Chemical
Engineering, National Cheng Kung University, Tainan, Taiwan, 701, ROC,
ccchen@mail.ncku.edu.tw
The effects of size and charge on the condensation of a supersaturated water/n-butanol vapor on
monodisperse nanoparticles of SiO2, TiO2, D-Mannose and Rhamonose were investigated in a
flow cloud chamber (FCC). The dependence of the critical supersaturation, Scr, on particle size
of a diameter 5 to 30 nm as well as on charge and charge polarity are determined experimentally.
A novel electrospray aerosol generator was developed to generate a high concentration of
nanoparticles of less than 10 nm by electrospraying precursors or solution followed by the
thermally decomposition or drying. For neutral particles, the experimental Scr decreases with
increasing particle size at a rate in a reasonable agreement with the predictions of the Fletcher’s
version of Volmer’s theory of heterogeneous nucleation. For charged particles, the nucleation
occurs at a Scr lower than that on neutral particles and the charge effect fades away as particle
size increases. In addition, a sign preference is detected, e.g., water vapor condenses more
readily on negative charge particle, a trend consistent with those observed on ions. However,
both effects of charge and charge polarity on Scr are stronger than that predicted by Volmer’s
theory for ion-induced nucleation.
3B-24
Preparation temperature dependence of size and polydispersity of thiol-coated gold
nanoparticles determined by SAXS
KURT ERLACHER1, Jørgen M. Jørgensen2, Jan S. Pedersen2, Kurt V. Gothelf2, 1Bruker-AXS
Inc., 5465 East Cheryl Parkway, Madison, WI, 2University of Aarhus, Department of Chemistry,
Langelandsgade 140, DK-8000 Aarhus C, Denmark, kurt.erlacher@bruker-axs.com
For the present study monolayer protected gold colloids were synthesized by the Schiffrin
procedure, with fixed amounts of the reactants but at various temperatures. The main purpose
was to investigate the relation between the preparation temperature and the size of the colloids
and their corresponding size distribution. To eliminate possible influences on the mixing
procedure of the reductant different series of synthesis were prepared. The water solvated
reductant was either added slowly over 30 seconds or added at once to obtain fast reaction. It was
expected that the colloids become bigger at elevated preparation temperatures. In order to extend
the temperature range in which the colloids can be synthesized, three different methods of
synthesizing the colloids in the absence of water were carried out. The first of these methods was
to directly add the reductant in its pure form to the reaction mixture, at the second attempt
another solvent for the reductant was found and the third one was to try to transfer the reductant
to the organic phase with a phase transfer catalyst. The presence and the sizes of the colloids can
be ideally analyzed using the method of small-angle x-ray scattering (SAXS). A laboratory
SAXS system (NanoSTAR SSS) consisting of Goebel Mirrors, three pinhole collimation and a 2
Dimensional single photon detector (Bruker AXS Inc.) was used for these experiments. A clear
trend towards bigger colloid sizes at elevated temperatures was obtained.
3B-25
Size control of nanoparticles during precipitation the BNG way
I.H. LEUBNER, Crystallization Consulting, 35 Hillcrest
ileubner@crystallizationcon.com, www.crystallizationcon.com
Drive,
Penfield,
NY,
Size control of nanoparticles I achieved by controlling nucleation during precipitation and crystal
growth after nucleation. The number of crystals formed and the amount of crystalline mass
formed determine the crystal size. The balanced nucleation and growth (BNG) model
quantitatively correlates crystal nucleation to addition rate, time of reactant addition, solubility,
temperature, and presence of growth restrainers. Experimental results of precision
crystallizations will be presented for size control of nano-particles.
3B-26
Synthesis of Platinum Multipods: Control of Anisotropic Growth
XIAOWEI TENG, Hong Yang+*, +Department of Chemical Engineering and Laboratory for
*Laser Energetics, University of Rochester, Rochester, NY
Synthesis of nanostructure with well-controlled morphology has been drawn a great attention
recently for its application for tailoring the electronic, optical, magnetic and catalytic properties
of advanced materials. Here we report a highly effective synthesis of platinum multipods from
platinum 2,4- pentanedionate in organic solvents by Polyol process. A trace amount of silver
acetylacetonate is used to trigger the nucleation and the anisotropic growth of Pt nanocrystals. Pt
nanoparticles in forms of I- and V-shaped bipods, various types of tripods, and planar and threedimensional (3D) tetrapods have been successfully synthesized by controlling the reaction
temperature, precursor concentration and by using Ag(acac). Transition from multipods to
spheres of Pt particles is observed and discussed. High resolution transmission electron
microscopy (HRTEM), X-ray diffraction (XRD), nanoelectron diffraction and energy dispersed
X-ray (EDX) are used to characterize the structures of Pt multipod nanocrystals. A model of
formation based on the induced kinetically controlled growth will be discussed.
3B-27
Transport in polymer gels with charged spherical inclusions
REGHAN J. HILL, Department of Chemical Engineering, McGill University, Montreal, QC
Canada, reghan.hill@mcgill.ca
Transport of ions in fluid-saturated polymer gels (e.g., polyacrylamide) with immobile charged
inclusions (e.g., silica or latex micro-spheres) is examined under conditions where perturbations
to a uniform equilibrium state are driven by (weak) macroscopic gradients of electrostatic
potential, pressure or electrolyte concentration.
Electro-migrative, diffusive and convective contributions to the ion fluxes are provided for a
wide range of electrolyte concentrations, (inclusion) zeta potentials and (polymer)
hydrodynamic permeabilities. The theory, which is not limited by the diffuse double-layer
thickness or zeta potential, provides a first step toward a quantitative interpretation of
experiments. With the application of an electric field, for example, the particle contribution to
the bulk electrical conductivity is obtained. Also of interest, for its influence on micro-mixing
and enhanced transport, is the strength of the electric-field-induced flow.
3B-28
Study of Surface Tension of Lung Surfactant: Influence of Humidity on the Properties of
the Surface Film
R. GITIAFROZ1,2, E. Acosta2, Z. Policova1, H. Tavana1, A. W. Neumann1, 1Department of
Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto,
ON, Canada, 2Department of Chemical Engineering and Applied Chemistry, 200 College St.,
Toronto, ON, Canada, roya@mie.utoronto.ca
The surface tension of a lung surfactant, i.e. BLES (Bovine Lipid Extract Surfactant), is
investigated using a constrained sessile drop methodology. Preliminary work revealed some
irregularities, e.g. certain instabilities of the surface film upon compression. It is shown that
moisture plays an important role. At low concentrations of BLES solution (0.5 mg/ml) and in the
presence of humidity, the surface films are unstable regardless of the extent of compression, i.e.
5%, 10%, 20%, or 30%. This means that when the film is kept compressed at a surface tension
lower than the equilibrium value of ~24 (mJ/m2), it cannot sustain the pressure and the surface
tension increases towards equilibrium. However, the film is more stable in a dry atmosphere.
Apparently, in dry conditions, dehydration of the surface film increases the liquid-crystalline
phase transition temperature of phospholipids that are present in the interface. On the other hand
in a humid environment, the film is fully hydrated. Hydration of the film decreases the transition
temperature of phospholipids and makes them more fluid. Details and implications will be
discussed.
3B-29
Binary Colloidal Alloys at Liquid Interfaces – from Super Lattices to Stoichiometric
Clusters
T. S. HOROZOV, R. Aveyard, B. P. Binks, J. H. Clint, Surfactant & Colloid Group, Department
of Chemistry, University of Hull, Hull,United Kingdom, t.s.horozov@hull.ac.uk
The behaviour of monodisperse silica particles at oil/water interfaces has been studied by
microscope observations. Particles of different sizes and/or hydrophobicity and their mixtures
have been spread at the liquid interface to give one- or two-component particle monolayers.
Strong long range repulsion through the oil between very hydrophobic particles in onecomponent monolayers has been observed. The particles in these monolayers have been well
ordered in triangular lattices at very large interparticle distances (up to ~20 particle diameters). In
contrast, a weak repulsion between hydrophilic particles has been found. The repulsion is
mediated mainly through the water and one-component hydrophilic particle monolayers were
disordered and aggregated.
Binary mixtures of large (L) and small (S) very hydrophobic particles have formed twodimensional super lattices of LS2 or LS5/LS6 type depending on the composition. An interesting
selective attraction between very hydrophobic and hydrophilic particles with the same or
different sizes has been observed in their mixed monolayers. This resulted in formation of mixed
clusters containing one hydrophobic and several hydrophilic particles whose stoichiometry
depends on the composition of the mixture. The possible reasons for the selective attraction
between very hydrophobic and hydrophilic particles observed at the oil/water interface are
discussed.
3B-30
Characterization of Dry Adhesion Between Carboxymethyl Cellulose and Glassine Paper
ZHINAN FENG, Robert Pelton, Department of Chemical Engineering, McMaster University,
1280 Main Street West, Hamilton, ON, Canada. fengz@mcmaster.ca
A T-peel technique was developed in this study for characterizing dry adhesion between polymer
and paper. Several carboxymethyl celluloses (CMC) samples and glassine paper were examined.
It was found that this delamination technique was simple, fast, reliable, repeatable, and costeffective. The modes of interfacial failure and paper failure were observed depending on CMC
characteristics and dosage. T-peel force was not affected by the change in peel rate within the
range studied. However, the glassine paper showed significant two-sidedness in adhesion to
CMC. The results clearly indicated that the adhesion increased with molecular weight of CMC
but decreased with degree of substitution of CMC.
3B-31
A molecular dynamics study of the role of conventional and silicon surfactants in the
wetting of hydrophobic substrates by aqueous solutions
JONATHAN D. HALVERSON1, J. Koplik2, A. Couzis1, C. M. Maldarelli1, 1Department of
Chemical Engineering, 2Department of Physics, The Benjamin Levich Institute for Physicochemical Hydrodynamics, City College of the City University of New York, New York, NY
Many industrial processes rely on conventional surfactants to increase the wetting of
hydrophobic substrates by aqueous solutions. For instance, organic surfactants are added to
herbicide solutions in order to achieve a larger wetted area when the solution is applied to the
leaf of a plant, which due to the Epicuticular wax is a difficult-to-wet surface. For over three
decades it has been known that trisiloxane alkoxylate surfactants or superspreaders are far more
effective than conventional surfactants. However, superspreaders are photosensitive, toxic, and
relatively expensive. Classical molecular dynamics simulations are being conducted to determine
the mechanism by which organic and silicon surfactants increase the spreading of aqueous
droplets on hydrophobic surfaces. Sessile water drops containing either low-molecular-weight
alcohols or polyoxyethylene surfactant molecules have been simulated at 298 K on an atomistic
graphite lattice. During the course of the simulation surfactant molecules tend to the three-phase
contact line where the headgroups are found to interact strongly with water and the tailgroups are
directed radially outward and displaced from the droplet. An implementation of the fast
multipole algorithm is used for the rapid evaluation of long-range electrostatic forces.
Complementary sessile drop wetting experiments are being conducted by our research group.
3B-32
Bovine Serum Albumin (BSA) as an adhesive for wet cellulose
SHUNXING SU, Robert Pelton, Department of Chemical Engineering, McMaster University,
Hamilton, ON, Canada, peltonrh@mcmaster.ca
Bovine Serum Albumin (BSA) was investigated as an adhesive for wet cellulose by 90º peeling
of regenerated cellulose membranes laminated with BSA as the adhesive. Drying and curing at
elevated temperature (120ºC) was required for strong adhesion. Ionic strength of the re-wetting
water almost had no effect on wet adhesion. Oxidization of the cellulose membranes to introduce
more carboxyl groups onto their surfaces increased the wet peel strength by 60%. Implying the
peel failures happened at the protein/cellulose interface. The re-wetting pH of the laminated
specimens prepared with oxidized membranes determined the ultimate peel strength while the
initial pH of the BSA solution had little effect. The pH dependent wet strength might be good for
the pulp recycling.
3B-33
Motion of liquid drops on a horizontal surface with a wettability gradient
NADJOUA MOUMEN, R. Shankar Subramanian, John B. McLaughlin, Center for Advanced
Materials Processing and Department of Chemical Engineering, Clarkson University, Potsdam,
NY, moumenn@clarkson.edu
Results from experiments performed on the motion of drops of tetraethylene glycol in a
wettability gradient present on a silicon surface are reported and compared with predictions from
a theoretical model. The gradient in wettability was formed by exposing strips cut from a silicon
wafer to the vapors from an alkylchlorosilane. Video images of the drops captured during the
experiments were subsequently analyzed for drop size and velocity as functions of time and
position along the gradient. In separate experiments on the same strips, the static contact angle
formed by small drops was measured and used to obtain the local wettability gradient to which a
drop is subjected. The Reynolds, capillary, and Bond numbers in the experiments were relatively
small. Even though the velocity of a given drop varied with position on the gradient surface, it is
shown that a quasi-steady theoretical model that accounts approximately for the hydrodynamic
resistance and the local driving force adequately describes the observed behavior of the velocity
of the drops. Also, it is shown that the instantaneous velocity at a given location in the gradient
scales linearly with the planform radius of the drop, as predicted by theory.
3B-34
Adhesion between Precipitated Calcium Carbonate and Cellulose Fibre
Y. XU, R. Pelton, McMaster center for Pulp and Paper Research, Department of Chemical
Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, Canada,
xuy2@mcmaster.ca
The adhesion between Precipitated Calcium Carbonate (PCC) particles and Softwood Bleached
Kraft (SBK) Pulp fibres was investigated with a 90 degree peel test of two-ply laminated
handsheets. A sparse layer of PCC particles was laid at ply/ply interface and the delamination
force was found exponentially reduced with the PCC content as a result of stronger fibre-fibre
bonds readily replaced by weak PCC-fibre bonds. The strength of 1.7m scalenohedral PCCfibre laminates was approximately 1.4N/m compared to 20N/m for filler-free laminates.
Surface coated with carboxylmethyl cellulose (CMC) of PCC particles can significantly improve
PCC-fibre laminates strength (2.7N/m). However, polyvinylamine (PVAm) can only promote
fibre-fibre laminates strength (38N/m) but has no notable effect on PCC-fibre laminates strength.
Phosphate containing copolymers with polyacrylamide (PAMVP) and polyvinyl alcohol (PVAP)
can also strengthen PCC-fibre bonds with the fact that PVAP is more effective than PAMVP.
4-01
Expanding the Utility and Understanding of Room Temperature Ionic Liquids: Including
Micelle Formation and Interactions with Gold Nano-particles
DANIEL W. ARMSTRONG, Department of Chemistry, Iowa State University, Ames, IA,
sec4dwa@iastate.edu
Room temperature ionic liquids (RTILs) cannot be adequately characterized on the basis of
polarity or any single parameter scale. RTILs are complex entities compared to the relatively
simple molecular solvents used in most chemical processes.[1] They are capable of a wider range
of intermolecular interactions than most other solvents. This includes: dispersive, n-, -,
dipolar, hydrogen bonding, hydrophobic, and ionic interactions. A multi-parameter scale, that
takes into account the many different possible solvent properties, can be used to properly
characterize RTILs as well as other solvents.[1] Their unique properties appear to induce the
formation of solvophobic normal micelles when surfactants are dissolved in RTILs.[2] Also, gold
nano-particles are more easily formed and dispersed in RTILs than in normal solvents.[3] We can
now understand why RTILs behave differently than single solvents for organic reactions, and
which ones are most promising as MALDI matrixes,[4] for extractions and as chromatographic
stationary phases.[5,6] Chiral ionic liquids and their use will be discussed as well.[7]
4-02
Development of a Universal Method for the Determination of Enantiomeric Compositions
of Pharmaceutical Products
CHIEU D. TRAN, Victor I. Grishko, Daniel Oliveira, Department of Chemistry, Marquette
University, P. O. Box 1881, Milwaukee, WI, chieu.tran@marquette.edu
A new method has been developed for the determination of enantiomeric compositions of a
variety of drugs including propranolol, atenolol, and ibuprofen. The method is based on the use
of the near-infrared (NIR) technique to measure diastereomeric interactions between an added
carbohydrate compound with both enantiomeric forms of an analyte followed by partial least
square analysis of the data. The fact that the method works well with all three macrocyclic
carbohydrates with different cavity size (i.e., -, - and - cyclodextrin) as well as with sucrose,
which is a linear carbohydrate, clearly demonstrates that it is not necessary to have inclusion
complex formation in order to produce effective diastereomeric interactions. Rather a simple
adsorption of the analyte onto a carbohydrate is sufficient. Since inclusion complex formation is
not a requisite, this method is not limited to the amino acids studies here but is rather universal
and sensitive as it can, in principle, be used to determine enantiomeric compositions for all types
of compounds with only microgram concentration and enantiomeric excess as low as 1.5 %, in
water or in a mixture of water and organic solvent. Furthermore, it does not rely on the use of
rather expensive carbohydrates such as cyclodextrins but is equally as effective even with a
simple and inexpensive carbohydrate such as sucrose.
4-03
Determination of Environmentally Important Metal Ions by Fluorescence Quenching in
Micellar Solutions
F. Nome, H. D. FIEDLER, E. Sapelli, G. C. Bedendo, R. S. Mello, L. V. Vargas, Departamento
de Quimica, Universidade Federal de Santa Catarina, Caixa Postal 476, Florianopolis, SC,
88049-970, Brazil, fiedler@qmc.ufsc.br
This work describes the determination of environmentally important metal ions by fluorescence
spectroscopy in micellar solutions. Several metal ions have been used as quenchers of the
fluorescence of naphthalene, in aqueous micellar sodium dodecyl sulfate (SDS). The quenching
by the metal ions can be described by the Stern-Volmer equation and the detection limits are
improved with low SDS concentrations. Apparent Stern-Volmer constants decrease in the order:
Fe3+ > Cu 2+ > Cr3+ > Ni2+ > Pb2+ and reflect the sensitivity of the method. Similarly, using the
cationic chelating agent 8-hydroxyquinoline (8-HQ), allows the simple, rapid and sensitive assay
of Zn2+ in aqueous micellar solutions of cetyl trimethyl ammonium bromide (CTABr). In the
absence of CTABr, the complex formed between 8-HQ and Zn2+ is insoluble. Micelle-enhanced
fluorescence spectroscopy and fluorescence quenching can be used as analytical methods of
general application and is an interesting area of research to improve the detection limit of several
analytical methods.
4-04
Solid-Phase Microextraction: a Link between Micellar Extraction and Gas
Chromatography
VERÓNICA PINO, Francisco J. Conde, Juan H. Ayala, Ana M. Afonso, Venerando González.
Department of Analytical Chemistry, Nutrition and Food Sciences, University of La Laguna, E38205, Spain, veropino@ull.es
The Micellar Solid-Phase Microextraction (MSPME) is a new technique for sample treatment.
MSPME intends to combine the advantages of the micellar extraction with the advantages of the
gas-chromatography by means of the solid-phase microextraction (SPME). The present work
shows not only the use of MSPME to quantify solutes in solid matrixes but also its ability to
determine partition coefficients of solutes between micellar media and aqueous phases.
In the first case, the PAHs contained in a reference marine sediment have been extracted with
surfactants. Afterwards, these compounds are removed from the micellar media by using the
adequate SPME fiber, and determined by GC-MS. This step is accomplished just desorbing the
SPME fiber in the injector of the GC, without needing to remove the surfactant prior to injection.
With this new method, the previous treatments in the analysis of any non-polar compound
contained in solid samples could be reduced to a stage of solubilization of the same ones in a
micellar medium followed by a separation using SPME-GC.
In the second case, the partition coefficients of 16 PAHs and 29 Phenols between ionic and nonionic micellar media and aqueous phases have been established using MSPME. The obtained
results show that this technique is especially adequate by its simplicity and by leaving the
binding equilibrium undisturbed.
4-05
Development of Functionalized Admicelles in Separation Science
T. SAITOH, M. Hiraide, Graduate School of Engineering, Department of Molecular Design and
Engineering, Nagoya University, Chikusa, Nagoya, Aichi, Japan, saitoh@numse.nagoya-u.ac.jp
Surfactant molecules cooperatively sorb on solid surfaces and form aggregates namely hemimicelles or admicelles in the aqueous solution. Through mixing of surfactants, porous solid
materials, and hydrophobic chelating agents or surfactant-conjugated substrates (affinity ligand)
in the aqueous solution led to the formation of media for the collection of metal ions or proteins.
Different from conventional separation media having chemically bound ligand, the
functionalized admicelles have degree of freedom in the preparation. Furthermore, dynamic
property and high water permeability of the admicelles can facilitate the interaction of ligand
with an objective compound. An admicelle composing of Triton X-100, porous polystyrenedivinylbenzene (Amberlite XAD-4), and Triton X-100-conjugated Cibabron blue 3GA (affinity
ligand) was found to be useful for purifying lysozyme from egg white, but was ineffective for the
collection of alcohol dehydrogenase (ADH). The uses of octadecylsilyl-silica gel instead of
XAD-4 and an affinity ligand having a longer polyoxyethylene moiety were effective for the
separation of ADH from bakers’ yeast.
4-06
Powerful Preconcentration Method for Ultra Trace Amounts of Polycyclic Aromatic
Hydrocarbons and its Application to the Environmental Analysis
Shukuro Igarashi1, YOSHITAKA TAKAGAI2, 1Department of Biomolecular Functional
Engineering, Faculty of Engineering, Ibaraki University, Nakanarusawa 4-12-1, Hitachi, Ibaraki,
Japan, 2Laboratory of Physical and Chemical Science, Cluster of Science and Technology,
Fukushima University, Kanayagawa 1, Fukushima, Japan, igarashi@hcs.ibraki.ac.jp,
takagai@sss.fukushima-u.ac.jp
A preconcentration procedure is one of the most important techniques for the environmental
analysis. In this study, lower ppt levels of polycyclic aromatic hydrocarbons (PAHs) in
environmental water can be determined by the proposed powerful preconcentration method with
high performance liquid chromatography using fluorescence detection (FL/HPLC). The
preconcentration method consists of the combination of the blue cotton method (solid-phase
extraction) and the homogeneous liquid-liquid extraction. In the case of the homogeneous
liquid-liquid extraction, PAHs in the eluate of solid-phase extraction were extracted into micro
volume of sedimented phase. The proposed method could completely concentrate 1 liter to 20
microliter within one hour and the 20 microliter of sedimented phase is directly injected into
FL/HPLC. The entire preconcentration factor was 50,000-fold. Six kinds of PAHs were
determined in the range of 3.0 × 10-18 ~ 4.5 × 10-11 mol L-1. These chemicals were also
satisfactorily separated. By changing the combination of various preconcentration methods or
instrumental analysis, the various samples could be analyzed.
4-07
Cloud Point Extraction as a Preconcentration Step for the Analysis of Metals in
Environmental and Biological Samples
M. F. Silva, R. A. Olsina, L. FERNÁNDEZ, Área de Química Analítica, Departamento de
Química, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, 5700
– San Luis, Argentina, lfernand@unsl.edu.ar
Cloud point extraction (CPE) is a powerful separation method with a pronounced capability to
preconcentrate trace and ultra-trace metals in diluted samples of diverse origin such as
environmental, biological and industrial concern. This procedure have advantages over those
currently available including low cost, safety, feasibility for injection of the surfactant-rich phase
into any hydrodynamic analytical system and high capacity to concentrate a wide variety of
analytes of widely varying nature with high recoveries and very high concentration factors. CPE
has been employed for the preconcentration of metal complexes such as mercury, aluminium and
rare-earth elements prior to inductively coupled plasma atomic optical emission spectrometry
(ICP-OES) and Absorciometry UV-Vis coupled to flow injection (FI). On the other hand, the
possibility to preconcentrate lead and aluminium without added chelating agents has been
demonstrated. Indeed, the coupling of CPE to Capillary Electrophoresis (CE) was successfully
performed to preconcentrate and simultaneously determine lead, platinum/palladium, and
iron/dysprosium. The samples under analysis include different water samples, human saliva,
urine and industrial samples.
4-08
Enhanced Organic Photovoltaic Performance from Nanoparticle – Polymer Blends
Marisol Reyes-Reyes1, Kyung Kim1, DAVID L. CARROLL1, Seamus Curran2, 1The Center for
Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University,
Winston-Salem NC, 2Department of Physics, New Mexico State University, Las Crucis NM,
carroldl@wfu.edu
Blends of single walled carbon nanotubes (SWNTs), semiconducting nanostructures, nanometals (Ag, Au), and/or fullerene derivatives with conjugated polymers (MEH-PPV, PFO,
PEDOT, P3OT, P3HT), have been of great interest recently as a mechanism to raise the overall
performance efficiency of organically-based, flexible, devices such as photovoltaics, organic
light emitting diodes, and more. We have recently developed novel methods for controlling both
the electronic properties of the nano-phase and the long range “meso-structure” of the blend.
Through the use of selective doping (boron and nitrogen dopants) in carbon nano-structures we
have demonstrated control over the donor-acceptor role of the nano-phase in the host, allowing
for tailoring of the specific trapping levels introduced. Thus, as we show with time-of-flight, we
are able to introduce donor or acceptor states within the HOMO-LUMO gap of the host, and
control the relative positions of these states. Secondly, we have demonstrated that an order can
be created within the nano-phase, with controlled placement and orientation of the nanoparticles. These ordered nano-blends of conjugated systems exhibit a number of exciting
properties including: modified carrier mobilities, optical absorption, and exciton separation
dynamics. In this work we integrate this meta-functional nano-phase blend into a standard
flexible organic photovoltaic device. Using commodity polymers, surprisingly high efficiencies
can be obtained.
4-09
Morphological Control and Spectrometric Applications of Gold Nanorods
S. YAMADA, Department of Applied Chemistry, Graduate School of Engineering, Kyushu
University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Japan, sunaotcm@mbox.nc.kyushu-u.ac.jp
Gold nanorods (NRs), rod-like nanoparticles, show characteristic two plasmon bands based on a
longitudinal oscillation mode along the long axis (far-red/near-infrared region) and a transverse
mode perpendicular to the long axis (visible region). Thus, the NR shows a distinct dichroic
property. Quite recently, we developed a novel and simple method for the preparation of gold
NRs, by the combination of chemical reduction and subsequent photoirradiation. We have first
succeeded in well-dispersed fixing of the gold NRs onto a glass substrate by the layer-by-layer
approach. When the NR-modified plate was immersed into the solvent, the longitudinal plasmon
band showed substantial red shift, while the transverse SP band showed no substantial shift. The
degree of peak shift was roughly correlated with the order of refractive index (dielectric
constant) of the solvent. The monoparticle layer film of gold NRs was also prepared at the
liquid-liquid interface. The NR film showed distinctly larger Raman scattering signals than the
corresponding nanospheres film. We also prepared the aggregate of phosphatidylcholinemodified NRs and DNA. Controlled release of DNA from the aggregates was possible by pulsed
irradiation of near-infrared laser light.
4-10
Luminescent Nanoparticles as Labels for Biological Molecules
THOMAS NANN, Freiburg Materials Research Center (FMF), University of Freiburg, StefanMeier-Strasse 21, D-79104 Freiburg, Germany, thomas.nann@fmf.uni-freiburg.de
Luminescent nanoparticles such as semiconductor nanocrystals (so called Quantum Dots [QDs])
or rare earth doped nanoparticles gained increasing interest over the past several years.
Compared with organic fluorophores, such particles possess substantial optical advantages: For
example they don’t bleach under excitation, possess a narrow – often tuneable – spectral
linewidth and make new detection techniques possible e.g. upconversion luminescence or
lifetime multiplexing.
The application of these particles in bioanalytics is promising, but a pre-requisite is, that they are
colloidally stable in biological buffers and can be coupled to appropriate biomolecules. Since
high-quality (monodisperse) nanoparticles are usually synthesised in non-polar media as for
example trioctylphosphinoxide (TOPO) or high-boiling alkanes, the particle surface must be
derivatised in such a way that on the one hand the phase-transfer is possible and on the other
hand biomolecules such as proteins or nucleotides can be coupled selectively.
First an overview of luminescent nanoparticles, which are used in bioanalytic applications, is
given. Preparation methods regarding those applications are discussed. Furthermore, different
possibilities for non-polar/polar phase-transfers are presented. Thereby the encapsulation of
single nanoparticles with silica layers will be a special emphasis (cf. figure 1). Moreover,
possibilities for the coupling of nanoparticles to biomolecules are discussed. Finally, some
examples for the imaging of biological systems with luminescent nanoparticles are presented.
4-11
Nanostructure-Assisted Laser Desorption Ionization Mass Spectrometry in Bioanalysis
Nancy H. Finkel, Zhong Guo, Amel Ganawi, LIN HE, Department of Chemistry, North Carolina
State University, Raleigh, NC, Lin_He@ncsu.edu
Surface-assisted laser desorption ionization mass spectrometry (SALDI-MS) has drawn
considerable attention for its efficiency in detection of species in the low-mass region.
Nevertheless, the correlation of the surface property of roughened inorganic substrate with its
desorption ionization efficiency remains unclear. We report herein a new nanofabrication
method to generate well-controlled surface features and systematically vary the surface geometry
with the aim of seeking a fundamental understanding of the SALDI mechanism. Specifically,
convective self-assembly is used to generate close-packed 2-D nanoparticle arrays on a flat Si
surface. This hexagonal-packed nanoparticle array is then used as a mask in nanosphere
lithography to selectively remove portions of Si surfaces in reactive ion etching (RIE) and
generates triangle-shaped nanocavities in periodic patterns with pre-defined feature parameters.
Mass spectrometry detection of small molecules and peptides on such substrates shows good
sensitivity with little fragmentation and minimal background interference. Ordered feature size,
shape, and surface density are tailored by varying fabrication conditions. The impacts of surface
geometries on MS performance are correlated. The thermal properties of the substrates are
investigated. The use of the substrates in metabolite profiling and quantitation of Arabidopsis
thaliana extracts is also presented.
4-12
Gold Nanoparticle Matrices for Bioanalysis using Matrix-Assisted Laser Desorption
Ionization
KATHERINE A. STUMPO, John A. McLean, David H. Russell, Laboratory for Biological Mass
Spectrometry, Department of Chemistry, Texas A&M University, College Station, TX,
kstumpo@mail.chem.tamu.edu
Nanoparticles, esp. gold nanoparticles (AuNPs), have found wide application in chemical
biology and biochemical applications. Importantly, the optical and electronic properties of NPs
depend on size, shape, composition, and derivatization. Thus, NPs can be tailored to specific
applications, e.g. using functionalized AuNPs for selective isolation of target analytes. We
present here the utility of AuNPs and surface derivatized AuNPs as potential matrices for matrixassisted laser desorption ionization (MALDI) mass spectrometry (MS). These alternative
substrates offer a number of advantages over conventional MALDI matrices (e.g. small organic
acids): (i) greater flexibility in sample deposition conditions (e.g. pH, solvents, etc.), (ii)
relatively uncomplicated spectra in the matrix region (low mass range), (iii) Au-cluster species as
internal standards for mass calibration, and (iv) AuNPs afford a very high shot-to-shot and spotto-spot reproducibility (<10 % RSD). Furthermore, the surface chemistry of AuNPs also plays an
important role in the ionization process, and has been investigated. Surface association of ions
and the solvent structure around these species in solution have an effect on analyte interactions
with the AuNPs, thus leading to changes in ionization efficiency. These studies present many
interesting avenues that can be pursed in various chemical biology systems.
4-13
Chemical Separations Using Nanoparticles
LUIS A. COLON, Jason A. Anspach, Hector Colón, Glorimar Vicente, Melissa N. Dunkle,
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo,
NY, lacolon@buffalo.edu
The use of chromatographic columns packed with small particle diameters allows the exploration
of the theoretical limits in liquid chromatography, as theory predicts that a reduction in particle
diameter would provide an increase in separation efficiency with a concomitant reduction in
analysis time. Our research group has been exploring such predictions by first synthesizing
organosilica particles with diameters in the nanometer range and using them for capillary
electrochromatography (CEC) and ultrahigh pressure liquid chromatography (UHPLC).
Although a gain is noticeable when using particle diameters below 1 µm, the actual gain
combined with practical considerations are factors to consider in the separation formats studied.
Using another nanoparticle technology and the nanoscale separation technique of capillary
electrophoresis, we also explore the use of fluorescent nanoparticles as “labeling” tags to
enhance detection of biomolecules. We will discuss our recent findings as we implement these
new technologies in chemical analysis.
4-14
Gold Nanoparticles in Open-Tubular Capillary Electrochromatography and Supercritical
Fluid Extraction
JEREMY D. GLENNON, Elizabeth Guihen, Li Yang, Norma M. Scully, Anne M. O'Keeffe,
Niamh M. J. Curran, Jean-Marie Prat, Gerard P. O'Sullivan, Department of Chemistry,
Analytical & Biological Research Facility (ABCRF), and Supercritical Fluid Center, University
College Cork, Cork, Ireland, j.glennon@ucc.ie
Nanoparticles exhibit unique size-dependent optical, catalytic, magnetic, and electronic
properties compared to their bulk counterparts and can enhance a variety of technologies
including chemical processing, medical, electronic, environmental, separation and sensing
applications. Gold nanoparticles in particular, are among the most stable metal nanoparticles,
and are viewed as key materials and building blocks, with emerging applications in biology,
catalysis and nanotechnology.
To-date, very little research has been devoted to the application of nanoparticles in separation
science. The significant advances, which have been made in electrophoresis and microchip
separations, show the promise to enhance separation performance by using nanoparticles. For
example, latex nanoparticles have been used to coat a micromachined channel on-chip, and onchip ion chromatography of inorganic anions, nitrate, nitrite, and iodide, has been achieved.
In this paper, important new roles for gold nanoparticles in open-tubular electrochromatography
(OTCEC), and in the extraction of this precious metal using supercritical carbon dioxide will be
highlighted. Specifically, the use of alkylthiolgold nanoparticles in OTCEC to improve the
efficiency of separation and the selectivity between selected solutes will be demonstrated, in
particular, for hydrophobic test solutes and for selected polycyclic aromatic hydrocarbons
(PAHs).
4-15
Development, Evaluation and Application of Nanoparticles as Stationary Phases for
Gas Chromatography
ROBERT E. SYNOVEC,a Gwen M. Gross,a Jay W. Grate,b (a) Center for Process Analytical
Chemistry, Department of Chemistry, Box 351700, University of Washington, Seattle, WA
98195.
(b)
Pacific
Northwest
National
Laboratory,
Richland,
WA,
synovec@chem.washington.edu
We are exploring using a thin film of gold-centered monolayer protected nanoparticles (MPNs)
as a stationary phase for open-tubular gas chromatography (GC). The MPN films have
thermodynamic and mass transfer properties that serve them well, providing good chemical
selectivity and high separation efficiencies (high N). High surface area-to-volume ratios of
MPNs provide ample sample loading capacity. A majority of our work has been with
dodecanethiol MPNs, with a dodecanethiol monolayer linked to a gold nanoparticle. Films of
dodecanthiol MPNs ranging from 10 to 60 nm provided efficient separations with various
capillary dimensions. The MPNs have a nominal diameter of about 3 nm, so film depths are
only a few nanoparticle diameters. High-speed separations with dodecanethiol MPNs in a film
depth of ~ 15 nm in a square channeled capillary have been achieved and these results hold
considerable promise for the development of “high performance” microfabricated GC. We are
also investigating MPN columns for ultra high-speed GC, where separations of several analytes
in a fraction of a second are achieved, engendering the notion that GC can function like a
chemical sensor. Current development of polar stationary phases utilizing 4-chlorobenzenethiol
MPNs and 4-(trifluoromethyl)benzenethiol MPNs will also be discussed.
4-16
Non-Cross-Linking Aggregation of DNA-Carrying Nanoparticles for Single-Base
Substitution Assay
MIZUO MAEDA, Kazuo Hosokawa, Kae Sato, Bioengineering Laboratory, RIKEN, 2-1,
Hirosawa, Wako, Japan, mizuo@riken.go.jp
The graft copolymer consisting of poly(N-isopropylacrylamide) (PNIPAAm) and single-stranded
DNA was prepared as a DNA-conjugated material. Interestingly, the DNA-conjugate was found
to form nanoparticles above physiological temperature (Langmuir, 20, 313-319 (2004)). We
found that non-cross linking aggregation of the nanoparticles was induced by the hybridization
of the surface-bound DNA with the full-match complementary DNA, but not with one-base
mismatch. The results demonstrated that the non-cross linking aggregation of DNA-carrying
nanoparticles is useful for analyzing various SNPs. The core material is not restricted to
PNIPAAm; DNA-functionalized gold nanoparticle (15 nm diameter) was found to show a
similar aggregation phenomenon induced only by the fully-complementary DNA, resulting in
rapid color change within 3 min at ambient temperature (J. Am. Chem. Soc., 125, 8102-8103
(2003)). This methodology is general in principle and applicable for wide variety of clinical
diagnosis.
4-17
Enzymatic Amplification of Chemical Signals Inspired by Biological Signal Transduction
J. KIKUCHI, Y. Sasaki, Graduate School of Materials Science, Nara Institute of Science and
Technology, Ikoma, Nara, Japan, jkikuchi@ms.naist.jp
Intermolecular communication between a receptor and an effector on the biomembrane surface
plays a pivotal role of the information processing in biological system. We have recently
developed an artificial intermolecular communication system on colloidal lipid vesicles, as a
molecular device, inspired by the biological signal transduction. The system is constituted in
combinations of an artificial ditopic receptor, an enzyme as an effector, and a bilayer-forming
synthetic lipid. The cationic bilayer membrane formed with the synthetic peptide lipids or the
Cerasome-forming lipids was an effective platform for self-assembling of such functional
molecules. On the membrane surface, the enzymatic activity was effectively synchronized with
ditopic recognition of the receptor toward an external signal and a mediator species between the
receptor and the effector. Marked signal selectivity which is characteristic to the aqueous
colloidal interface was observed. The signal transduction efficiency was sensitively tuned with
gel to liquid-crystalline phase transition of the matrix membrane. The present molecular device
acts as a unique sensing system, in which the information on the molecular recognition of
various biologically important species by the receptor is transmitted to the enzyme and amplified
chemically as the catalytic reaction.
4-18
Gold Nanoparticles in Bioanalytical Assays
T. K. T. Nguyen1, ZEEV ROSENZWEIG2, 1School of Biological Science and Department of
Chemistry, University of Liverpool, Liverpool, United Kingdom, 2Department of Chemistry,
University of New Orleans, New Orleans, LA, zrosenzw@uno.edu
The presentation will focus on the synthesis, functionalization and application of gold
nanoparticles in biological assays and as pH sensors in biological samples. Gold nanoparticles
were synthesized at different sizes and characterized for their structural characteristics by
electronic microscopy and by UV-VIS spectrometry for their optical properties. High quality
particles were highly dispersed in aqueous solution, exhibited narrow size distribution and
showed a characteristic plasmon resonance absorption peak at around 520 nm. Once aggregated
the absorption signal broadened considerably and the color of the solution changed from red to
purple. This color change was used to monitor the aggregation of antibody coated gold
nanoparticles in their presence of their corresponding antigens. A compact laser-based detection
system was constructed and used to monitor the aggregation of the particles using a diode laser at
620 nm and signal and reference photodiodes to monitor the absorption of the analyte solutions.
The study concluded that aggregation-based assays of antibody coated gold nanoparticles could
be used to quantitatively determine the presence of antigens or antibodies in biological fluids.
4-19
Analytical Measurements Using Polymeric Surfactants
ISIAH MANUEL WARNER, Department of Chemistry, Louisiana State University, Baton
Rouge, LA, iwarner@lsu.edu
Over the past several years, we have employed polymeric surfactants as analytical reagents,
particularly as mobile phase additives for separations in capillary electrophoresis. We have
shown that our polymeric surfactants are broadly applicable to the separation of a variety of
analytes, including the separation of chiral compounds by use of chiral polymeric surfactants.
More recently, applications for the development of novel nanomaterials in the presence of
polymeric surfactants have been explored. Our studies have shown that these polymers are more
suitable than conventional micelles for both separations and spectroscopic applications. In this
talk, I will focus on the use of polymeric surfactants as separation reagents and for the
development of spectroscopic probes. The advantages of these reagents in comparison to regular
micelles will also be discussed, particularly with regard to the wide variety of applications. A
comparison of the use of polymeric surfactants for separations and spectroscopy will also be
made directly to separations and spectroscopy by use of conventional (unpolymerized) micelles.
4-20
Liposome Enhanced Firefly Bioluminescent Assay of ATP in the Presence of Surfactants
HIROFUMI TANI, Tamio Kamidate, Division of Biotechnology and Macromolecular
Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, JAPAN.
tani@eng.hokudai.ac.jp
The firefly bioluminescence (BL) assay has been widely used for the determination of ATP in
living cells. In this assay, the ATP extractants such as surfactants are required for the release of
ATP from cells, but they often inhibit the BL enzyme, luciferase. On the other hand, surfactants
are known to incorporate into liposomes composed of vesicular lipid bilayers. In addition,
cationic liposomes were found to enhance the BL intensity. Thus, a cationic surfactant being
used as an extractant, liposomes can eliminate the inhibitory extractant and can transform into
the BL-enhancer, cationic liposomes, by incorporating cationic surfactants. In this study, we
exploited such a double advantage of liposomes for the BL assay of ATP in the presence of
cationic surfactants. Liposomes consist of phosphatidylcholine and cholesterol were prepared by
the extrusion method using a polycarbonate filter. Benzalkonium chloride (BAC) was used as an
ATP extractant. The detection limit for ATP in the mixtures containing 0.06% BAC was 25pM
in the absence of liposomes. On the other hand, the BL intensity was remarkably increased by
the addition of liposomes into the assay mixture, resulting in the enhancement of the sensitivity
for ATP. The detection limit was improved to be 400fM.
4-21
Structure and Dynamics of Cationic and Nonionic Micelles: Neutron Scattering Studies
L. J. Magid1, W.-R. CHEN1, P. D. Butler2, D. Bossev3, 1Department of Chemistry, University of
Tennessee, Knoxville, TN, 2NIST Center for Neutron Research, National Institute of Standards
and Technology, Gaithersburg, MD, 3Physics Dept., Indiana University, Bloomington, IN,
lmagid@nsf.gov, wrchen@ion.chem.utk.edu
Micellar morphology in aqueous micellar solutions of cationic surfactants such as CTAX and
CPyX can be manipulated by changing the counterion. Organic counterions that penetrate the
micellar interface, such as salicylate and tosylate, produce very large, semi-flexible wormlike
micelles. Flexibility depends on the surfactant’s head group, the counterion, and the
concentration of added salts. Increasing concentrations of NaSal or NaTos cause the micelles to
undergo size reversion back to globules; the salt concentration at which this occurs is counteriondependent. SANS data that allow micellar contour lengths, persistence lengths and crosssectional radii to be determined will be presented, and size reversion will be found to correlate
with the unfavorable energetics of decreasing radii. Our fitting protocol incorporates changes to
the widely-used Pedersen-Schurtenberger scattering functions.
Neutron spin-echo studies on the local dynamics of linear and branched wormlike cationic and
nonionic micelles will also be presented, as well as of saturated micellar networks.
4-22
Studies of Reversible Guanosine Gels
LINDA B. MCGOWN1, Victoria A. Dowling2, Lawrence W. Dick2, 1Department of Chemistry
and Chemical Biology, Rensselaer Polytechnic Institute, 118 Cogswell, Troy, NY, 2Department
of Chemistry, Duke University, Gross Chemical Laboratory, Durham, NC, mcgowl@rpi.edu
Guanosine gels (G-gels) are self-assembled networks of hydrogen-bonded guanine tetrads
formed by guanosine nucleosides and nucleotides. G-gels combine desirable properties, such as
reversibility, tunability, aqueous solubility, and biocompatibility, with the unique ability to noncovalently and reversibly introduce functionality directly into the G-tetrad network of the gel via
hydrogen bonding. Their degree of organization and viscosity are dependent upon monomer
concentration, temperature, pH and cation content, providing a variety of parameters that can be
used to control their formation/disassembly and to reversibly modulate their properties. This talk
will present results of experiments in which G-gels are used for chiral separations in capillary gel
chromatography and molecular probe studies of these gel phases related to their performance in
chiral separations. Results will also be presented for gels that are under investigation for
bioencapsulation.
4-23
Hydrogen Bonded Molecular Macrocluster Formation at the Solid - Liquid Interface
KAZUE KURIHARA, Institute of Multidisciplinary Research for Advanced Materials, Tohoku
University, Katahira, Aoba-ku, Sendai, Japan, kurihara@tagen.tohoku.ac.jp
Liquid molecules at the solid-liquid interfaces often exhibit different properties from those in the
bulk, which is attributed to the surface-induced structuring of liquids. Elucidation of these
properties is important in nanoscience and nanotechnology. We recently have found that liquid
molecules with the hydrogen bonding functionalities (alcohol, carboxylic acid, and amide) form
a hydrogen bonded organized structure, which we call “molecular macrocluster”, on the silica
(glass and oxidized silicon) surface when they are adsorbed from their mixtures with non-polar
solvents. The surface silanol groups are essential for this structure formation. FTIR-ATR
spectroscopy demonstrates the hydrogen bonding interactions between the surface silanol groups
and adsorbed molecules in addition to those between adsorbed molecules. Surface forces
measurement reveals the long ranged attraction (e.g. extending to 30 ~ 40 nm for normal
monohydric alcohol in cyclohexane) due to the contact of the opposed adsorption layers. Half
the attraction range is close to the adsorbed layer thickness, which is extraordinarily long range.
Interesting differences are observed in the mode of adsorption depending on the chemical
groups. Dynamic properties of adsorbed molecules, ethanol on glass in cyclohexane, are studied
by NMR spectroscopy. We utilize this molecular macrocluster for preparing polymer thin-films
on solid surface.
4-24
Distribution of tert-Butylhydroquinone in Food-Like Emulsions Stabilized by C12E6
K. GUNASEELAN, Laurence S. Romsted, Rutgers, The State University of New Jersey,
Department of Chemistry and Chemical Biology, Wright-Rieman Laboratories, New Brunswick,
NJ, guna@rutchem.rutgers.edu
We have developed a new approach for estimating the distributions of antioxidants in opaque,
surfactant based, macroemulsions based on the pseudophase model for homogenous
microemulsions. The distribution of t-butylhydroquinone, TBHQ, in emulsions composed of
tributyrin, C12E6, and acidic water is described by two partition constants between the oil and
interfacial, POI, and the water and interfacial, PWI, regions. To estimate values for POI and PWI
requires fitting two independent data sets with two independent mathematical relations and
solving two equations simultaneously. One data set was obtained by electrochemical
determination of the observed rate constant, kobs, for reaction of TBHQ with an arenediazonium
ion probe as a function of C12E6 volume fraction. The second data set was obtained by
determining the partition constant, POW, of TBHQ between tributyrin and water in the absence of
surfactant by UV-Visible spectrometry, POW = 0.015. The values of the partition constants in the
emulsion are: POI = 11 and PWI = 7.11 x 102. Application of this approach to a variety of
antioxidants in emulsions containing different food oils and emulsifiers should provide new
insight into the factors controlling antioxidant distributions and may lead to a development of a
new scale of antioxidant efficiency.
4-25
Partitioning of Polar Aromatic Compounds to Organogels and Application for their
Extractive Removal from Organic Solvents
Melissa M. Stouffer, Julianne M. Braun, Dai Fang, WILLIE L. HINZE, Department of
Chemistry, Wake Forest University, PO Box 7486, Winston-Salem, NC, hinze@wfu.edu
Organogels are formed by the addition of gelatin to Aerosol OT [bis(2-ethylhexyl) sodium
sulfosuccinate] reverse micelle solutions at elevated temperatures followed by cooling. The
“solid” organogels have been shown to retain many of the general properties exhibited by
traditional reverse micelle solutions. Some of the general features and characteristics of these
materials will be described. Results regarding the stability of organogels in a variety of organic
solvents and aqueous mixtures will be presented. Partitioning data for the interaction of polar
aromatic compounds (such as substituted anilines, phenols, naphthols) with the AOT organogels
will be presented and compared to the partitioning observed for the same interaction with
solution AOT inverted micelles. The use of organogels to remove (extract) and/or concentrate
organic solutes from organic solvents will be discussed and the relevant extraction parameters
summarized. In addition, the use of such an approach as a preconcentration technique prior to
spectroscopic chemiluminescent determinations will be illustrated. Preliminary data obtained
using CTAB [hexadecyltrimethylammonium bromide] based organogels will also be presented.
4-26
Analytical Applications of Metal Nanoparticles
O. A. SADIK, M. Omole, D. Andreescu, A. Wanekaya, State University of New York at
Binghamton, Chemistry Department, Binghamton, NY, osadik@binghamton.edu
Palladium nanoparticles are of particular interest as catalyst for the synthesis of specialty
chemicals, nuclear waste and environmental applications. The objective of this work was to
develop a reliable experimental procedure for the synthesis and analytical applications of Pdbased nanoparticle. In designing advanced materials for nanosensors and environmental
remediation, nanomaterial synthesis procedures are increasingly required to control the shape
and size. Consequently, we have synthesized palladium nanoparticles through the reduction of
Pd (II) acetate using polyamic acid (PAA) as a reducing agent in an organic medium at room
temperature. The approach is based on subsequent capping and stabilization of the resulting
palladium nanoparticles by the PAA. The Pd-based nanostructured materials were characterized
using UV/Vis spectroscopy, scanning electron microscopy and transmission electron microscopy
(TEM). TEM image analysis showed the synthesized PAA-metal hybrid as well dispersed
particle of different shapes (Spherical, pyramidal and octahedral). The particle sizes were in the
range of 8.3-13.0 nm. In this presentation, we will show that palladium nanoparticles of variable
shape may be synthesized using a simple one step procedure involving the reduction of a
palladium salt by polyamic acid at room temperature. The possibility of fabricating a PAA-metal
hybrid material for environmental remediation and biosensing would be presented.
4-27
Colloidal CdSe Quantum Dots as Novel Luminescent Probes for Selective and Sensitive
Analytical Determination of Trace Amounts of Ions in Water Samples
J. M. COSTA-FERNANDEZ, M. T. Fernández-Argüelles, W. J. Jin, R. Pereiro, A. Sanz-Medel,
Department of Physical and Analytical Chemistry, University of Oviedo, 33006 Oviedo, Spain,
jcostafe@uniovi.es
Recent developments are stressing the importance of adequate surface chemistry in the
development of highly luminescent, water-soluble and biocompatible quantum dots (QDs) for
applications in bioanalysis and diagnostics [1, 2]. Moreover, analytical chemists have also started
to explore these nanomaterials for the development of a new generation of luminescence optical
probes.
Luminescence of QDs is very sensitive to their surface states; therefore, it is reasonable to expect
that eventual chemical or physical interactions between a target chemical species with the
surface of the nanoparticles would result in changes on their surface charge affecting the
efficiency of the core electron-hole recombination.
Following this approach, water-soluble surface-modified CdSe QDs have been synthesized and
evaluated as optical probes for selective and sensitive determination of trace amounts of small
ions (free cyanide and copper (II)) in aqueous solutions based on fluorescence quenching
measurements.
After QDs synthesis, a photostimulation was necessary in order to obtain a stabilized emission
profile resulting in reliable responses to the presence of the analytes. Moreover, the addition of
surfactant agents to the measured aqueous solution was found to greatly stabilize the colloidal
QDs and the fluorescent signals, resulting in a very high sensitivity for analyte detection
(detection limits in the low ng ml-1 range are obtained) [3].
4-28
Synthesis of Semiconductor Nanoparticles as Probe to Detect Supersaturated Dissolved
Oxygen
YONGXIA ZHANG, Duane T. Johnson, Chemical & Biological Engineering Department,
University of Alabama, Tuscaloosa, AL, djohnson@coe.eng.ua.edu
High-quality ZnS nanocrystrals are synthesized with a coordinating solvent (i.e. high boilingpoint long chain amine) using zinc stearate and elemental sulfur as the precursors. Spherical ZnS
nanoparticles (~2nm) were obtained and characterized using several different techniques (XRD,
SEM, TEM and UV-Vis). Fluorescence intensity and decay rate of ZnS were acquired using a
fluorometer. The ZnS nanoparticles have a good fluorescence at 400 nm and a long decay time
(~2.5ms). The fluorescence intensity and decay time are inversely proportional to the dissolved
oxygen concentration. Calibrating this relationship allows one to determine the concentration of
dissolved oxygen by measuring the fluorescence intensity and/or the fluorescence decay rate.
The slow decay rates and bright fluorescence make ZnS nanoparticles potential probes for
measuring supersaturated dissolved oxygen, which is difficult to obtain using other techniques.
4-29
Hybridization of DNA Functionalized Silver and Gold Nanoparticles in Aqueous
Dispersions and on Gold Films
Iryna Tokareva, ELIZA HUTTER, Department of Chemistry, Clarkson University, Box 5814,
Potsdam, NY, huttere@clarkson.edu
Silver and gold nanoparticles were successfully functionalized by 12mer oligonucleotides and
hybridized onto gold nanoparticles in dispersions. The optical and hybridization properties of
DNA linked gold-silver ,silver-silver and gold-gold colloidal nanoparticles are described. In
addition, the self-assembly of homo-oligonucleotides on gold films and their hybridization with
their complementary pairs, unlabeled or labeled by gold and silver nanoparticles, were detected
by Polarization Modulated Fourier Transform Infrared Reflection Absorption Spectroscopy (PMFTIRRAS). PM-FTIRRAS was found to be capable to detect the base pairing between DNA
strands and distinguish between the types of oligonucleotides (adenine or thymine) attached to
the nanoparticles.
4-30
Novel Evaluation Method of Nanoparticle Dispersibility in Nanocomposites
by TEM-Computerized Tomography and 3D Image Analysis
H. SASAKURA1, H. Yoden2, S. Noda3, Y. Yamaguchi3, 1Japan Chemical Innovation Institute,
The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan, 2Japan Chemical
Innovation Institute, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima, Japan,
3
Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, BunkyoKu, Tokyo, Japan, sasakura@chemsys.t.u-tokyo.ac.jp
We propose a novel evaluation method to characterize three-dimensional (3D) structures of
nanoparticles in nanocomposites by using 3D images obtained from a transmission electron
microscopy assisted by computerized tomography (TEM-CT). Since physical properties such as
transparency, dimensional stability and thermal durability depend on the dispersibility of
nanoparticles in a nanocomposite, it is crucial to reveal the 3D structures of nanocomposites.
The silica nanoparticle/epoxy nanocomposite evaluated is a model material to figure out our
proposed method. First, the nanocomposite 3D images are reconstructed by TEM-CT. Second,
the nanoparticle images are separated from the nanocomposite by binarization. Third, the
summation of the shortest distances between each separated particle is normalized by an ideal
distance between two particles under fcc structure, which is defined as Universal Factor (UF) as
an index of the particle dispersibility to quantitatively evaluate the 3D structure of nanoparticles.
It is found that silica nanoparticles in the nanocomposite are well dispersed because the UF of
the nanocomposite is 0.85.
We also show the simple analytical validation in order to estimate the error of the length subject
to the novel evaluation method.
4-31
Systems Based on Polymeric Surfactant – Polyvinylpyrrolidone and Organic Reagents:
Properties and Utilization in Analysis
O.V. MIKULENKO, F.A. Chmilenko, Department of Analytical Chemistry, Dnepropetrovsk
National University, Dnepropetrovsk, Ukraine, analyt@ff.dsu.dp.ua
The influence of polymeric surfactant - polyvinylpyrrolidone (PVP) for various molecular
masses (8103 - 360103) on spectroscopic, protolytical and complex formation properties of
organic reagents (dyes of different classes) is established with the methods of UV-, visual and
IR-spectroscopy. It is shown that addition PVP in solution of azo-, triphenylmethane and
trioxyfluorone dyes leads to shift of absorption strips maximum of reagents, displacement of
reagent dissociation. One can use PVP to modify complex formation of organic reagents with
ions of metals: it is shown in increase of contrast and sensitivity of analytical reactions. On the
basis of PVP adducts with organic reagents we propose manufacturing of electrochemical
sensors for direct determination of polymer content in solution. The conditions of sensors work
are established in model and real solutions of medicine. The complex techniques of spectroscopy
and electrochemical determination of PVP concentration in medicine, bioobjects, waste water,
spectrophotometry techniques of determination of average molecular mass of PVP in substation
and metal ion content in different objects are developed.
5-01
Block Copolymer Directed Self-Assembly of Drug Nanoparticles
Jessica L. Anacker1, Christopher W. Macosko2, ROBERT K. PRUDHOMME3, Thomas R.
Hoye4, Walid S. Saad3, 1Ecolab Research Center, Ecolab, 655 Lone Oak Drive, Eagan, MN,
2
Departments of Chemical Engineering and Materials Science, University of Minnesota,
3
Department of Chemical Engineering, Princeton University, 4Department of Chemistry,
University of Minnesota, prudhomm@princeton.edu
Nanoparticle formulations of drugs, printing inks, sun screens, and other hydrophobic organic
compounds have distinct advantages in bioavailability, color intensity, and aesthetics, for
example. Common requirements of these applications are control of particle size and surface
functionality. Commonly used techniques for the production of nanoparticles include salting out,
solvent-evaporation, and emulsification-based methods. However, these methods have serious
limitations, including long processing times, process scale-up, low nanoparticle drug loading,
and lack of controlled nanoparticle size. In order to overcome these limitations, we describe, an
easily scalable Flash Nano Precipitation process to produce stable, high concentration, and high
drug loading nanoparticles using amphiphilic diblock copolymers. Uniform particles with
tunable sizes from 50-500 nm can be prepared. The rules controlling particle formation will be
presented using block copolymers as the structure-directing species. The process requires control
of three time scales: micromixing times to initiate nucleation, nucleation and growth times for
the drug compound, and block copolymer micellization times.
5-02
Enzymatic Cleavage of Surface-Immobilized Substrates: Effect of Substrate AdsorbedLayer Age
T. F. Svitova, H.W. Blanch, C.J.RADKE. Chemical Engineering Department, University of
California, Berkeley, CA, radke@cchem.berkeley.edu
Proteolytic enzymes are common components of automatic dishwashing and laundry
formulations used to remove protein stains. However, understanding is lacking of their
adsorption and kinetic behavior at surface-bound proteins. Using optical waveguide lightmode
spectroscopy (OWLS), we study the proteolysis kinetics of subtilisin on surface-immobilized
protein substrates including ovalbumin, BSA and beta-casein. We focus specifically on the age
of the surface-immobilized protein by measuring the transient protein-layer mass and thickness
after 4 and 22 hours of protein adsorption. The rate of proteolysis increases linearly with enzyme
concentration for both the 4- and 22-hr adsorbed protein substrate. Surface cleavage rates are
compared to the corresponding bulk proteolysis rates, as gauged by fluorometry with FITClabeled proteins. We argue that structure changes of the proteins upon adsorption influence the
proteolysis rates. Longer aging times permit continuing protein unfolding and interfacial
rearrangement that further decreases the cleavage rate. This hypothesis is supported by
companion interfacial-elasticity measurements for the same proteins adsorbed at the air/water
interface as a function of aging time. A simple Langmuir-Michaelis-Menton kinetic model is
proposed to describe the kinetics of the simultaneous enzyme adsorption and substrate cleavage
of the surface-immobilized protein layers.
5-03
Liquid Core - Polymer Shell Particles
Rob Atkin, Peter Dowding, Andrew Loxley, BRIAN VINCENT, David York*, School of
Chemistry, University of Bristol, Bristol, United Kingdom, * P&G Technical Center, Newcastleon-Tyne, United Kingdom, brian.vincent@bris.ac.uk
Core-shell particles (microcapsules), dispersed in water, with liquid cores and polymer shells of
controlled thickness and morphology, are excellent candidates for the controlled release of
"active" molecules, such as pharmaceuticals, agrochemicals, perfumes, flavors, dyes, inks, etc.
Various methodologies have been reported for making such capsules. In this paper we will
discuss a novel method for the preparation and characterization of a variety of different
microcapsules, including ones with oil cores and others with aqueous cores, depending on the
nature of the active material to be released. The general method used for their preparation is
based on internal phase separation of the polymer wall from the droplets of either an oil/water
emulsion or a water/oil emulsion depending on the nature of the internal phase required. For the
aqueous core particles, the external oil phase is replaced (after shell formation) by an aqueous
phase. Control of the various interfacial tensions is critical in obtaining particles with a shell
(rather than an “acorn” structure”). The size of the microcapsules, and the polymer wall
thickness and permeability can be readily controlled using this method. Characterization of the
microcapsules is mainly based on light scattering, optical microscopy and SEM (of the broken
microcapsules).
Some data will be presented for release rates and amounts of model active materials, and how
this is affected by changes in the various system parameters, such as the size of the liquid core,
the polymer shell thickness, and the nature of the polymer shell.
5-04
Effects of Surface Properties on Droplet Formation Inside a Microfluidic Device
Benjamin Steinhaus1, AMY SHEN2, Patrick Spicer3, 1Dept. of Mechanical Engineering,
Washington University, St. Louis, MO, 2Dept. of Mechanical Engineering, Washington
University, St. Louis, MO, 3P & G, Complex Fluids group, aqshen@me.wustl.edu
Micro-fluidic devices offer a unique method of creating and controlling droplets on small length
scales. A microfluidic device is used to study the effects of surface properties on droplet
formation of a 2-phase flow system. Four phase diagrams are generated to compare the dynamics
of the 2 immiscible fluid system (silicone oil and water) inside microchannels with different
surface properties. Results show that the channel surface plays an important role in determining
the flow patterns and the droplet formation of the 2-phase fluid system. The surface effect on the
droplet deposition inside microchannels will also be discussed.
5-05
Delivery of Food Antimicrobials in Micellar Surfactant Systems
JOCHEN WEISS, Food Biophysics Laboratory, Department of Food Science, University of
Massachusetts, Chenoweth Lab 234, 100 Holdsworth Way, Amherst, MA,
jweiss1@foodsci.umass.edu
Foodborne illness continues to be a problem in the US. Effective and simple processor-level
control measures for foodborne pathogens are urgently needed. Naturally occurring food
antimicrobials offer a convenient mean to improve the safety of the US food supply. While these
compounds have shown to inhibit or kill foodborne pathogens in model microbiological systems,
their widespread use has been limited by general lack of activity and low solubilities. We suggest
that lack of activity of food antimicrobials can be overcome by encapsulating antimicrobials in
delivery systems that are capable of targeting pathogens while decreasing interaction with
interfering food components. We report recent results on the use and efficiency of micellar
surfactant systems as delivery vehicles for lipophilic food antimicrobials. The encapsulation
mechanism and inhibitory efficacy of phytophenol antimicrobials eugenol and carvacrol in two
food surfactants, Surfynol 465 and 485 was investigated. Combinations of
surfactant/phytophenol antimicrobials yielded greatly improved activity in model
microbiological systems with Eugenol-Surfynol 465 having the highest observed activity and
successfully inhibiting Escherichia coli O157:H7 and Listeria monocytogenes. Testing in model
food system (skim, 2% and whole milk) indicated that activity while slightly lower than in model
microbiological system was maintained in skim and 2% milk, but activity in whole milk was
reduced. Reduction of activity is explained in terms of de-micellization and adsorption of
surfactant monomers at milk fat droplet interfaces. Results are promising in that development of
novel antimicrobial delivery systems offers a potentially simple and affordable solution to
improve the safety of fresh and processed food products.
5-06
Formation Mechanism and Properties of Colloidal Nanoparticles used in Lubricant
Additive Formulations
PETER J. DOWDING, Christopher J. Adams1, Brian H. Robinson, David C. Steytler2, 1Infineum
UK Ltd., Milton Hill Business & Technology Centre, P.O. Box 1, Abingdon, United Kingdom,
2
School of Chemical Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom,
Peter.Dowding@Infineum.com
Additives are used in lubricant systems to minimise destructive processes in the engine (e.g.
wear and corrosion) and to confer beneficial properties (e.g. more uniformed viscosity with
temperature and improved fuel economy). Overbased detergents are an integral element of such
additive systems, and consist of surfactant stabilised inorganic nanoparticles (comprising
calcium carbonate). Such “overbased” additives represent “model” hard-sphere systems with
narrow polydispersity and mean core radius in the range 2 – 5 nm. They have been characterised
by a range of techniques including small-angle neutron scattering (SANS). Overbased detergents
are used in lubrication packages to neutralise acid species introduced into the lubricant through
acidic blow-by gases. In addition, the detergent helps maintain piston cleanliness.
The production of stable nanoparticles (with tailored properties) is an area of current research
interest, with potential for a wide range of future applications. For many such systems, a major
challenge is the production of particles with consistent quality (and low polydispersity) on a
large scale. Overbased detergents are produced on a multi-tonne scale, with a constant particle
size and low degree of polydispersity. The mechanism by which such nanoparticles are formed
has recently been investigated by small angle neutron scattering and evidence will be presented
that suggests the particle formation mechanism is via nucleation-growth (and not the previously
reported micellar route). A similar synthesis mechanism may have potential for other inorganic
nanoparticles.
In addition, characterisation of the properties of such detergent particles (e.g. core and surfactant
shell sizes by SANS) will also be presented.
5-07
The Synthesis of FePt Nanoparticles by Two-Liquid Mixing Method
TORU IWAKI, Kanae Yuasa*, Kikuo Okuyama**, *Dept. Chem. Eng., Hiroshima Univ.,
Kagamiyama 1-4-1, Higashi-Hiroshima, Japan, **Japan Chem. Innovation Inst., 1-3-1
Kagamiyama, Higashi-Hiroshima, Japan, iwaki@nanoparticle.jp
FePt nanoparticles have been synthesized continuously by mixing two precursor liquids: ferric
acetylacetonate, Fe(acac)3 , and platinum acetylacetonate, Pt(acac)2 in ethyleneglycol solution
with dispersing agents. The reduction reaction of the mixed Fe and Pt ions to the FePt metal
alloys in the reaction cell at a high temperature were aided by irradiating the high power of
ultrasound continuously. The obtained FePt particle size was found by TEM photograph to be
around 3~ 4 nm showing monodisperse and nonagglomerating. The rate of production of the
FePt nanoparticles was more than 30g per hour. The composition of Fe and Pt elements in FePt
nanoparticles determined by ICP analysis was changed arbitrarily by controlling the flow rate of
two precursor liquids. The ferromagnetic property of FePt nanoparticles was obtained by the
annealing because as grown sample shows the nature of super-paramagnetic properties. The
annealing condition was to keep the FePt nanoparticles at a high temperature for 30 min in an
atmosphere of 15% of H2 and 85% of Ar. The magnetic hysteresis loops of FePt nanoparticles
were obtained by SQUID measurements. The highest room temperature coercivity ~up to 10 kOe
was observed in Fe53Pt47 sample.
The addition of Ag atoms to FePt nanoparticles in the nanoparticles synthesis lowered the
annealing temperature of the sample as low as below 350°C. The magnetic properties of the
FePtAg and FePt nanoparticles were compared by the measurements of SQUID and XMCD.
5-08
Mesoscale Simulation of Colloids and Surfactants in Consumer Products
FIONA CASE, Case Scientific
Many soft or fluid consumer products, such as foods, paint, detergents, personal care products,
and cosmetics, contain nanometer to micron size fluid structures. These structures (such as
micelles, vesicles, emulsions and lamella) are formed by the spontaneous self-assembly of
natural or synthetic surfactants or block copolymers. In many cases complex mixtures of
different surfactants and polymers are required to create the desired structure and performance.
These complex materials are challenging to characterize. Even with the latest developments in
light microscopy the fluid structures can be orders of magnitude too small to be observed.
Illumination with smaller wavelength radiation (such as x-rays or neutrons) solves the size
problem, but results can only be interpreted unambiguously for simplified model systems.
Adding to this challenge is the fact that product performance depends not on the static or
equilibrium structure of the material, but on its dynamic behavior. When detergent cleans, or
soap foams, or a fragrance releases, or margarine spreads, it is the way that the nanometer to
micron sized fluid structures change in response to external stimuli that determines performance.
How can we predict the dynamic nanometer to micron scale structure of a particular mixture of
surfactants, polymers, oils and additives – of a particular formula? And how can we predict its
response to external stimuli - agitation, dilution, or the introduction of a dirty surface? If we
could do this, and we could also identify the link between physical properties and consumer
perceivable performance (another significant challenge!), we could prescribe the perfect formula
for any application.
Computer simulation may provide part of the solution by predicting the structure and dynamic
behavior of materials. There are a number of different types of simulation. Atomistic scale
simulation methods are quite well established. They can reliably predict the shape of individual
molecules or relatively small clusters of molecules. Using a super-computer, such as IBM’s Blue
Gene/L prototype, the structures of lipid membranes and membrane proteins can even be
predicted. These methods can provide insight into part of the problem (the behavior of small
fluid structures, over the short periods of time). The much larger scale mixing and flow of
materials can be predicted using methods such as computational fluid dynamics, this is another
part of the solution. But CFD alone cannot predict the effects of varying molecular structure on
the performance of a material (for example of changing the type of surfactants in a complex
mixture). Mesoscale modeling techniques, such as dissipative particle dynamics and mean-field
theories, have proved capable of modeling a critical length scale for complex fluids – capable of
predicting the self assembly of structures from nanometers to microns in size. This presentation
will provide an overview of different computational approaches, focusing on mesoscale
modeling and its potential application to predict properties of personal care products such as
liquid soaps and detergents. We will also look to the future, and to the development of new
approaches that combine the different length scales in one simulation. These new methods may
finally allow us to predict the behavior of the fascinating, complex, dynamic materials that are
modern consumer products.
5-09
Fluorescent Silica Colloids for Detection of Absorption of Various Skin Care Products
S. Iyer, Ya. Kievesky, I. SOKOLOV, Clarkson University, Potsdam, NY,
isokolov@clarkson.edu
Recently we have synthesized a new type of very bright nanoporous silica colloids. Organic
lasing dye is encapsulated inside of closed pores, which prevents its leakage. Silica particles are
chemically inert and rather biocompatible. It makes them a good candidate for tracing of various
substances, in particular, skin-care products. To demonstrate this, we mix the silica particles with
two types of moisturizers broadly used in cosmetics, Vaseline and glycerin. We demonstrate that
the amount and location of the moisturizers on human skin can now be easily detected with UV
light source. The absolute radiance measurements show a good correlation with amount of the
moisturizers measured by collecting-by-scratching tests. The presented method can be
effectively used for a fast non-contact detection of location of the skin-care products, its spread
with time, and absorption by skin.
5-10
Colloidal Nanoparticles in Consumer Products
KRASSIMIR P. VELIKOV, Tim Foster, Clive Marshman, Eddie Pelan, Food Research Center,
Unilever Research & Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The
Netherlands, Krassimir.Velikov@Unilever.com
Colloidal nanoparticles have found many applications in a broad range of technologies and in the
processing of various materials including foods, cosmetics, paints, and drug delivery systems. In
addition, due to their ability to assemble in bulk and at interfaces they are widely used as a
precursor for advanced nanostructured materials. In consumer products, colloidal nanoparticles
are either naturally present, formed during the processing, or intentionally added to tailor certain
functional properties of the product. In this presentation, we will discuss the fundamental
approaches to control product functionality like composition, structure, stability, taste and
appearance.
6-1
Polymerized Colloidal Array Photonic Crystal Chemical Sensors
SANFORD A. ASHER, Department of Chemistry, University of Pittsburgh, Pittsburgh, PA,
asher@pitt.edu
We have developed a novel class of smart optical materials based on soft materials which are
responsive to their environment and which can be actuated chemically or photonically. Highly
charged, monodisperse colloidal particles will self assemble in water into crystalline colloidal
arrays (CCA), which are either body centered or face centered cubic structures. We have
developed smart materials from these self-assembled structures, which utilize the highly efficient
Bragg diffraction of light from the CCA periodicity. We polymerized these CCA into
acrylamide hydrogels. These CCA-embedded hydrogels show the rich volume phase transition
phenomena characteristic of these soft materials. These materials act as frequency agile optical
filters. We have functionalized these hydrogels with dyes and photochromic molecules, as well
as with molecular recognition agents which cause the hydrogel to change volume in response to
either photons, or the presence of specific analytes (eg Pb2+, glucose etc). The resulting volume
changes alter the array spacing, which causes the diffracted light wavelength to shift, or causes
the diffraction efficiency to change. We will discuss the volume phase transition properties of
these arrays and also describe the use of these arrays and also describe the use of these arrays as
chemical sensors, novel ns optical switching materials as well as optical memory devices.
6-2
Lyotropic Liquid Crystal Templating of Mesoporous Hollow Spheres: A New Route to
Materials for Controlled Release and Encapsulation?
A. Wolosiuk, P. V. BRAUN, Department of Materials Science and Engineering, Materials
Research Laboratory, and Beckman Institute, University of Illinois at Urbana-Champaign,
Urbana, IL, pbraun@uiuc.edu
Hollow spheres (500 nm diameter) containing a periodic array of 3 nm pores in a hexagonal
lattice in the shell wall were created through liquid crystal templating of the growth of ZnS on
polystyrene and silica colloidal particles, followed by dissolution of the colloidal particle. The
colloidal particles were first dispersed into a lyotropic liquid crystal formed from a nonionic
surfactant and water that also contained thioacetemide and zinc acetate. Then, ZnS, formed from
the reaction of thioacetemide and zinc acetate, heterogeneously deposited in a superlattice
structure as defined by the liquid crystal on the surface of the colloidal particles. The
mineralized colloidal particles were separated from the liquid crystal, and the colloidal particles
were dissolved, resulting in a hollow sphere perforated with a periodic array of nanoholes. Both
silica and polystyrene colloidal particles could be used as templates; silica particles are removed
with fluoride ions, while polystyrene particles are removed with organic solvents. Initial
experiments which demonstrate the sequestering of macromolecules within the mesoporous
hollow spheres while permitting the passage of smaller molecules will be described.
6-3
Rippled Metal Nanoparticles: A New Protein Resistant Material
ALICIA JACKSON, Francesco Stellacci, Department of Materials Science and Engineering,
MIT, Cambridge, MA, frstella@mit.edu
Here we present a new family of mixed ligand nanoparticles that shows sub-nanometer patterns
(e.g. ridges) on their ligand shell. This unique sub-nano-structuring of their ligand shell provides
new properties to the particles. In particular, we focus on silver and gold particles that have
ridges composed of hydrophilic valleys and hydrophobic peaks. We will show the ability to
control the supramolecular ordering of the ligands on the nanoparticle surfaces. Indeed, by
systematically varying the mixture of ligands introduced during nanoparticle synthesis, one can
control the resulting surface properties of the nanoparticles. Scanning tunneling microscopy
images show ridges 3 Å deep and 6 Å wide on the ligand shell of nanoparticles. Control of both
these parameters is provided by the choice of the ligands and of their molar ratio respectively.
We also demonstrate that the nanoparticle ligands interact so as to align the stripes of
neighboring nanoparticles over large length scales. The synthetic mechanism that leads to the
formation of this supramolecular ordering will be discussed. These particles show unique and
unexpected wettability, solubility, self-assembly and surface chemistry properties. They, also,
show a remarkable resistance to protein nonspecific adsorption, one order of magnitude better
than state of the art antifouling materials.
6-4
Fluorescent Nanoparticles in Cellular Differentiation
B. DUBERTRET, CNRS, Laboratoire d’Optique Physique, ESPCI 10 rue Vauquelin, 75005,
Paris, France, benoit.dubertret@espci.fr
We encapsulate individual nanocrystals in phospholipid block-copolymer micelles, and
demonstrate both in vitro and in vivo imaging. When conjugated to DNA, the nanocrystalmicelles act as in vitro fluorescent probes to hybridize to specific complementary sequences.
More importantly, when injected into Xenopus embryos, the nanocrystal-micelles are stable, nontoxic (<5x109 nanocrystals per cell), cell autonomous, and slow to photobleach. Nanocrystal
fluorescence can be followed to the tadpole stage, allowing lineage tracing experiments in
embryogenesis. We show that nanocrytal size is a crucial parameter that determines the particle
localization during the embryo development.
6-5
Nano-Pumps in Hydrogels: Electroosmotic Mass Transport Control
MARVI A. MATOS1, Robert D. Tilton1,2, Lee R. White1, Center for Complex Fluids
Engineering, 1Department of Chemical Engineering, 2Department of Biomedical Engineering,
Carnegie Mellon University, Pittsburgh, PA, mmatos@andrew.cmu.edu
Gels are a common matrix for biosensors. Hindered transport through the polymeric matrix
slows down the response rate in such sensors. As the number of diagnostic and analytical
applications for gel-based sensor devices increases, so does the necessity of new pumping
mechanisms for faster response. The network and mechanical properties of the gel make
mechanical mixing schemes inappropriate. We are investigating novel internal pumping
strategies based on electrically driven convection as a way to accelerate mass transfer in
polyacrylamide gels. The gels are doped with charged silica colloids that drive local
electroosmotic flow in response to externally applied electric fields. The uniformity of the
particle dispersion throughout the gels is investigated by small angle neutron scattering. We use
fluorescence spectroscopy to measure the mass transport of a fluorescent dye, aminomethylcoumarin, in these gels as a function of particle loading and applied field strength.
Studies of silica particles with different sizes show that the electroosmotic mass transport
enhancement is strongest when using nanoscale silica particles. We are also investigating the
effects of electrolyte concentration on the electroosmotic pumping effect.
6-6
Highly Luminescent Nanoparticles for in Vivo Cancer Imaging and Detection
WEI CHEN, Nomadics Inc., 1024 South Innovation Way, Stillwater,
wchen@nomadics.com
OK,
Deep-tissue optical imaging is of particular interest, as the equipment costs are lower than for
competing technologies such as magnetic resonance imaging. For this purpose, the development
of novel contrast agents with near-infrared (NIR) fluorescence is especially important. We
report on the use of NIR and upconversion semiconductor nanoparticles in deep-tissue in vivo
optical imaging. Semiconductor nanocrystals of CdMnTe/Hg were grown in aqueous solution
and then coated with bovine serum albumin (BSA). The nanocrystals were approximately 5 nm
in diameter and have a broad fluorescence peak in the NIR (770nm). Nanocrystals were injected
either subcutaneously or intravenously into athymic mice and then excited with a spatially broad
633 nm source; the resulting fluorescence was captured with a sensitive CCD camera. We have
demonstrated that the nanocrystals are a useful angiographic contrast agent for vessels
surrounding and penetrating a murine squamous cell carcinoma in a C3H mouse. Preliminary
assessment of the depth of penetration for excitation and emission was done by imaging a
beating mouse heart, both through an intact thorax and after a thoracotomy. The temporal
resolution associated with imaging the nanocrystals in circulation has been addressed, and the
blood clearance for this contrast agent has also been measured. There was no significant
photobleaching or degradation of the nanocrystals after an hour of continuous excitation. The
stability of the nanocrystals together with the time resolution of the optical detection makes them
particularly attractive candidates for pharmacokinetic imaging studies. The author would like to
thank the supports by NIH and Army Medical for grants and his NIH partners for collaborations.
6-7
Harnessing Nanoparticles for Glycobiology
THANH K. T. NGUYEN, David G. Fernig, Centre for Nanoscale Sciences, School of
Biological Sciences and Department of Chemistry, University of Liverpool, BioSciences
Building, Crown Street, Liverpool, United Kingdom, ntkthanh@liv.ac.uk
In this paper, we would like to present a new method to stabilise and functionalise nanomaterials
(Au nanoparticles, semiconductor Q-dots, and magnetic nanoparticles Co using a “peptide
toolbox”. The peptides play three important roles during synthesis: (i) control of the nucleation
and growth processes to produce the desired morphology and internal structure; (ii) protect the
nanoparticle/cluster cores from chemical degradation and maintain their physical stability
(dispersion) in aqueous and biological environments; (iii) to allow functionalisation. For ligand
exchange only (ii) and (iii) apply. The ability to tune the properties of the peptides (by varying
the length, and sequence of amino acids makes them a unique class of ligands for combinatorial
nanomaterial synthesis.
Heparan sulfate proteoglycans (HSPGs), which are strategically located on the surface of
mammalian cells, act as regulators of most aspects of cell behaviour and function are involved in
the pathology of many disease. The regulatory properties of HSPGs are thought to depend upon
the fine structure of the HS glycosaminoglycan chain. Analysis of the structure and function of
HS is hampered by the fact that their synthesis is not template driven. There is no amplification
step, which would allow analysis of single structures produced by a biologically defined unit
such as a cell or group of cells. Consequently, only abundant sources of material representing an
average of structures may be analysed.
Nanoparticles offer the possibility of single particle detection that permits the analysis of
polysaccharide chains at a hitherto unachievable sensitivity, which will open up new
experimental approaches in glycobiology.
6-8
Semiconductor Nanocrystals and Their Practical Applications
L. BROGAN, Evident Technologies, Inc. 216 River Street, Troy, NY, lbrogan@evidenttech.com
Semiconductor nanocrystals have been the subject of research for decades. Recently, we have
witnessed the advent, prototyping and commercialization of quantum dot based products. Since
quantum dots represent a tunable band gap semiconductor material, they have inherent
advantages over traditional semiconductors with fixed bandgaps. Quantum confinement allows
us to tune the electronic structure based on size of the crystal as long as the physical size is less
than the exciton Bohr radius. Many people are capitializing on this quantum mechanical feature
and fashioning these quantum dots into products from in vivo diagnostics to thermoelectrics,
night vision pigments to wear indicators, LEDs to sunscreens. The compelling features of
tunable electronic and optical properties along with their colloidally grown form factor makes
them an enabling material for many new markets. For diagnostic applications in the life
sciences, quantum dots are a natural as they give unlimited emission wavelengths, legendary
photostability, broad excitation, and are “relatively” simple in that they are sold as a colloidal
suspension. The tunable emission wavelengths allows thing like deep tissue imaging since NIR
emission wavelengths are possible, which transport through tissue without scattering. The
photostability is called upon in live and fixed cell imaging applications that require extended
interrogation under illumination. Broad excitation and emission color variety enable color
multiplexing for higher throughput screening. These are no longer research materials since they
are commercially available today. The potential for these materials has yet to be fully realized.
We are at the headwaters of the development of nanocrystal products.
6-9
Quartz Crystal Microbalance Detection of Peptide Epitope Protected Nanoclusters Using
Antibody Recognition
A. E. Gerdon, D. E. Cliffel, D.W. WRIGHT, Department of Chemistry Vanderbilt University,
Nashville, TN, david.wright@vanderbilt.edu
A quartz crystal microbalance (QCM) sensor was developed for the quantitative detection of
peptide epitope-protected nanoclusters. We have addressed challenges in the area of QCM mass
sensing through experimental correlation between damping resistance and frequency change for
a reliable mass measurement. Electrode functionalization was optimized with the use of Protein
A to immobilize and present polyclonal IgG for antigen binding. This method was developed for
the detection of glutathione (antigen) protected clusters of nanometer size with high surface area
and thiolate valency. Quantitation of glutathione-nanocluster binding to immobilized polyclonal
antibody provides equilibrium constants (Ka = 3.6 + 0.2 x 105 M-1) and kinetic rate constants (kf
= 5.4 + 0.7 x 101 M-1s-1 and kr = 1.5 + 0.4 x 10-4 s-1) comparable to literature reports. Additional
studies using conformational or linear peptide epitopes from the protective antigen (PA) of B.
anthracis presented on the surface of monolayer protected clusters to produce functional
nanostructures identified one monoclonal anti-PA antibodies to be specific for the
conformational loop structure PA680B. Quantitative studies using a quartz crystal microbalance
immunosensor confirmed specificity. These results demonstrate an ability to map monoclonal
antibody recognition to specific epitope structures on nanoparticles.
6-10
Tumor-targeted Gadolinium Nanoparticles for Neutron Capture Therapy and for MRI
Contrast Enhancement
MICHAEL JAY, Donghua Zhu, Moses Oyewumi, Russell J. Mumper, Department of
Pharmaceutical Sciences, University of Kentucky, Lexington, KY, jay@email.uky.edu
Gadolinium can be used in neutron capture therapy (NCT) in which Gd, if directed to tumors in
sufficiently high concentrations, can capture thermal neutrons resulting in the emission of tumordestructive electrons. Gd is also an effective contrast agent in Magnetic Resonance Imaging.
Nanoparticles containing Gd in the core or bound to the surface were engineered from oil-inwater microemulsion templates.
A folic acid ligand chemically linked to
distearoylphosphatidylethanolamine via a PEG spacer was used to obtain tumor-targeted folatecoated nanoparticles. These were characterized based on size distribution, morphology,
biocompatibility and tumor cell uptake. The Gd nanoparticles did not aggregate platelets or
activate neutrophils. These nanoparticles were shown to have enhanced retention in the
circulation as well as increased tumor uptake in tumor-bearing athymic mice, thus exhibiting
potential of enhancing the therapeutic success of NCT. Nanoparticles in which Gd was bound to
the surface via DTPA moieties were shown to greatly enhance the contrast of T2-weighted, spin
echo images. These particles have potential for use in MRI blood pool imaging as well as in the
imaging of tumors via the Enhanced Permeation and Retention mechanism.
6-11
Strategies for On-Chip Assembly of Sensors and Biomaterials from Live Cells
O. D. VELEV, S. Gupta, R. G. Alargova, L. B. Jerrim, P. K. Kilpatrick, Department of Chemical
and Biomolecular Engineering, North Carolina State University, Raleigh, NC,
odvelev@unity.ncsu.edu
New techniques of assembly of biosensors, nanostructures and nanodevices from live cells will
be presented. They are based on principles for nanoparticle assembly into well defined 2D and
3D structures that we have developed earlier. We demonstrate how on-chip dielectrophoresis can
be used to co-assemble yeast cells and synthetic micro- and nanoparticles. Depending on the
frequency of the field and relative polarizability of the cells and particles, one and two
dimensional arrays can be obtained. These arrays can be bound into permanent biocomposites by
using molecular recognition. Such cell-nanoparticle chains and membranes can form the basis of
sensors, microscopic bioreactors and artificial tissue. We also present a method for assembling
and immobilizing large-scale coatings from yeast cells. The coating method is based on
convective assembly and deposition in a moving meniscus to make dense two-dimensional
arrays. A robust technique for rapid deposition of monolayer cell coatings was designed on the
basis of this method. One immediate application of these structures is in biosensors and test beds
for toxicity and drug action. The coassembly of live cells and synthetic nanoparticles also yields
new biomaterials, in which the functionality of the cells is coupled to the functionality of the
nanoparticles.
6-12
Custom BeadChip Technology for Molecular Diagnostics
SUKANTA BANERJEE, BioArray Solutions, Warren, NJ, sukanta.banerjee@bioarrays.com
BioArray Solutions (BAS) has developed unique, proprietary technologies for the rapid and
flexible analysis of DNA, proteins and cells on semiconductor chips. Our diagnostic platform
combines semiconductor physics, extensive bead chemistry and molecular biology to bring
unparalleled flexibility and performance to quantitative DNA, protein and cellular analysis.
BAS’ proprietary array manufacturing process includes an evolutionary, two-track
manufacturing process that combines wafer-scale assembly with custom bead array production to
provide "last-second" customization for maximum flexibility at the lowest possible cost.
Thousands of arrays can be produced simultaneously. By arranging large numbers of particles
into small areas of the substrate, hundreds to thousands of binding events may be monitored
simultaneously. In one standard assay format, a standard CCD camera, in conjunction with an
optical microscope, in a single snapshot records 4,000 binding events. With its BeadChip TM
assays for genomics and proteomics, BioArray Solutions addresses the challenge of high
performance accuracy in multiplexed assays, high patient sample volume and rapid response
time.
6-13
Multi-Responsive Microgels: Morphology Control for Optimized Applications
TODD HOARE, Robert Pelton, Department of Chemical Engineering, McMaster University,
Hamilton, ON, Canada, hoaretr@mcmaster.ca; peltonrh@mcmaster.ca
Carboxylic acid-functionalized poly(N-isopropylacrylamide) (PNIPAM) microgels exhibit
“smart”, rapid, and reversible responses to changes in temperature, pH and ionic strength. To
achieve a targeted set of environmental responses and optimize microgel morphologies for
particular applications, one must control not only the bulk content but also the radial and
intrachain distributions of functional groups within the microgel matrix, distributions which we
have shown to play integral roles in regulating the properties of functionalized microgels. We
have developed methods of controlling functional group distributions in carboxylic acidfunctionalized PNIPAM-based microgels by tuning the hydrophobicity and copolymerization
kinetics of the functional comonomer. The resulting functionalized microgels are extensively
characterized, both directly via electron microscopy and indirectly using electrophoresis,
titration, calorimetry, light scattering, and rheological techniques. Novel dimensionless plotting
strategies allow us to directly compare the microscale and macroscale development of both the
thermal and pH-induced transitions, giving insight into both the functional group distributions
within the microgels and the underlying mechanisms of microgel swelling. The key influence of
the radial and intrachain functional group distributions in the application performance of
carboxylic acid-containing microgels is also specifically illustrated by testing the utility of the
microgels as drug uptake/delivery vehicles and bioactive molecular conjugation supports.
6-14
Design of Quantum Dot-Protein Bioconjugates for Use in FRET-Based Assays
A.R. Clapp, I.L. Medintz, E.R. Goldman, H. MATTOUSSI, U.S. Naval Research Laboratory,
Division of Optical Sciences and Center for Bio/Molecular Science and Engineering,
Washington, DC, hedimat@ccs.nrl.navy.mil
The unique spectroscopic properties of luminescent quantum dots (QDs), including broad
absorption and size-tunable photoluminescence (PL) spectra ranging from the UV to IR and
exceptional resistance to chemical and photo-degradation, are appealing for use in developing a
variety of bio-inspired applications, ranging from molecular assays to in vivo cellular imaging.
We have developed several approaches based on non-covalent self-assembly to conjugate
biomolecules to CdSe-ZnS core-shell QDs that were rendered water-soluble using multidentate
surface capping ligands. Antibodies were conjugated to these QDs either directly or via a
bridging adaptor protein. QDs conjugated to proteins and antibodies prepared using our
approaches were found to exhibit high specificity and stability in solution-based Förster
resonance energy transfer (FRET) assays. In addition, we found that the readily tunable QD
emission permitted effective tuning of the spectral overlap between the QD donor and dye
acceptor, thus allowing excellent control over the FRET efficiency in these complexes. These
findings were further exploited to design FRET-based nanoscale sensing assemblies for the
specific detection of target molecules in solution. Combined with the advantages of CdSe-ZnS
QDs, these hybrid bioinorganic conjugates represent a very promising tool for use in several
biotechnological applications.
6-15
Up-Converting Phosphorescent Probes for Rapid Diagnostic Assays
SHANG LI, George Giannaras, Ronelito Perez, Mark Fischl, Bonnie Martinez, Keith Kardos,
OraSure Technologies, Inc., 150 Webster Street, Bethlehem, PA, sli@orasure.com
Recent applications of Up-Converting Phosphor Technology (UPTTM) have demonstrated that
up-converting phosphors conjugated to biological-recognizing molecules (such as nucleic acids,
peptides, or antibodies) can be used as alternatives to conventional fluorescent probes for highsensitivity bioassays. In contrast to fluorescent dyes, these phosphorescent probes are excited by
infrared lasers and emit intense phosphorescence in the visible range. Because no biological
matrix possesses this unusual property, autofluorescence is completely absent in the upconverting phosphorescent assays, which makes UPTTM an ideal choice for detecting
biomolecules from complex matrices. A systematic approach for the construction and
characterization of Y2O2S up-converting phosphorescent probes for rapid diagnostic assays will
be presented. Uniform 200 nm Y2O2S particles are synthesized using the homogenous
precipitation method followed by a fluidized bed sulfurization technique. The prepared Y2O2S
powders are chemically stable in the dried form, but degrade slowly in common buffers. The
surface chemistry of Y2O2S can be controlled by encapsulation of particles with a sol-gel silica
coating. Functionalized phosphors particles are made by grafting carboxyl silanes or
polyelectrolytes on the silica surface and subsequently characterized using XPS, zeta-potential,
and spectroscopic methods. Stability and reproducibility of bioconjugated up-converting
phosphorescent probes prepared using carbodiimide chemistry are evaluated in bioassays.
6-16
Block Ionomer Complexes as Novel Nanomaterials
T.K. BRONICH, A.V. Kabanov, Center for Drug Delivery and Nanomedicine, College of
Pharmacy, University of Nebraska Medical Center, Omaha, NE, tbronich@unmc.edu
The block ionomer complexes are spontaneously formed by reacting the block (or graft)
copolymers containing non-ionic and ionic polymeric segments (“block ionomers”) with
oppositely charged species, such as polyions, proteins, surfactant ions, or metal ions. These
complexes belong to the special classes of nanostructured materials combining the properties of
cooperative polyelectrolyte complexes and amphiphilic block copolymers. These materials
exhibit unique self-assembly behavior: they can spontaneously form either colloidal dispersions
(vesicles, micelles, nanoparticles) or nanocomposite bulk materials. If the nonionic block in the
block ionomer is hydrophilic (e.g. poly(ethylene oxide)), the resulting complexes are waterdispersed. A variety of polymer and surfactant components can be used in these composites
allowing adjustment of the materials to respond to environmental changes in broad ranges,
including pH, ionic strength, solvents and temperature variations. If the nonionic block is
hydrophobic (e.g. polystyrene), the self-assembly with oppositely charged polyions leads to
formation of multilayer polyion complex micelles in aqueous dispersion while interaction with
surfactant ions results in formation of block ionomers complexes dispersed in organic solvents.
These materials are promising in addressing various theoretical and practical problems,
particularly, in pharmaceutics, where block copolymers and polyelectrolyte complexes are
already being intensively investigated as drug and gene delivery systems.
6-17
Generation of Functionalized Colloidal Gold Nanoparticles Using Bi-Functional Reducing
Agents
G. F. PACIOTTI, L.D. Myer, V. Silin, L. Tamarkin, CytImmune Sciences, Inc. 9640 Medical
Center Drive, Rockville, MD, gpaciotti@cytimmune.com
Our laboratory is using colloidal gold nanoparticles to develop tumor-targeting nanotherapeutics.
Our first drug uses thiol groups present on the drug’s key components to bind them to the
nanoparticle surface. Yet, we recognize the thiol chemistry alone may limit the types of
therapeutics that can be developed on the platform. To address this question we generated
functionalized colloidal gold nanoparticles that contain a variety of functional groups present on
their surface. Our approach uses bi-functional reducing agents (BFRA) that generate the gold
particle, by reducing gold chloride under reflux, and embed/add functional group(s) on the
particles’ surface. The BFRAs consist of core polymer containing both free thiol groups and
secondary reactive groups. The free thiol groups serve to reduce chloroauric acid into gold
nanoparticles, while the secondary reactive groups present on the polymer are used to bind drugs.
Two chemically distinct classes of BFRAs were used to manufacture the gold particles. The first
type consisted of a 10kD branched-chain polymer of PEG having four thiol groups. The second
reducing agent was synthesized on a polylysine core polymer which was thiolated using
2iminothiolane. The particle size, shape, and drug binding characteristics for various
preparations are described.
6-18
Integration of Biocompatible Surface Chemistries in the BARC Biosensor System
S. P. MULVANEY, C. C. Cole, M. Malito, J. C. Rife, C. R. Tamanaha, L. J. Whitman, Naval
Research Laboratory, Washington, DC, shawn.mulvaney@nrl.navy.mil
We are developing a highly sensitive and selective biosensor system that uses giant
magnetoresistive sensors arrayed in a Bead ARray Counter (BARC™) microchip to directly
detect magnetic microbead labels. The beads are used both to label biorecognition events and as
transduction elements to reduce background through a patent-pending process known as fluidic
force discrimination (FFD). FFD is a controlled bead removal procedure that leverages the
strength of biomolecular recognition against fluidic forces to selectively remove non-specifically
bound bead labels. A number of surface chemistries have been explored to functionalize the
BARC chips, with the best results achieved on Si3N4 terminated chips. Neutravidin is covalently
attached to Si3N4 via glutaraldehyde, and biotinylated capture probes are then employed for
biosensing. Highly sensitive DNA hybridization assays (10 fM) have been performed and the
magnetic sensor signal confirmed with optical bead counting. Application of the BARC
platform for the multiplexed detection of four biowarfare agents without PCR, in 30 minutes, and
at room temperature, will be described, as will preliminary results using similar chemistry for
sandwich immunoassays. This work was supported by ONR, TSWG, and DTRA. SM, CC, and
MM are employees of Nova Research, Inc., Alexandria, VA.
6-19
Quantification of the Field Interaction Parameter and the Binding Constants of Several
Antibody-magnetic Nanoparticle Conjugates
J.J. CHALMERS, H. Zhang, M. Zborowski, Department of Chemical and Biomolecular
Engineering, The Ohio State University, Columbus, OH, and Department of Biomedical
Engineering, The Cleveland Clinic Foundation, Chalmers@chbmeng.ohio-state.edu
It has been previously reported that the magnetophoretic mobility of labeled cells show a
saturation type phenomenon as a function of the concentration of the free antibody-tag conjugate.
Starting with the standard antibody-antigen relationship, a model was developed which takes into
consideration multi-valence interactions and various attributes of flow cytometry and cell
tracking velocimetry, CTV, measurements to determine both the apparent dissociation constant
and the antibody binding capacity of a cell. This model, combined with experimentally obtained
data of the field interaction parameter of specific types of magnetic nanoparticles, was then
evaluated on peripheral blood lymphocytes labeled with anti CD3 antibodies conjugated to
FITC, PE, or DM (magnetic beads). Reasonable agreements between the model and the
experiments were obtained. In addition, estimates of the limitation of the number of magnetic
nanoparticles that can bind to a cell as a result of steric hinderance was consistent with measured
values of magnetophoretic mobility. Finally, a scale up model was proposed and tested which
predicts the amount of antibody conjugates needed to achieve a given level of saturation as the
total number of cells reaches 1010, the number of cells needed for certain clinical applications,
such as T-cell depletions for mismatched bone marrow transplants.
6-20
Preparation of Organic Nanoparticles Using Microemulsions. – Their Potential Use in
Transdermal Delivery
C. Destrée, J. B.NAGY, Laboratoire de RMN, Facultés Universitaires Notre-Dame de la Paix, 61
Rue de Bruxelles, B-5000 Namur, Belgium, Janos.bnagy@fundp.ac.be
Organic nanoparticles of cholesterol and retinol have been synthesized in various
microemulsions (AOT/heptane/water; CTABr/hexanol/water; Triton X-100/decanol/water) by
direct precipitation of the active principle in the aqueous cores of the microemulsion. The
nanoparticles are observed by transmission electron microscope using the adsorption of
contrasting agents such as iodine vapor, osmium tetroxide or uranyl acetate. The size of the
nanoparticles can be influenced, in principle, by the concentration of the organic molecules and
the diameter of the water cores which is related to the ratio R=[H2O]/[Surfactant]. The particles
remain stable for several months. The average diameter of cholesterol nanoparticles is comprised
between 5.0 and 7.0 nm, while that of retinol is smaller, being ca. 2.5 nm. The average size of the
cholesterol nanoparticles does not change much either as a function of the ratio R or of the
concentration of cholesterol. The constant size of the nanoparticles can be explained by the
thermodynamic stabilization of a preferential size of the particles. Different solvents are used to
carry the active principle into the aqueous cores and they do not influence the precipitation
reaction in a significant way.
6-21
Fluorescent Silica Beads for Detection of Cervical Cancer
S. Iyer, Ya. Kievesky, C.D. Woodworth, I. SOKOLOV, Clarkson University, Potsdam, NY,
isokolov@clarkson.edu
We present the use of self-assembled fluorescent silica (glass) beads for detection of cervical
cancer. The cells from three different individuals (3 normal and 3 tumor) were tested for affinity
by using the beads, a few microns glass nanoporous particles which contain fluorescent dyes
sealed inside the pores. Using atomic force microscopy, we studied forces acting between the
silica particles and the cells in-vitro. Using those data, we developed two different methods for
detecting the affinity between silica and cells in-vitro. In one method we use a simple
precipitation of the beads onto the cells, and with subsequent washing, the unbounded beads are
removed. The second method involves using centrifugation for the removal of the unbounded
beads. Both methods show unambiguous identification between the normal and tumor cells.
6-22
Fluorescence Analysis of Polymersome and Filomicelle Delivery
D.E. DISCHER, F. Ahmed, P. Dalhaimer, Chemical and Biomolecular Engineering, University
of Pennsylvania, Philadelphia, PA, discher@seas.upenn.edu
PEG-polyester block copolymers can be made of the right proportion to assemble into controlled
release vesicles and cylinder micelles, or polymersomes and 'filomicelles', respectively.
Comparisons of these two morphologies, in terms of how they interact with cells and how they
behave in vivo, bring new meaning to 'bio-nano'. We make extensive use of fluorescence
microscopy to characterize the degradation and release processes as well as cell entry pathways
in vitro. We also use such methods in vivo to track their fates, allowing us to identify super-long
circulating filomicelles. Emerging tumor studies will be described.
6-23
Superparamagnetic Nanoparticle-bound Chlorotoxin for Brain Tumor Imaging
MIQIN ZHANG, University of Washington, Seattle, WA, mzhang@u.washington.edu
A multifunctional nanoprobe capable of targeting glioma cells, detectable by both magnetic
resonance imaging and fluorescence microscopy was developed. The nanoprobe was synthesized
by coating iron oxide nanoparticles with covalently-bound bifunctional polyethylene glycol
(PEG) which were subsequently functionalized with chlorotoxin, a glioma tumor targeting
peptide, and the near infrared fluorescing molecule, Cy5.5. Both MR imaging and fluorescence
microscopy showed significantly preferential uptake of the nanoparticle conjugates by glioma
cells. Such a nanoprobe can potentially be used to image resections of glioma brain tumors in
real time and to correlate preoperative diagnostic images with intraoperative pathology at
cellular-level resolution.
6-24
Novel Magnetic Nanosensors to Probe for Molecular Interactions in High Throughput
using NMR and MRI
J. M. PEREZ, L. Josephson, R.Weissleder, MGH-Harvard Medical School, Center for Molecular
Imaging Research, 139, 13th Street, 5404, Charlestown MA, jperez@hms.harvard.edu
Designing activatable imaging agents to sense molecular markers and molecular interactions
associated with disease would result in the development of more sensitive diagnostic agents and
the development of target-specific probes for in vivo molecular imaging applications. Toward
this goal, we have developed an assay to sense molecular targets using magnetic nanosensors and
nuclear magnetic resonance (NMR) in high-throughput. These magnetic nanosensors consists of
biocompatible magnetic nanoparticles capable of detecting a molecular target by changes in the
NMR signal of the solution as the nanoparticles self-assemble in the presence of the target. Using
four different types of molecular interactions (DNA-DNA, protein-protein, protein-small
molecule, and enzymatic reactions) as model systems, we have shown that these magnetic
nanosensors can detect these molecular interactions with high sensitivity and selectivity using
standard NMR or MRI instrumentation. The target-induced change in NMR signal is detectable
in turbid media or whole-cell lysate and is proportional to the amount of target present. The
assay is performed in solution, does not require isolation or purification of the samples and could
potentially be used for in vivo imaging. We will present data showing the utility of the technique
to detect molecular targets related to cancer, atherosclerosis, inflammation and infection. The
technology is versatile enough to sense the mRNA, protein and enzymatic activity of a molecular
target. Finally, we have been able to detect specific viruses in solution, allowing for sensitive and
selective detection of low numbers of viral particles.
6-25
Selectively Moving Biopolymers Through Functionalized Nanotube Membranes
PUNIT KOHLI1, Charles R. Martin2, 1Department of Chemistry and Biochemistry, Southern
Illinois University, Carbondale, IL, 2Department of Chemistry and Center for Research at the
Bio/Nano Interface, University of Florida, Gainesville, FL, pkohli@chem.siu.edu,
crmartin@chem.ufl.edu
The ability to regulate transport across cellular boundaries is essential to the cell’s existence as
an open system. There is a steady traffic of ions, molecules, polymers and other species across
the plasma membrane. For example, sugars, amino acids, and other nutrients enter the cell;
waste products of metabolism leave. The cell takes in oxygen for cellular respiration and expels
carbon dioxide. It also regulates its concentrations of inorganic ions, such as Na+, K+, Ca2+, and
Cl-, by shuttling them one way or the other across the plasma membrane. Mother Nature has
created natural channels that are highly selective; they allow certain molecules and ions to pass
more easily than others or they reject them altogether. Understanding and mimicking of the
transport processes in cells is both challenging and rewarding from scientific and technological
points of views. We have prepared highly selective template-synthesized abiotic nanotube
membranes that can be used as model systems for better understanding of transport processes in
natural systems and also mimicking natural ion- and protein-channels. Our nanotubes have
diameters of the same order (1-100 nm) as those found in the natural protein channels. We have
designed these nanotube membranes to selectively recognize and transport nucleic acid
oligomers by modifying the inner surface of nanotubes with complementary nucleic acid
“transporters”. We show that these membranes can facilitate the transport of the complementary
DNA strands relative to DNA strands that are not complementary to the transporters. Under
optimum conditions, single-base mismatch transport selectivity is obtained. The second part of
my talk consists of fabrication of single-conical gold nanotube membranes functionalized with
DNA that mimics voltage-gated potassium channel. These DNA-immobilized single-conical
nanotubes exhibit “on-off” characteristics with external applied potential. These biofunctionalized nanotube membranes may find many potential applications in bioseparations, bioand chemical-sensing, drug-detoxifications, and other biomedical and biotechnological
applications.
6-26
Functionalizing FePt Nanoparticle Surfaces with Silane Chemistry
H. G. BAGARIA, D. E. Nikles, E. T. Ada, D. T. Johnson, Center for Materials for Information
Technology, Department of Chemical and Biological Engineering, Department of Chemistry and
The Central Analytical Facility. The University of Alabama, Tuscaloosa, AL,
djohnson@coe.eng.ua.edu
The preparation of monodisperse FePt nanoparticles was first reported by Sun et al. Though the
initial motivation for developing these particles was for ultra high density hard drives, these have
also found their way into biological applications owing to their high magnetization values. There
are reports in the literature where FePt has been used for cell separation and protein tagging
applications. The FePt prepared by the procedure developed by Sun et al. uses oleic acid and
oleyl amine ligands for stabilizing FePt in non-polar solvents. To make these particles suitable
for biological applications 1) they should be made hydrophilic and 2) they should have
functional groups on their surface to bind to biological entities. Towards this aim, our XPS
studies consistently show that a layer of iron oxide exists on the FePt nanoparticles. This
motivated us to study alkoxy silane based ligands as a means to introduce the desired
functionality. Studies with magnetite nanoparticles have shown the affinity of alkoxysilane
ligands for the iron oxide surface. The present work studies the binding of various silanes on the
FePt surface by conducting FTIR and XPS studies.
6-27
Biomaterials from Nanocolloids: Applications for Neurons
NICHOLAS A. KOTOV, Departments of Chemical Engineering, Biomedical Engineering and
Materials Science, University of Michigan, Ann Arbor, MI, kotov@umich.edu
The presentation will review the recent advances in the use of nanocolloids to add new
functionalities to biomaterials. Layer-by-layer assembly (LBL) affords preparation of ordered
layered structures from virtually unlimited palette of nanocolloids. Various functionalities of
nanocolloids afford preparation of targeted composites for evaluation of different neuronal
functions. Four examples will be discussed. Multilayers from TiO2 nanoshells afford selective
determination of neurotransmitters due to ion-sieving effect.
Strong, flexible and
electroconductive implants can be made from SWNT LBL multilayers. Stringent testing of
biocompatibility of these composites was undertaken and it was demonstrated that they are
suitable for long-term contacts with tissues. Stimulations of neurons through these films was
demonstrated. Nanoparticles with silver nanocolloids can be used to suppress inflammation
processes due to infection – one of the most important problems with implantable devices.
Photoactive multilayer from semiconductor particles were used to NG108*15 neuron precursor
cells on them. It was found that light adsorbed in the nanoparticle layers results in the electrical
excitation of the neurons making this system a functional analog of retina. Assemblies of claypolymer systems demonstrated exceptional toughness similar to that observed in bones. Layered
nanocomposites represent an exceptionally versatile tool for production of biomaterials with
novel applications derived from unique properties of nanostructured matter.
6-28
Strategies for the Design and Readout of Ultrahigh Density Immunodiagnostic Platforms
H.-Y. Park, J. Driskell, K. Kwarta, B. Yakes, J. Uhlenkamp, R. Millen, N. Pekas, J. Nordling, R.
J. Lipert, M. D. PORTER, Departments of Chemistry and Chemical Engineering, Institute for
Combinatorial Discovery, and Ames Laboratory-USDOE, Iowa State University, Ames IA,
mporter@porter1.ameslab.gov
The drive for early disease detection, the growing threat of bioterrorism, and a vast range of
challenges more generally in biotechnology has markedly amplified the demand for
ultrasensitive, high-speed diagnostic tests. This presentation describes efforts to develop
platforms and readout methodologies that potentially address demands in this arena through a
coupling of nanometric labeling with surface enhanced Raman spectroscopic, micromagnetic,
and scanning probe microscopic and readout concepts. Strategies will be described for both the
fabrication and read-out of chip-scale platforms that can be used with each novel readout
modality. Examples will focus on the use of protein arrays as platforms targeted for
immunoassays in early disease diagnosis and the rapid, ultralow level detection of cancer
markers and viral pathogens. Each example will also discuss challenges related to sensitivity
and nonspecific adsorption and to fluid manipulation at micrometer length scales.
6-29
Design of Multidentate Surface Ligands for Biocompatible Quantum Dots
H.T. Uyeda, K.M. Hanif, A.R. CLAPP, H. Mattoussi, Division of Optical Sciences, Code 5611,
U.S. Naval Research Laboratory, Washington, DC, hedimat@ccs.nrl.navy.mil
The utility of stable water-soluble luminescent quantum dots (QDs) has been demonstrated in
biosensing and cellular imaging applications. However, due to the nature of the inorganic QD
core, the native surface properties limit their compatibility with aqueous environments. We have
designed a series of organic poly-ethylene glycol based surface capping ligands that allow for
QD manipulation in aqueous media over a wide pH range. We utilized readily available thioctic
acid and various oligo- and poly-ethylene glycols (PEG) in simple esterification schemes,
followed by reduction of the dithiolane to produce multi-gram quantities of capping ligand
(DHLA-PEG). This strategy was further applied to prepare biotin-terminated DHLA-PEG
capping ligands. To form water-soluble QD assemblies, native trioctylphosphine and
trioctylphosphine oxide (TOP/TOPO) capped nanocrystals were mixed with an excess of the
desired surface ligand and incubated for a few hours to displace the TOP/TOPO molecules. This
permitted us to obtain homogeneous dispersions of QDs that were stable over wide pH ranges
and extended periods of time. We also prepared QDs having mixed surfaces of dihydrolipoic
acid (DHLA) and DHLA-PEG (or DHLA-PEG-biotin). This design and conjugation strategy
may facilitate the development of a new generation of QD-bioconjugates for use in a variety of
biological applications.
6-30
Nucleic Acid Sequence and Protein Identification using Gold Nanoparticle Probes and the
VerigeneTM System
J. J. STORHOFF, Y. P. Bao, S. S. Marla, M. Huber, T-F Wei, A.D. Lucas, S. Hagenow, V.
Garimella, W. Buckingham, T. Patno, W. Cork and U.R. Müller, Nanosphere, Inc., Department
of Applied Science, 4088 Commercial Avenue, Northbrook, IL, jstorhoff@nanosphere.us
Nucleic acid sequence identification is widely used for detection of viruses, bacterial pathogens,
and genetic disease predispositions. Most current detection platforms require nucleic acid target
amplification necessitating complex assay procedures and instrumentation. Nanosphere, Inc. has
developed a novel gold nanoparticle probe-based platform to detect nucleic acids without target
amplification. Two key factors have enabled this transformation. First, gold nanoparticles
coated with oligonucleotides exhibit sharper melting transitions which increase sequence
specificity in detection assays. Second, simple optical instrumentation that detects scattered light
from gold nanoparticle probes provides a 1000 fold improvement in detection sensitivity over
current fluorescence scanners. The combined sensitivity and specificity of this detection
platform has enabled the multiplex detection of SNPs in total human genomic DNA, as well as
PCR-less identification of bacterial pathogens. The sensitivity of this platform is enhanced by
capturing the nucleic acid target (or protein target) with a magnetic bead and labeling the
complex with a gold nanoparticle functionalized with barcode DNA sequences. The barcode
DNA sequences are used to identify the target sequence present and to amplify the signal since a
single nanoparticle can carry thousands of barcodes. Following magnetic separation, the barcode
DNA sequences are released and detected using the VerigeneTM System.
6-31
Surface Functionalization of Semiconductor Quantum Dots for Applications in Biological
Sensing
MEGAN A. HAHN, Todd D. Krauss1, Joel S. Tabb2, 1Department of Chemistry, University of
Rochester, Rochester, NY, 2Agave BioSystems, Ithaca, NY, mahn@mail.rochester.edu
Having diameters of only a few nanometers, colloidal CdSe semiconductor quantum dots (QDs)
are highly emissive, spherical, inorganic particles that exhibit size-tunable physical properties
due to the effects of quantum confinement. Typically, these materials are synthesized with
relatively inert hydrocarbon surface-groups that must first be modified if they are to be
compatible with biological systems. To that end, a variety of strategies have been established to
make these hydrophobic surfaces of CdSe QDs applicable for use in biology. We have
demonstrated that CdSe/ZnS core/shell QDs functionalized with streptavidin bind specifically to
pathogenic Escherichia coli O157:H7 cells labeled with biotinylated antibodies. Using
fluorescence microscopy of individual bacterial cells and standard fluorimetry of bacterial cell
solutions, we will also present results comparing E. coli O157:H7 cells labeled with QDs to cells
similarly labeled with a standard dye, fluorescein isothiocyanate (FITC). The particular
biochemical interactions and surface functionalization incorporated in these methods can easily
be generalized to allow for the rapid and selective detection of other common pathogens.
6-32
Combining Gold Nanoparticles with the Quartz Crystal Microbalance to Improve the
Sensitivity of DNA Detection
T. LIU, J. A. Tang, L. Jiang, Key Laboratory of Colloid and Interface, Center of Molecular
Sciences, Institute of Chemistry, Chinese Academy of Sciences, Zhong Guan Cun, Beijing,
ROC, taoliu@iccas.ac.cn, leotao1974@yahoo.com
Investigation indicates that the appearance of the malignant tumor is highly correlative with the
DNA mutation. It has become an important topic of the cancer study to detect the gene mutation
and look for the relation between mutation and pathological change at the molecular level. Rapid
detection for trace gene mutation can provide basic data for diagnose disease. Therefore, looking
for a rapid and simple method used for detecting trace mutation is important and pressing. QCM
is a simple, rapid and real-time measurement of DNA binding and hybridization at the subnanogram level. The nanogold particle has many special properties, for example high density,
simple operation, and easy size-controlled. Combining these two techniques, i. e., nanoparticle
modification of QCM surface and the application of gold narnoparticle amplifier, we improved
the detection limit of DNA. This method makes it possible to detect single base mutation less
than 10-16 mol / L.
6-33
Effects of Surfactants and Surface Charge on the Performance of Latex
Immunoagglutination Assays in Vitro and in a Microfluidic Device
LONNIE J. LUCAS, Jin Hee Han, Jeong-Yeol Yoon, Department of Agricultural and
Biosystems Engineering, The University of Arizona, Tucson, AZ, jyyoon@email.arizona.edu
The latex immunoagglutination assay is a relatively easy, rapid technique for detecting
biomolecules. However, improvements in reliability and sensitivity are still required. The main
issues involve colloidal stability of the antibody-latex complex and non-specific binding of
antigens. To address these issues, we investigated the influence of surfactants and surface charge
of particles toward its performance. To examine the effects of surfactants, we used the ionic SDS
and the non-ionic Tween 80 with submicron polystyrene (PS) particles. To examine the effects
of surface charge we compared plain PS with highly carboxylated PS. All latex particles were
conjugated with anti-mouse IgG (developed in goat). The antigen was mouse IgG (positive
control) or rabbit IgG (negative control). Immunoagglutination was monitored turbidimetrically
using a spectrophotometer. We found that plain PS with either no surfactant or ionic SDS
produced many false-positives and false-negatives. Results were substantially improved when
non-ionic Tween 80 was mixed with plain PS. When carboxylated PS was used with no
surfactant, the results were also very accurate and reliable. We also demonstrated these effects in
a Y-channel microfluidic device. Immunoagglutination occurred faster and in greater quantity
near the Y-junction, when Tween 80 surfactant was used rather than no surfactant.
7-01
Synthesis and Processing of Nanoparticles for Bioengineering Applications
JACKIE Y.YING, Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The
Nanos, #04-01, Singapore, jyying@ibn.a-star.edu.sg
Nanostructured materials are of interest for a variety of applications. This talk describes the
synthesis and properties of nanostructured materials that are made up of crystallites or particles
of ~10 nm. They may be generated by various physical and chemical approaches with ultrahigh
surface reactivity. Through controlled synthesis in reverse microemulsions, my laboratory has
achieved polymeric nanoparticles for the glucose-sensitive delivery of insulin. These stimuliresponsive materials allow for the appropriate insulin delivery to diabetic patients only when
their blood sugar levels are high, without the need for external blood sugar monitoring. We have
also developed apatite-polymer nanocomposite particles for the sustained, zero-order delivery of
protein therapeutics. By adsorbing valuable bone morphogenetic proteins on carbonated apatite
nanocrystals that were then encapsulated within biodegradable polymeric microparticles, we are
able to achieve controlled release of this growth factor for the bone healing process over an
extended period of time.
Lastly, we have generated fluorescent semiconductor quantum dots for bioimaging and
biolabeling applications. These nanoparticles were surface modified to provide for high colloidal
stability, efficient fluorescence, low cytotoxicity and excellent water solubility. They were
biocompatible and biofunctionalized for target-specific recognition, and could be used for
biosensing and targeted drug delivery applications.
7-02
Nanoparticles as Detection Labels for Bioaffinity Assays in Point of Care Testing
MICHAEL PUGIA, Bayer HealthCare LLC, Diagnostics Division, 1884 Miles Avenue, Elkhart
IN
Nano-particles are commonly used in Point-of-Care Testing (POCT) as detection labels. These
small low cost clinical analyzers use particles as detection labels.Optical signals generated by
latex agglutination, colored latex particles, and colloidal gold commonly provide little
interference and picomolar detection limits (10-12 mol/L). Miniaturization to nL specimen
volumes and lower analyte concentrations resulting from proteomics discoveries are challenging
these limits. Flourimetric, luminescence and enzyme-linked particles offer more sensitivity at the
expense of complexity. Simple nano-particle electrochemical methods have recently shown
sensitivity to single molecule limits.
Nano-particles also impact recognition and separation steps in POCT.
Immunological
recognition of antigens with antibodies greatly enabled POCT. Particles attached to antibodies
are separated when antibodies reacts to antigens captured on solid phases. Particle variations
impact the ability of recognition components to separate after binding the target substance. The
CLINITEK Status analyzer demonstrates the impact of particles on chromatography separations
using incubation, capture and separation zones. Immunoassay of a new maker for inflammation
demonstrates the complexity of recognition components. Another fluidic approach is shown in
the HbA1c immunoassay on the DCA 2000+ analyzer, while examples of micro-fluidic chips
show the impact of future miniaturized on bio-affinity separations in POCT.
7-03
Cellular Probes Using Amplified Light Scattering
O. Siiman, S. LEDIS Advanced Technology Center, Beckman Coulter, Inc., Miami, FL,
olavi.siiman@coulter.com
Silver/gold nanoparticle-aminodextran (Amdex)-coated polystyrene (PS) beads offer their use
either as elastic or inelastic light scattering probes for diagnostic biological assays. Amplified
Mie scattering from CD4/CD8 antibody conjugates of these beads has allowed their use in
enumerating the targeted white blood cells in whole blood by flow cytometry. Recent
observations of SERS (surface-enhanced Raman scattering) from the same beads hold the
promise of using Raman in similar diagnostic tests. Citrate/Amdex SERS bands were detected
from beads either as singlets or small clusters. However, citrate on individual silver
nanoparticles or on gold nanoparticle-Amdex-PS beads were not detected with 633nm excitation.
SERS of dyes such as rhodamine 6G were readily observed on individual silver particles or on
gold beads.
Three distinct modes of citrate/aminodextran binding to the silver nanoparticle-Amdex-PS beads
were characterized: (1) exchangeable citrate bound through one or more carboxylate group(s)--citrate could be washed away with H2O or D2O; displaced by successively greater concentrations
of R6G; or squeezed out mechanically by applying the pressure of a second coverslip on top of a
droplet of bead suspension; (2) non-exchangeable citrate/Amdex bound via an alkoxide of a
deprotonated alcohol of citrate/Amdex; (3) non-exchangeable citrate/Amdex bound via
carboxylate group(s) but with H/D exchangeable alcohol hydrogen atom. The 3 modes of
binding provide flexibility in selecting intrinsic, fixed SERS probes as well as the opportunity to
add selected, variable probes to the beads for multiple diagnostic targets. Such probes could be
used in micro-Raman imaging and, potentially, in a Raman-activated flow cytometer.
7-04
Determination of Dissolution Rates of Colloidal Dispersion Prepared From Poorly Water
Soluble Drugs Using a Light Scattering Technique
N. P. RYDE, J. D. Pruitt, Elan NanoSystems, King of Prussia, PA
Classic theory predicts that the diffusion limited rate of dissolution of fine particles increases as
the particle size becomes smaller. This has been demonstrated in numerous pharmaceutical
formulations incorporating NanoCrystal technology. The threshold where the rate limiting
transport step changes from dissolution limited to permeation limited oral absorption defines a
size below which no further kinetic benefits to absorption are theoretically observed.
Pharmacokinetic results suggest a smaller particle size threshold than classic theory (NoyesWhitney).
A light scattering method was used to determine the in-vitro rate of dissolution for drug
dispersions in the absence of solubilizing agents. The experimental results were compared with
two different theories, a classic Noyes-Whitney and a modified Noyes-Whitney type equation
constrained by a surface mass transfer rate. The new theory treats the surface mass transfer step
and diffusion step as two consecutive reactions. The overall dependence on particle size is 1/r for
very small particles and 1/r 2 for larger particles (both limits assuming a time dependent
boundary layer h = r). Experimental results revealed dissolution rates much smaller than ones
predicted from classic theory. The corresponding surface mass transfer coefficient could be
extracted from such experiments.
7-05
PFG-NMR Investigation of Liposome Systems Containing Hydrotrope
FADWA ODEH, Nicole Heldt, Michele Gauger, Gregory Slack§, Yuzhuo Li*, Department of
Chemistry, Clarkson University, Potsdam, NY, § Wyeth Aryst, Rouses Point, NY
Particle size is crucially important in determining the usefulness of a liposome system. This is
particularly true for drug delivery applications. Until now, the particle size of a liposome is
typically determined using a light scattering method. Although the NMR pulsed field gradient
(PFG) experiments are known to yield self-diffusion coefficient for micelles and other particulate
matters, the application of this technique to vesicle systems has been limited due to the rigid
nature of the lipid bilayer which usually does not give well-defined NMR signals for PFG
experiments. This study shows that the polyethylene oxide chains on a pegylated lipid could
serve as an excellent tracer to measure the self-diffusion coefficient via PFG method. In
addition, liposomes containing a hydrotrope also give adequate signal from the lipid for PFG
experiments due to the increased flexibility of the lipid molecules. In addition to particle size,
PFG-NMR is also used to determine the extent of association of a hydrotrope with the liposome
bilayer.
7-06
Fabrication of Supraparticles, Janus Microparticles and Microlens Arrays by a Gel
Trapping Technique
VESSELIN N. PAUNOV, Olivier J. Cayre, Physical Chemistry Surfactant & Colloid Group,
Department of Chemistry, University of Hull, Hull, United Kingdom, V.N.Paunov@hull.ac.uk
Particles with asymmetric shapes that can be used to make crystals with novel optical properties
have attracted much attention in recent years. We have shown that the Gel Trapping Technique
(GTT) can be used to asymmetrically coat colloidal monolayers creating so-called 'Janus'
particles, after the two-faced Roman god of doors. Partially embedded monolayers of
monodisperse polystyrene microparticles in polydimethylsiloxane (PDMS) were used to coat the
exposed particle surface with gold, resulting in particles with two 'faces'. The technique is
relatively simple and could easily be used to make a variety of Janus particles. Monodisperse
polystyrene microparticles are spread at a water-oil interface and super long range repulsion
between particles adsorbed at the interface leads to a near perfect hexagonal lattice. The water
contains the gelling polysaccharide gellan which, on cooling, forms a gel that traps the
monolayer and the oil layer may then be removed without disturbing the particles. Pouring liquid
PDMS over the gel followed by curing leads to the formation of a partially embedded monolayer
trapped within the PDMS resin which can be peeled away from the gel. To make the Janus
particles the trapped polystyrene particles were 'half-coated' with gold. Use of particles of
different contact angles allows the creation of monolayers with varying degrees of entrapment of
the polystyrene particles within the gel and thus to different degrees of coverage on their surface.
At certain conditions we have successfully molded the particle monolayer together with its
gelled meniscus around the particles which produced 'flying saucer particles' where the
polystyrene particles are surrounded by a ring of gellan.
Stretching the PDMS releases the trapped particles and the PDMS films produced, with an
ordered array of microholes, could have interesting potential applications as filters or
antireflective coatings. By further replicating the microhole array with a photopolymer we
produced hexagonally ordered microlens arrays where the lattice constant is fixed by the amount
of particles spread at the initial liquid surface.
We also used the same Gel Trapping Technique as a novel method for determining the contact
angle of particles adsorbed at air-water and oil-water interfaces. The trapped particles have been
imaged on the surface of the PDMS replica with SEM. The particles position with respect to the
air-water interface or the oil-water interface has been determined from the SEM images of the
PDMS replica which gives information for the particle contact angle at the liquid interface.
Particle samples of different size and surface chemistry have been examined. We present results
for the particles contact angles at air-water and decane-water interface obtained for sulfate latex
particles, hydrophobized silica particles, gold particles and polymer microrods.
7-07
Bone Tissue Engineering: Towards a Better Understanding of Interfacial Biology
D. LICKORISH, Bone Interface Group, Institute for Biomaterials and Biomedical Engineering,
University of Toronto, 170 College Street, Toronto, ON, Canada, d.lickorish@utoronto.ca
Approximately 1 million bone grafts are performed annually in the USA. Current methods of
grafting, such as autograft and allograft, are subject to significant limitations. These limitations
are driving the development of a range of ‘off the shelf’ materials that can expedite osseous
healing. Our strategy has been to develop a three phase macroporous co-polymer of polylactideco-glycolide and calcium phosphate that can function as a temporary trellis to take advantage of
the appositional nature of bone formation. Using data garnered from in-vitro and in-vivo
experiments, the iterative development of this scaffold, in response to both material and
biological design criteria, will be discussed. In addition to developing a scaffold material suitable
for bone tissue engineering, the notion of exogenous delivery of mesenchymal progenitor cells to
the repair site to accelerate bony repair is attractive. Our recent characterization of an exciting
and uncontroversial source of these cells, the human umbilical cord perivascular tissue, will be
described, as will the challenges remaining to clinical realization of cell based therapy for bone
tissue engineering.
7-08
Surface Modification of Mineral Fillers for Dental Composites and Acrylic Bone Cement
O.SHAFRANSKA1, A.Kokott1, V.Tokarev2, S.Voronov, G.Ziegler1, 1Friedrich-Baur Research
Institute for Biomaterials, Bayreuth University, Ludwig-Thoma-Str.,36c, 95447, Bayreuth,
Germany, 2National University “Lviv Polytechnic”, Lviv, Ukraine, olena.shafranska@fbibiomaterialien.de
The surface modification of mineral fillers for acrylic composites is very promising in bone
cement and dental applications. Using surface modified mineral fillers, such as silica and
zirconia, in polymer composite materials allowed us to improve substantially the filler – matrix
adhesion and the mechanical properties of the composite. In the present work the surface of the
mineral filler was modified by adsorption of peroxide copolymer (5-methyl-5-tert-butylperoxy2-hexen-3-in and maleic anhydride) as well as by the covalent immobilization of methacryloxyand styryl groups due to interaction with styrylethyl-trimethoxysilane and methacryloxypropyl
trimethoxysilane. The peroxide groups were used to initiate the graft polymerization of acrylic
monomers. Methacryloxy- and styryl groups interacted with (macro)radicals and formed the
covalently attached polymer layers.
The efficiency of the grafting was studied on the model smooth SiO2 substrate. The amount of
the grafted polymer layers was measured by ellipsometry. We found that the most efficient
grafting was approached for the poly(methyl methacrylate) on the surface modified by the
7-09
Amphiphilic Core-Shell Nanoparticles with Poly(ethylenimine) Shells as Potential Gene
Delivery Carriers
Junmin Zhu,1 Angie Tang, 1 Lai Pang Law,1 Min Feng1, Kin Man Ho1, Daniel K. L. Lee1, Frank
W. Harris,2 PEI LI, Department of Applied Biology and Chemical Technology, and Open
Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and
Synthesis, The Hong Kong Polytechnic University, Hung Hom, Kowloon, P. R. China, 2Maurice
Morton Institute of Polymer Science, University of Akron, Akron, OH, bcpeili@polyu.edu.hk
Spherical, well-defined core-shell nanoparticles that consist of poly(methyl methacrylate)
(PMMA) cores and branched poly(ethylenimine) shells (PEI) were synthesized in the absence of
surfactant in aqueous. The PMMA-PEI core-shell nanoparticles were between 130 to170 nm in
diameters, and displayed zeta-potentials near +40 mV. Plasmid DNA (pDNA) was able to
complex onto the nanoparticles, and average diameter of the complexed particles was
approximately 120 nm and highly monodispersed. The complexing ability of the nanoparticles
was strongly dependent on the molecular weight of the PEI and the thickness of the PEI shells.
The stability of the complexes was influenced by the loading ratio of the pDNA and the
nanoparticles. The condensed pDNA in the complexes was significantly protected from
enzymatic degradation by DNase I. Cytotoxity studies suggested that the PMMA-PEI (25 kDa)
core-shell nanoparticles were three times less toxic than the branched PEI (25 kDa). Their
transfection efficiencies were also significantly higher. Investigation of the intracellular behavior
of the FITC-labeled DNA/nanoparticles indicated that the PMMA-PEI nanoparticles were
effective carriers to deliver the DNA into cells by endocytosis and release it into the cytosol.
Thus, the PEI-based core-shell nanoparticles show considerable potential as carriers for gene
delivery.
7-10
Microencapsulation of Pharmaceuticals into Biodegradable Colloids Using Supercritical
Carbon Dioxide
H. Liu, N. Finn, M.Z.YATES, Department of Chemical Engineering and Laboratory for Laser
Energetics, University of Rochester, Rochester, NY, myates@che.rochester.edu
The microencapsulation of pharmaceuticals into biodegradable polymer colloids can be utilized
for controlled, extended, and targeted drug delivery. We have developed a solvent-free
alternative microencapsulation process that utilizes liquid or supercritical carbon dioxide in place
of organic solvents. Here we demonstrate that compressed carbon dioxide may be used to
facilitate the transport of pharmaceuticals into aqueous biodegradable polymer colloids. The
“nano-precipitation” method was used to form stable aqueous colloids of several types of
biodegradable polymers including poly(lactic acid), poly(lactide-co-glycolide), and poly(lactic
acid)-block-poly(ethylene glycol). In all cases, particle formation conditions yield particles less
than 200 nm in diameter. Liquid or supercritical carbon dioxide was emulsified into the aqueous
biodegradable latex in the presence of a lipophillic drug such as indomethacin and progesterone.
The carbon dioxide plasticizes the polymers and greatly enhances the transport of drug into the
particles. The carbon dioxide process has also been coupled with traditional microencapsulation
approaches to minimize solvent usage and to extract residual solvent from polymers.
7-11
Development of a Three-Dimensional Magnetic Navigation and Magnetically Targeted
Drug Delivery System
S.TAKEDA, Fumihito Mishima, Shigehiro Nishijima, Department of Sustainable Energy and
Environmental Engineering, Graduate School of Engineering, Osaka University, Japan,
stakeda@nucl.eng.osaka-u.ac.jp
One of the key problems associated with drug administration is the difficulty to target specific
areas or sites in the body, like cancerous tumors. Typically in these cases, exceedingly large
doses of a drug are needed to ensure that some of the drug reaches a specific site, which
unavoidably impose substantial toxic side effects at non-targeted organs. In the present study,
development of a three dimensional magnetic navigation and magnetically targeted drug delivery
system was tried in order to deliver the drug to target specific areas in the body by utilizing
magnetic particles and strong magnet. Earnshaw’s theorem states that there is no stable and static
configuration of levitating ferromagnetic particle by a combination of a fixed magnetic field and
gravitational force. However, the magnetic particle could be levitated in a limited area using by
the feedback system. In this paper, designing of the electromagnet was tried to control the
movement of particles through the experimental and the computer simulation. The surface
modification of the magnetic particles was also discussed in order to control the interaction
between the particles and wall of the blood cell.
7-12
Reversible Assembly/Disassembly between Two Different Micelle Morphologies Comprised
of Cyclodextrin and Ferrocene/Ferrocenium Derivatized Surfactants
Kejun Cheng,YanMei Lan, YAN-YEUNG LUK, Department of Chemistry; Department of
Biomedical & Chemical Engineering, Syracuse University, Syracuse, NY, yluk@syr.edu
We report the reversible switching between two different micelle morphologies via the
disassembly and re-assembly of redox-active surfactants by electrochemical means. The redoxactive surfactant is comprised of an aliphatic chain tethered to a ferrocene group covalently
caged in the annular void of beta-cyclodextrin (bCD). While beta-cyclodextrin by itself has a
water solubility too low for consideration as a hydrophilic head group, our covalent modification
renders this molecule amphiphilic, and thus surface active. Using bCD as the hydrophilic head
group, this surfactant is bio-friendly in that protein denaturation is minimal or non-existent.
Employing a wide range of characterization techniques such as 2-dimensional NMR
spectroscopy, circular dichroism and electrochemistry, we demonstrated that accompanying the
oxidation of ferrocene to ferrocenium, the surfactant undergoes a large conformational change
that results in the disassembly of the micelle formed and re-assembly of a new micelle
morphology. We will discuss/present its potential applications in sequestering membrane
proteins and controlled drug release.
7-13
Smart Polymer Core-Shell Nanoparticles for Targeted Drug Delivery
Y. Y. YANG, S. Q. Liu, L. H. Liu, R. Powell, Y. WangInstitute of Bioengineering and
Nanotechnology, 31 Biopolis Way, The Nanos, Singapore, yyyang@ibn.a-star.edu.sg
Drug delivery is as important as the development of new drug entities. The main goal of drug
delivery is to transport drugs to diseased sites using a therapeutic dosage. A number of
nanocarriers have been proposed based on natural and synthetic materials to achieve such a goal.
However, the method of delivering drugs to specific cells and cell compartments remains a
challenge. The aim of our study is to develop polymer core-shell nanoparticles for transporting
drugs/genes to specific tissues, thereby alleviating or eliminating the side effects associated with
the use of conventional delivery systems and improving the efficacy of drug or gene therapy.
In this talk, pH-triggered temperature-sensitive core-shell nanoparticles will be introduced. The
structure of these nanoparticles is stable in the normal physiological environment (pH 7.4), but
deforms and releases the enclosed drug molecules in an acidic environment. A signal that
recognizes tumor cells is conjugated to the shell of the nanoparticles, making them capable of
targeting a drug to tumor cells and then releasing it intracellularly for more efficient and safer
cancer therapy. Cellular uptake of the nanoparticles loaded with doxorubicin is higher than free
doxorubicin because folate-receptor mediated cell uptake is more specific. Therefore, the
nanoparticles loaded with doxorubicin kill cancer cells and suppress cancer growth more
efficiently as compared to free doxorubicin.
7-14
Labled Block Copolymer Micelles in the Study of Cellular Internalization
P. Lim-Soo1, S. Sidorov2, R. Savic3, L. Bronstein2, D. Maysinger3, A. EISENBERG4,
1
Department of Pharmacy, University of Toronto, Toronto, ON, Canada, 2Nesmeyanov Institute,
Moscow, Russian Federation, 3Department of Pharmacology and Therapeutics, McGill
University, Montreal, QC, Canada, 4Department of Chemistry, McGill University, Montreal, QC,
Canada
The Possibilty of developing drug delivery systems for specific subcellular organelles has
triggered an interest in the subcellular localization of specific delivery vehicles such as block
copolymer (BC) micelles. Two micellar systems are described which can be used for this
purpose at different levels of resolution. One involves a micelle consisting of a hydrophilic poly
(ethylene oxide) corona surrounding a hydrophobic core, which envelops an electron dense gold
prarticle. The internalization can be followed by isolating and sectioning, the cells at specific
times after exposure, and investigating them by electron microscopy. While the technique is
somewhat labor-intensive, the resolution is excellent, and limited essentially by the size of the
gold particle. The other micellar system is based on the attachment of a flurescent label to the
hydrophobic chains, e.g. in micelles consisting of a diblock copolymer of polycaprolactone and
poly (ethylene oxide). Localization is now studied by confocal fluorescent microscopy, and can
be aided by the labeling, with a different dye, of specific subcellular organelles. Co-localization
is evidenced by color superposition. The technique is simpler than electron microscopy, but the
resolution is typical of optical microscopy. The two micellar systems thus constitute
complementary methods of studying subcellular localization by techniques with very different
resolution capabilities, giving information over regions of very different sizes.
7-15
Synergy of Drug and Gene Delivery Using Cationic Polymer Core-Shell Nanoparticles
Y. WANG, S. J. Gao, Y. Y. Yang Institute of Bioengineering and Nanotechnology, 31 Biopolis
Way, The Nanos, #04-01, Singapore, ywang@ibn.a-star.edu.sg
In cancer therapy, two or three agents are often combined to achieve a synergic effect for better
killing of cancer cells. For example, p53-encoded gene can be combined with cisplatin to achieve
more promising therapeutic results. Co-delivery of cyclosporin A and paclitaxel can improve
gene transfection efficiency. To achieve the synergy of drug and gene therapies, we believe that
it is necessary to deliver the drug and gene to the same cells. However, up to date, no single
nanosized carrier has been reported to deliver a drug and gene simultaneously. In this study,
unique polymer core-shell nanoparticles are developed, which can carry a drug and gene
simultaneously. For examples, expression levels of luciferase and eGFP genes in 4T1 mouse
breast cancer cells are increased by 10 times using the paclitaxel-loaded nanoparticles as
compared to the blank nanoparticles. The in vivo studies are conducted in mice bearing
subcutaneous 4T1 tumors. Luciferase activity in the tumors, which is transfected by the
paclitaxel-loaded nanoparticles/luciferase-encoded plasmid complexes, is 10 times higher when
compared to the blank nanoparticles/luciferase-encoded plasmid complexes. Moreover,
cyclosporin A has also proved to enhance luciferase gene expression in MB-31-MA cells (a drug
resistant cell line). In conclusion, these unique cationic core-shell nanoparticles would provide a
promising carrier for co-delivery of drugs and genes.
7-16
Controlled Release of Plasmid DNA from Gold Nanorods Modified with
Phosphatidylcholine Induced by Pulsed Near-Infrared Light
H. Takahashi, Y. Niidome, T. NIIDOME, S. Yamada, Department of Materials Physics and
Chemistry, Graduate School of Engineering, Kyushu University, Hakozaki 6-10-1, Higashi-ku,
Fukuoka, Japan, thirotcm@mbox.nc.kyushu-u.ac.jp
Gold nanorods (NRs) are rod-like nanoparticles that have unique optical properties depending on
their shape. In order to use NRs for biochemical applications, we have first partially modified
them with phosphatidylcholine (PC). Partial modification of NRs with PC has been successful
by extraction with chloroform containing PC. The resultant PC-modified NRs (PC-NRs) could
form complexes with plasmid DNA by electrostatic interactions, denoted as PC-NR/DNA.
Pulsed laser irradiation of NRs induces shape changes into spherical nanoparticles. Irradiation of
pulsed 1064-nm laser light (250 mJ/pulse, 2 min) to PC-NR/DNA complexes induced shape
changes of PC-NRs and at the same time plasmid DNA were released from the complexes as
confirmed from gel electrophoresis. Thus, it is clear that the shape changes of PC-NRs trigger
the release of DNA from the complexes. It was also found that the plasmid DNA was released
without any damage by laser irradiation. Thus, the near-IR laser irradiation onto the PCNR/DNA complexes has realized the selective release of the plasmid DNA without appreciable
structural changes.
7-17
Towards the Development of HFA-based pMDIs for the Delivery of Hydrophilic Drugs:
Combined Chemical Force Microscopy, In-Situ High-Pressure Tensiometry and Atomistic
Computer Simulations
R. P. S. Peguin, P. Selvam, L. Wu, S. R. P. DA ROCHA, Department of Chemical Engineering
and Materials Science, Wayne State University, Detroit, MI, sdr@eng.wayne.edu
Aerosol inhalation therapy is an alternative to oral and parenteral approaches for the delivery of
systemically active drugs. Pressurized metered dose inhalers (pMDIs) are the least expensive
aerosol therapy devices available, and have been suggested as potential candidates for the
delivery of pharmaceutically relevant biomolecules. However, there have been several
challenges in the design of pMDIs as CFCs are being replaced with more environmentally
friendly alternatives, such as hydrofluoroalkanes (HFAs). In spite of the fact that the operation
of pMDIs with HFAs is similar to those with CFCs, previous formulations are not compatible
due to the significantly different properties between these two classes of fluids. Lack of
fundamental knowledge on the interfacial properties of volatile propellant mixtures is preventing
us from extending the applicability of reliable and simple formulations such as pMDIs for the
delivery of polar drugs. Thermodynamic and microstructural properties of the neat and
surfactant-modified HFA|Water interface were obtained using a combined experimental and
computational approach, including chemical force microscopy, in-situ high-pressure tensiometry
and atomistic computer simulations. These studies are relevant not only for the development of
aqueous reverse microemulsion-based pMDI formulations, but all HFA-related pMDIs where
amphiphilic excipients are generally required.
7-18
Hydrogen-bonded Self-assembled Films and Capsules of Thermoresponsive Polymers
E. KHARLAMPIEVA, V.Kozlovskaya, S. A. Sukhishvili, Department of Chemistry and
Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, ekharlam@stevens.edu
Temperature responsive polymers, poly(vinyl methyl ether) (PVME) and poly(N-vinyl
caprolactam) (PVCL), were assembled in alternation with polymethacrylic acid (PMAA) at
acidic pH via hydrogen bonding using a layer-by-layer technique. The construction of
PVME/PMAA and PVC/PMAA films and capsules was confirmed by ellipsometry, in situ ATRFTIR, and Fluorescence Optical Microscopy. The film thickness and pH-stability were shown to
be highly dependent on hydrogen bond strength and the critical ionization of PMAA within the
films. The permeability of Thymol Blue dye through films deposited onto alumina supporting
membranes was investigated at acidic pH as a function of temperature and revealed striking
differences between the two polymer systems. While PVCL/PMAA films did not show any
significant effect of temperature on dye permeability in the range of temperatures from 20 to
40oC, permeation through PVME/PMAA films showed drastic increase at temperatures higher
than 32̊C. We explain the observed difference by stronger hydrogen bonding between PVCL and
PMAA components of the film, which resulted in suppression of film temperature response.
However, weakly bound PVME/PMAA systems allowed dehydration of PVME chains at
temperatures above its LCST which caused an increase in dye permeability.
7-19
Development of Redox-Active Surfaces and Micelles for Biocompatible Systems: Caging
Ferrocene in Cyclic Oligosaccharides
YAN-MEI LAN, Kejun Cheng, Yan-Yeung Luk, Department of Chemistry; Department of
Biomedical & Chemical Engineering, Syracuse University, Syracuse, NY, yluk@syr.edu
We report the development of a redox-active surface that is stable under biological conditions.
Our system is based on self-assembled monolayers (SAMs) that present a molecularly caged
ferrocene. The oxidized form of ferrocene – ferrocenium ion – is not stable in the present of
small anions as simple as chloride. Caging the ferrocenium ion in a cyclic oligosaccharide – cyclodextrin (CD) renders it stable in biological buffers such as cell culture medium, which
contain large concentration of chlorides. We also present a novel micelle system based on the
same strategy that covalently cages ferrocene in the annular void of CD. Using
OL98\f"Symbol"\s12CD as the hydrophilic head group, this surfactant is bio-friendly in that
protein denaturation is minimal or non-existent. Employing a wide range of characterization
techniques such as 2-dimensional NMR spectroscopy, circular dichroism and electrochemistry,
we demonstrate that accompanying the oxidation of ferrocene to ferrocenium, the surfactant
undergoes a large conformational change that results in the disassembly of the micelle formed
and re-assembly of a new micelle morphology. We will present its potential application in
sequestering membrane proteins and controlled drug release.
7-20
Self-Assembly of Nanoporous Silica Shapes: Synthesis, Morphogenesis, and Applications
YA.YU. KIEVSKY, I. Yu. Sokolov, Center for Advanced Materials Processing, Department of
Physics and Department of Chemistry, Clarkson University, Potsdam, NY,
kievskyy@clarkson.edu
We study the process of self-assembly of nano(meso)porous silica particles via surfactant
templating. Process of formation of the mesoporous silica includes growth of the liquid
crystalline template and solidification of this template via polymerization of silica precursor.
Material obtained as a result of such synthesis (MCM-41) features highly uniform porosity, a
large variety of shapes and their sizes. To control the assembly of the desired shapes, we study
their morphogenesis. New conditions of self-assembly are found to form monoshaped
nanoporous fibers. Recently suggested Origami-type mechanism for synthesizing a rich family of
nanoporous silica shapes (cones, tubes, and hollow helixes) is examined. Shape details and their
evolution are analyzed by means of XRD, SEM, TEM, AFM, and optical microscopy techniques.
The shapes can possibly serve as templates for various electronic and optical applications.
Nanoporous shapes are the prospective hosts for lasing dyes (sealing laser dye molecules inside
the silica pores saves them from oxidation and prevents their dimerization). Diffusion from the
nanoporous shapes can be used for a control drug release. Another application of mesoporous
silica is the coating of optical fibers by uniform low refractive index film with a good adhesion –
a possible host for laser dyes or quantum dots.
7-21
Particle Engineering Technologies for Enhancing Dissolution and Bioavailability
MICHAEL J. JOHNSON, Edmund J. Elder, James E. Hitt, Jonathan C. Evans, True L. Rogers,
The Dow Chemical Company, Dowpharma, Midland, MI
Reports indicate that more than 40% of newly discovered drugs have little or no water solubility.
As a result, the development of many exciting new molecular entities is stopped before their
potential is realized or confirmed because conducting rigorous preclinical and clinical studies on
a molecule that would not have a reasonable pharmacokinetic profile due to poor water solubility
is not economical. Further reports indicate that approximately 16% of marketed drugs have lessthan-optimal performance specifically because of poor solubility and low bioavailability.
Pharmaceutical companies have been able to overcome difficulties with very slightly soluble
drugs; however, those with aqueous solubility of less than 0.1 mg/mL present some unique
challenges. These drugs are particularly good candidates for advanced particle engineering
technologies. Unique nanostructured particles, with enhanced performance attributes, can be
obtained through the control of particle size, particle surface area and particle morphology.
Enhanced dissolution rates (>80% dissolved in 2 min.), improved bioavailability (>2x) and
scale-up (to multi-kilo quantities) has been demonstrated with a portfolio of technologies
including controlled precipitation, emulsions and cryogenic approaches. Particle engineering
technologies produce stabilized particles with enhanced performance characteristics.
7-22
Molecular Configuration of ATP in the Interlayer of Hydrotalcite
H. TAMURA, J. Chiba, M. Ito, T. Takeda, S. Kikkawa; Graduate School of Engineering,
Hokkaido University, Sapporo, Japan, h-tamura@eng.hokudai.ac.jp
Hydrotalcite (HT), a layered double hydroxide of magnesium and aluminum, exchanges its
interlayer anions with those in external solutions, and has been considered to be a potential
vector for anionic medical substances in drug delivery systems. The preparation of well
crystallized pure hydrotalcite with nitrate ions in the interlayer (HT-NO3) and the intercalation of
adenosine triphosphate (ATP) were studied as a model system. It was found that interlayer
nitrate ions were completely exchanged with ATP anions and the average electric charge of the
intercalated ATP was evaluated to be -3.6 from the electric neutrality of the intercalate. The
intercalation of ATP resulted in a doubling of the interlayer distance and the ATP molecules in
the interlayer support a free distance of about 1nm. This distance could be explained by
calculations of the molecular configuration of ATP. The triphosphate group is attached to the
layer of positive charges and the organic molecule group bends owing to its bond angles and
projects to the interlayer with a height of 0.903 nm. The attraction between the organic molecule
groups of ATP stretching between the two opposing layer surfaces is considered to sustain the
layer structure.
7-23
Modulation of the Binding Dynamics of Guests with Bile Salt Aggregates with the Addition
of Co-solvents
Chang Yihwa, CORNELIA BOHNE, Department of Chemistry, University of Victoria, PO Box
3065, Victoria, BC, Canada, bohne@uvic.ca
Bile salts such as sodium cholate (NaCH) and sodium deoxycholate (NaDC) form aggregates in
aqueous solutions with two different binding sites. Primary aggregates, formed at low bile salt
concentrations and have a binding site that is hydrophobic. The association and dissociation
processes for binding of guests to the primary sites are slow. As the concentration of bile salt is
increased the primary aggregates agglomerate into secondary aggregates, where the binding
dynamics is fast.
Guest molecules, which are known to bind exclusive to each site, were used to study the effect
on the binding dynamics by changing the solvent polarity with the addition of acetonitirile or by
changing the viscosity with the addition of ethylene glycol. Addition of ethylene glycol did not
significantly affect the binding dynamics to either binding site. The residence time of guests in
the primary site could be enhanced with the addition of acetonitrile, or decreased by changing the
bile salt from NaCH to the more hydrophobic NaDC. The modulation of the residence time of
guests in each binding site will be employed to explore intra-aggregate reactivity with these
systems.
7-24
Single Surfactant Non-ionic Microemulsions
N. NAOULI, H. L. Rosano, The City College and the Graduate Center of the City University of
New York, 138th Street and Convent Avenue, New York, NY, nnaouli@sci.ccny.cuny.edu
A series of microemulsions, both W/O and O/W were prepared using the point method and
investigated for insight into formation. Two essential characteristics of the interfacial surfactant
film were identified: equal solubility in the oil and water phases (“borderline solubility”), and
positive interfacial tension at the W/O interface. Measurement of surfactant(s) transmittance in
the two phases demonstrates that microemulsification occurs when the surfactant interfacial film
is equally soluble in the oil and water phases. Interfacial and surface tension measurements show
that zero interfacial tension is not necessary for microemulsion formation; further, at the
equilibrium, the interfacial tension must be positive in order to cause the curling of the interface
that enables droplet formation. Calculations of the surfactant molar composition at the interface
allowed us to formulate microemulsions with one single surfactant. This finding allows us to
formulate Lemon oil in water microemulsion with one single emulsifier. Our results suggest that
the structure of the interface is crucial for microemulsion formation and stability.
7-25
The Use of Pluronic Microemulsions for Drug Detoxification: Investigation of the
Interaction Mechanism by NMR Spectroscopy.
M. Varshney1,5, T.E. Morey1,5, E.G. POWELL, M. James2,5, D.O. Shah1,2,5, B.M. Moudgil3,5, R.
Partch6, D.M. Dennis1,4,5, 1Departments of Anesthesiology, 2Chemical Engineering, 3Materials
Science and Engineering, 4Pharmacology & Experimental Therapeutics, 5Particle Engineering
Research Center, University of Florida, Gainesville, FL, 6Clarkson University, Potsdam, NY,
DDennis@ufl.edu
Various Microemulsions (MEs) have been developed to address the problem of the lethal effects
of overdosed drugs. Pluronic MEs efficiently abate the induced cardiotoxicity in living animals.
However, the exact mechanism and important physico-chemical phenomena by which the drug
binds to the ME are not clearly understood and need to be investigated on the molecular level to
improve ME design and further enhance the efficacy of the ME. Pulse NMR spectroscopy is an
expedient technique for elucidating the structural and dynamic interactions between drug and
ME. Investigations were carried out using 1H chemical shift, 13C NMR relaxation and selfdiffusion measurements to determine the ME-drug interaction mechanism. Results indicate that
at low concentrations molecules of the antidepressant, amitriptyline, initially bind with the
hydrophobic portion of the Pluronic but bind to sodium caprylate, with increasing concentration.
A steep increase in the slope of sodium caprylate chemical shift on increasing amitriptyline
concentration compared to the slope of Pluronic indicates that, in addition to the Pluronic
molecules, sodium caprylate molecules in ME617 enhance the amitriptyline binding
significantly. Additionally, self-diffusion studies indicate that amitriptyline binding stabilize the
self-assembly structure of ME617 and show that amitriptyline preferentially binds to the Pluronic
and sodium caprylate molecules than to the ethyl butyrate in the microemulsion.
7-26
Evaluation of AFM for Determining Complexation Forces Between Toxins and Antidote
Molecules
A. BENSON, E. Powell, R. Partch, I. Sokolov, Center for Advanced Materials Processing and
Department of Chemistry, Clarkson University, Potsdam, NY, bensonam@clarkson.edu
Atomic Force Microscopy (AFM) has become a popular instrument over the years for analyzing
the topography of a surface as well as measuring forces between molecules. The sensitivity of
the instrument allows researchers to determine forces between a tip that can be modified as well
as a substrate. This project involves the use and modification of colloid probes to analyze forces
between toxins and antidote molecules. Hydrophobic and - complexation forces between
molecules were measured in both polar and non-polar solvents. Modification of the colloid
probe and substrate will be presented as well as the AFM results.
7-27
Covalent Attachment of Biotin to TiO2 Nanoparticles
LU YE1, Robert Pelton1, Michael Brook2, 1McMaster Centre for Pulp and Paper Research,
Department of Chemical Engineering, 2Department of Chemistry, McMaster University,
Hamilton, ON, Canada, peltonrh@mcmaster.ca
Biotinylated TiO2 nanoparticles (50~150nm) were obtained by treating TiO2 nanoparticles with
3-aminopropyltriethoxysilane (APTES) in an anhydrous DMSO followed by reaction with Nhydroxysuccinimido-biotin. The biotinylated TiO2 was characterized with 13C and 29Si CP-MAS
NMR and FT-IR. The amount of biotinyltriethoxysilane on TiO2 particles was measured by
TGA. The dispersion properties and the mean size of TiO2 particles in different solvents were
studied by transmission electron microscopy (TEM) and dynamic light scattering (DLS),
respectively. The specific surface area (SSA) of TiO2 particles was measured by nitrogen
adsorption before and after the two-step modification. The results demonstrated that the
biotinyltriethoxysilane was covalently bonded to the TiO2 particle surfaces and the mass percent
of biotinyltriethoxysilane is about 1~2.5%. However, the colloidal stability of TiO2 particles was
deteriorated. Anhydrous DMSO was superior to anhydrous toluene in the silanization because
TiO2 colloidal stability was superior in DMSO.
7-28
Characterization of the Complexes between Polyvinylamine and Carboxymethyl Cellulose
X. FENG, R. Pelton, Department of Chemical Engineering, McMaster University, Hamilton,
ON, Canada, fengx2@mcmaster.ca
The complexation of poly (vinylamine) (PVAm) and sodium carboxymethyl cellulose (CMC)
was studied by dynamic light scattering, electrophoretic light scattering, isothermal titration
calorimetry, circular dichroism, and FT-IR spectroscopy. The phase diagram for the complexes
as function of polymer concentration showed that either soluble complexes, colloidal complexes
or precipitated complexes formed depending upon the ratio of the polymers. Dynamic light
scattering indicated that the complexes exhibit a maximum size at 1 mol/L NaCl, suggesting a
strongest interaction at this ionic strength. Moreover, complex molecular weight and density are
dependent on pH and polymer ratio. Electrophoretic light scattering revealed that the colloidal
particles have excess component absorbing on the surface, thus possessing high stability due to
electrostatic repulsion. Isothermal titration calorimetry measurements showed that the
complexation is endothermic at pH > 7 and exothermic at pH 4 whether in addition of PVAm
into CMC or addition of CMC into PVAm. We propose that the complexation of PVAm and
CMC is dominated by electrostatic and hydrogen bonding interactions which vary with pH.
Finally, circular dichroism was used to demonstrate the conformational change of polymer
during complexation.
7-29
Latex Composite Membranes: Structure, Properties, and Applications
CHARLES J. MCDONALD, Dow Chemical Company, Midland, MI [Retired], Consultant:
Southampton, MA, cjm@cjmcdonald.com
We have examined the properties of a new class of microfiltration and ultrafiltration membranes
that are fabricated by assembling particles onto the surface of a microporous substrate and
stabilizing the resulting porous array into a composite. The particle array contains interstitial
voids having a narrow size distribution that serve as channels for size sieving. This aqueous
based technology has advantages relative to other membrane fabrication methods in terms of
highly controlled asymmetry, the facile adjustment of pore sizes, and the ability to easily modify
pore surfaces during the synthesis of particles. In this work we study the properties of the
membranes (gas and water permeabilities) fabricated from different size particles and of varying
thickness on a number of different supports. The experimental data is then analyzed with a
standard model, Carman Kozeny, to develop guidelines for the design of such membranes. For
all of the composites, the volume porosity was found to be approximately 0.3, close to what
would be expected for hexagonal closest packed array which corresponds to the visual
appearance from electron micrographs. In this study, membranes with narrow pore size
distributions from 0.038 m to 0.122 m were fabricated with fluxes 3-4 times higher than the
commercial membranes of similar pore size manufactured by phase inversion processes. This
fabrication method also allows the incorporation of colloidal porous polymer particles for the
adsorption of proteins based on size. This added dimension to the separations carried out with
these membraens are being developed for medical separations such as hemofiltration.
7-30
Development of Supported Lipid Bilayer Cell Membrane Mimics
J.M. TUCKER, R.D. Tilton, T.M. Przybycien, Departments of Chemical Engineering and
Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, jtucker@andrew.cmu.edu
The role of the extracellular matrix (ECM) as a diffusive barrier for proteins approaching the cell
surface is not well understood. Our goal is to quantify this effect using supported lipid bilayer
cell membrane mimics that include ECM mimics. Lipid vesicle adsorption was used to construct
supported lipid bilayers on silica surfaces. Vesicles were formed by an extrusion method and
consisted of egg phosphatidylcholine (egg PC), dinitrophenyl tagged phosphatidylethanolamine
(dNP-PE), and biotinylated lipids. Adsorption to a silica surface was monitored using quartz
crystal microgravimetry with dissipation (QCM-D), and a bilayer conformation was confirmed.
There was negligible nonspecific adsorption of immunoglobulin G (IgG) but significant specific
adsorption of anti-dNP IgG to this bilayer. Thus, an intact lipid bilayer was constructed, and
some dNP is accessible for antibody binding. Hydrophobically-modified hydroxyethyl cellulose
(hm-HEC) or biotinylated hyaluronic acid were anchored to the bilayer and evaluated as ECM
mimics. The effect of ionic strength on the swelling and transport properties of these mimics will
be presented.
7-31
Properties of Monolayers of the Parkinson’s Disease-Related Protein Alpha-Synuclein at
the Air-Water Interface
Daryl A. Bosco, Audra Davis, Jeffery W. Kelly, EVAN T. POWERS, Department of Chemistry,
The Scripps Research Institute, La Jolla, CA
The histological hallmark of Parkinson’s disease is the presence of intracellular inclusions called
Lewy bodies in neurons of the substantia nigra, a region of the brain that controls voluntary
movement. The principle component of Lewy bodies is fibrillar aggregates of the 140-residue
protein alpha-synuclein. Alpha-synuclein is disordered in solution; however, it is highly
amphiphilic, and is known to bind to lipid membranes. Upon membrane binding, it acquires an
ordered, helix-rich structure. Both the natural function of alpha-synuclein and its relationship to
disease are likely to be linked to its amphiphilicity. We have therefore examined the properties
of monolayers of alpha-synuclein at the air-water interface, an environment that is often used to
mimic membranes. We have found that alpha-synuclein self-assembles at the air-water interface,
forming monolayers that appear striated when deposited onto mica substrates and examined by
atomic force microscopy. The factors governing this self-assembly process will be discussed.
7-32
Arraying of Intact Liposomes on Patterned Island Surfaces formed by Micro-contact
Printing of Self Assembled Monolayers
NIKHIL D. KALYANKAR1, Manoj Sharma1, Charles Maldarelli1,3, David Calhoun2, Lane
Gilchrist1, Alexander Couzis1, 1Department of Chemical Engineering, 2Department of
Chemistry, 3Levich Institute, Graduate Center and The City College of The City University of
New York, NY
We are developing protocols to array individual, intact small unilamellar vesicles(liposomes)
onto surfaces with potential application as biosensor probes. In the ongoing research, the
surfaces prepared by Micro-contact Printing (MCP) of islands of microscale and sub-microscale
dimensions using silanes with ‘amine’ (positively charged) terminal groups onto smooth Silica
substrates. Typically the silane used in this step is 3-Aminopropyltrimethoxysilane (APS). These
amine islands are biotinylated using NHS-PEO4-Biotin. The background phase is then put down
using sequential adsorption of Polyethylene glycol (PEG) terminated silanes from solution using
a proper solvent. PEG terminated SAMs are resistant to protein/liposome adsorption. Next step is
to attach Streptavidin to the Biotin islands to form patterned Streptavidin arrays capable of
binding more Biotin. Low Tg Lipid formulations containing 5% Biotinylated lipids are used to
prepare liposomes of 1 micron diameter using extrusion technique. The patterned Streptavidin
grid is then exposed to the Liposome solution, which results in attachment of intact liposomes
onto islands by ‘Biotin-Streptavidin’ interaction specifically onto the Streptavidin grid. The size
of liposomes is matched with the island size so that only one liposome gets attached to each
island. Various steps involved in the protocol are confirmed using Fluorescence microscopy,
Confocal microscopy and Atomic Force Microscopy.
7-33
The Effect of Humidity on the Adsorption Kinetics of Lung Surfactant at Air-water
Interfaces
YI Y. ZUO, Roya Gitiafroz, Edgar Acosta, Zdenka Policova, Peter N. Cox, Michael L. Hair, A.
Wilhelm Neumann, Department of Mechanical and Industrial Engineering, University of
Toronto, Toronto, ON, Canada, yzuo@mie.utoronto.ca
The in vitro adsorption kinetics of lung surfactant at air-water interfaces is affected by both the
composition of the surfactant preparations and the conditions under which the assessment is
conducted. Relevant experimental conditions are surfactant concentration, temperature, subphase
pH, electrolyte concentration, humidity and gas composition of the atmosphere exposed to the
interface. The effect of humidity on the adsorption kinetics of a therapeutic lung surfactant
preparation, Bovine Lipid Extract Surfactant (BLES), was studied by measuring the dynamic
surface tension (DST). Axisymmetric Drop Shape Analysis (ADSA) was used in conjunction
with three different experimental methodologies, i.e. captive bubble (CB), pendant drop (PD),
and constrained sessile drop (CSD), to measure the DST. The experimental results obtained from
these three methodologies show that for 100% relative humidity (RH) at 37 oC the rate of
adsorption of BLES at an air-water interface is substantially slower than for low humidity. These
experimental results agree well with an adsorption model that considers the combined effects of
entropic force, electrostatic interaction, and gravity. These findings have implications for the
development and evaluation of new formulations for surfactant replacement therapy.
7-34
Flow and Particle Transport in a Human Nasal System
PARSA ZAMANKHAN,1,3Goodarz Ahmadi,1,3 Philip K. Hopke,2,3, Sung-Yung Cheng4,
1
Department of Mechanical and Aeronautical Engineering, 2Department of Chemical
Engineering, 3Center for Air Resources Engineering and Science, Clarkson University, Potsdam,
NY, 4Lovelace Respiratory Research Institute, Albuquerque, NM
In this paper a 3D computational model for studying the flow and nano-size particle transport
and deposition in a human nasal passage was developed. The nose cavity was constructed using a
series of pictures of coronal sections of a nose of a human subject. For several breathing rates
associated with low or moderate activities, the steady state flows in the nasal passage were
simulated numerically. The airflow simulation results were compared favorably with the
available experimental data for the nasal passages.
Deposition and transport of ultra fine 1 to 100 nm particles in the cavity for different breathing
rates was also simulated. The simulation results for the nasal capture efficiency were found to be
in reasonable agreement with the available experimental data for a number of human subjects
despite anatomical differences. The computational results for the nasal capture efficiency for
nanoparticles of different sizes and various breathing rate in a laminar regime were found to
correlate with the ratio of particle diffusivity to the breathing rate, or the nose Peclet number. An
improved empirical model for the nose capture efficiency was proposed.
7-35
Particle
Deposition
in
3-D
Asymmetric
Human
Lung
Bifurcations
L. TIAN1,3, G. Ahmadi1,3, A. Mazaheri1,3, Philip K. Hopke2,3, Sung-Yung Cheng4, 1Aeronautical
and Mechanical Engineering Department, 2Chemical Engineering Department, 3Center for Air
Resources Engineering and Science, Clarkson University, Potsdam, NY, 4Lovelace Respiratory
Research Institute, Albuquerque, NM, tianl@clarkson.edu
Accurate predication of micro-scale particle behavior in human upper airway is one of the
prerequisites for effective design of inhalation drug delivery devices. It also could provide
insight into the deposition of contaminants in human respiratory tracks and the nature of personal
exposure. In the past very few works employed 3-D asymmetric model to study the airflow
through human lung, although natural tracheobronchial branching is generally asymmetric, and
such an asymmetry has profound effect on the subsequent flow fields. Also limited work was
devoted to the study of particle depositions in upper airways where the effect of turbulence on
particle depositions is important. This work approaches three of the underlying components to
provide a realistic computational model for lung deposition. The new study include: a realistic 3D asymmetric bifurcation representation of human upper trachea-bronchial tree; simulation of
airflow field characterizing the inspiratory flow conditions in these branches with turbulence
Reynolds stress transport model; and lastly a particle transport model for identifying particle
deposition pattern as well as deposition mechanism in the upper tracheobronchial tree.
8-1
Polymer-Supported Iron Nanoparticles and Microparticles as Remediants for Subsurface
Contaminants
Bianca W. Hydutsky1, Bettina Schrick1, Benjamin Beckerman1, Elizabeth Mack1, THOMAS E.
MALLOUK1, Kaiti Liao2, Kiran Gill2, Christopher Nelson2, Harch Gill2, 1Department of
Chemistry, The Pennsylvania State University, University Park PA, 2PARS Environmental, Inc.,
Robbinsville, NJ, tom@chem.psu.edu
Soil and groundwater contain a legacy of chemical substances - including halogenated organics
and toxic metal ions - from industrial and agricultural processes. A decade ago, scientists at the
University of Waterloo developed a remediation method based on zero-valent iron, which has
since been investigated by numerous researchers. Chemical reduction by iron converts halogencontaining compounds to relatively innocuous hydrocarbons, and reducible metal ions (Cr(VI),
Pb(II), Hg(II), As(V), Tc(VII)) to less soluble forms. Still, the inaccessibility of the deep
subsurface and the large volume of soil or water affected by a chemical spill make the clean up
of contaminants both costly and technically daunting. To address this problem, we have
developed anionic polymers and sulfonated carbons as "delivery vehicles" to transport metal
particles through soils. These polyelectrolyte supports prevent particle aggregation and lower
the sticking coefficient of iron particles in saturated sand and clay soils to ca. 0.01. We find, in
good agreement with theory, that submicron particles have the most favorable transport
characteristics. Field tests show facile injection of iron particle slurries at depths up to 10 meters
and reaction with subsurface chlorinated organic compounds on a timescale of days to weeks.
8-2
Targeted Delivery of Nanoiron to the NAPL-water Interface
N. B. SALEH, K. Sirk, T. Sarbu, G. V. Lowry, R. D. Tilton, K. Matyjaszewski, G. Redden,
Department of Civil and Environmental Engineering, Department of Chemical Engineering,
Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA,
Geoscience Research, Idaho National Laboratory, glowry@andrew.cmu.edu
NAPL source area remediation can decrease mass flux from the site and can expedite
remediation. Nanoiron can rapidly degrade NAPL (e.g. TCE) to non-toxic products in situ, but
methods to deliver it to the NAPL-water interface are needed for efficient use of the iron.
Delivery requires the ability to transport through water-saturated porous media without being
filtered out, and the ability to locate the iron at the NAPL-water interface where it can degrade
NAPL. The approach developed to provide surface functionality to the nanoiron is similar to
targeted drug delivery and may be used to target other specific locations in the subsurface. We
demonstrate here the ability to functionalize the reactive nanoiron particle surface for providing
efficient transport through the subsurface and preferential partitioning to the NAPL-water
interface. Surface modification by amphiphilic block copolymers with highly controllable
properties was used to manipulate the electrostatic repulsive forces of the nanoiron, and to
increase the iron’s affinity for the NAPL/water interface. The results presented here will show
the success of the surface modification in terms of transportability and targeting. Transport of the
nanoiron modified by commercially available conventional surfactants and block co-polymers
was also examined, and results are presented to demonstrate the relative effectiveness of the
synthesized polymer compared to the other modifications. Emulsification of trichloroethylene
using synthesized polymer modified particles will demonstrate the ability of the particles to
localize at NAPL-water interface.
8-3
Synthesis of Magnetite Nanoparticles from Reclaimed Acid Mine Drainage
Roger C. Viadero, Jr., XINCHAO WEI, Department of Civil and Environmental Engineering,
West Virginia University, Morgantown, WV, Roger.Viadero@mail.wvu.edu
The synthesis of magnetite nanoparticles has been the focus of numerous recent research efforts.
In each case, magnetite nanoparticles were formed from reagent-grade chemicals. It is known
that acid mine drainage (AMD) produced through coal mining in the Mid Appalachian region
can produce waters low in pH and high in dissolved metals, of which iron is most abundant. In
this study, Fe was recovered as a ferric hydroxide solid from an AMD water collected from an
abandoned coal mine. After solid-liquid separation, the AMD was neutralized to remove other
dissolved metals. The resulting supernatant met National Pollutant Discharge Elimination
System (NPDES) requirements for discharge. The Fe precipitate was the resolublized and used
for magnetite nanoparticle synthesis via coprecipitation at room temperature under nitrogen
atmosphere. Based on transmission electron microscope (TEM) and scanning electron
microscopy (SEM) observations, most of the magnetite particles ranged from 10 to 15 nm and
were spheroidical in shape. Thus, the synthesis of magnetite nanoparticles with the iron
recovered from AMD was feasible. Consequently, it is possible to address the need for raw feed
stocks in nanoparticle manufacturing, while simultaneously reducing AMD sludge disposal
liabilities.
8-4
Bridging the Gap between Macroscopic and Spectroscopic Studies of Metal Ion Sorption at
the Oxide/Water Interface
L. E. KATZ, C.-C. Chen, M. L. Coleman, A. D. Wiesner, Department of Environmental
Engineering, University of Texas, Austin, TX, lynnkatz@mail.utexas.edu
Metal sorption mechanisms were investigated for strontium, cobalt, and lead sorption onto quartz
and gibbsite using sodium chloride, nitrate, or perchlorate as background electrolytes.
Spectroscopic analyses of concentrated sorption samples were evaluated for their ability to
provide insight into the controlling sorption process for more dilute systems. For strontium,
outer-sphere complexes identified using x-ray absorption spectroscopy (XAS) of concentrated
samples were consistent with macroscopic sorption data collected in more dilute systems. XAS
results indicated that cobalt formed new solid phases with dissolved silica or aluminum on oxide
surfaces. Macroscopic experiments of cobalt sorption supported the spectroscopic data for total
cobalt concentrations of 10-5 M. At lower total cobalt concentrations, adsorption appeared to be
the prevailing mechanism of cobalt removal. Spectroscopic and macroscopic results suggested
that lead adsorbed as an inner-sphere complex on oxides and that the presence of chloride
affected the extent of sorption, respectively. This result was attributed to competition with
aqueous lead-chloride complexes based on thermodynamic calculations. The overriding theme
of the analysis of these data is that neither spectroscopic analysis nor trends in macroscopic data
alone can completely explain the sorption behavior observed in oxide/water systems. The
extrapolation of conclusions drawn from data collected at relatively high surface concentrations
to more dilute systems must be analyzed in conjunction with aqueous phase thermodynamic data.
8-5
Surface Characterization of a Novel Material for Arsenic Removal
Andy Baker1, Katrin Przyuski1, Arthur D. Kney1, STEVEN E. MYLON2, 1Department of
Environmental Engineering, Lafayette College, Easton, PA, 2Department of Chemistry,
Lafayette College, Easton, PA, mylons@lafayette.edu
A selective sorption material composed of iron hydroxide and activated alumina, designated
iron-enhanced activated alumina (IEAA) has proven to successfully remove arsenic to below the
MCL of 10 ppb. In contrast to many other materials developed for the same purpose, IEAA has
the ability to remove both ionic forms of arsenic, (As(III) and As(V)). While the mechanism for
removal of As(V) may be trivial, that for the removal of As(III) is unknown and requires study.
Extended X-ray Absorption Fine Structures (EXAFS) and X-ray Near Edge Spectroscopy
(XANES) have been used for surface characterization of this material in the presence of As(III).
Results from these studies will provide detailed information concerning the coordination
environment of the adsorbed arsenic species on the surface of the IEAA. From this we will can
develop a better understanding of the mechanism for removal of As(III), and hence move to a
more efficient design and synthesis of this IEAA. We will present data from column
experiments demonstrating the efficient removal of As(III) as well as the results from
spectroscopic studies of this material loaded with different forms of Arsenic.
8-6
Novel Nanostructured Anatase Assemblies from Algae as Strong Catalysts for the
Hydrolysis of Organophosphorous Esters
C.-H. HUANGa, S. Leea, S. Shianb, K. H. Sandhageb, aSchool of Civil and Environmental
Engineering, bSchool of Materials Science and Engineering, Georgia Institute of Technology,
Atlanta, GA, ching-hua.huang@ce.gatech.edu, ken.sandhage@mse.gatech.edu
Novel nanocrystalline anatase (TiO2) assemblies were produced from biologically selfassembled SiO2-based diatom microshells (frustules) via a unique reactive conversion technique.
This conversion involves a halide gas (TiF4)/solid displacement reaction that allows for the
complete conversion of SiO2 to TiO2 while preserving the starting bioclastic structure. The
resulting nanostructured anatase frustules were found to strongly catalyze the hydrolysis of
methyl paraoxon and methyl parathion under mild conditions (pH 4.5-9, 25 C), with catalytic
effects of 5-25 times greater than that of other commercial anatase nanoparticles.
Characterization of these anatase nanomaterials revealed isoelectric points in the range of 2.5 to
4.5, which were lower than for typical anatase (pHIEP of 5.2-6.0), indicating stronger surface
acidity. Quantitative fluorine analysis after the conversion reaction indicated that the amount of
residual fluorine in the nanocrystalline anatase played a significant role in the surface acidity and
in the catalytic effect on the hydrolysis of the two organophosphorous esters.
8-7
Comparison of Surface Complexation Models for Predicting Bi-Solute Metal Ion Sorption
onto Iron Oxides
A. R.VIEIRA, S. N. Stokes, C.-C. Chen, L.E. Katz, Department of Environmental Engineering,
University of Texas, Austin, TX, adriano@mali.utexas.edu
Surface Complexation Models (SCMs) hold significant promise as a tool for predicting the fate
and transport of metal ion contaminants. The reliability of SCMs is dependent on the selection
of appropriate surface complexation reactions and accurate estimation of the model parameters.
The past decade has seen significant improvements in model reliability due to increased use of
spectroscopic data for guiding the selection of surface reactions. Yet, many of the intrinsic SCM
parameters are correlated with each other and a wide range of parameter sets can still be used to
fit single-solute adsorption data equally well. One parameter that contributes to data uncertainty
and is required in all SCMs is the surface site density of the adsorbent that is often determined by
fitting experimental data. The estimation of the surface site density using an independent
technique can limit the resulting set of parameters that fit the adsorption data. In our research,
we have shown that site densities estimated using the tritium exchange technique provide better
triple layer model SCM predictions of bi-solute metal ion sorption. In this paper, we extend this
work to provide a comparison of two SCMs, the diffuse layer model and the triple layer model,
for predicting competition of metal ion sorption onto iron oxides over a wide range of
experimental conditions that include adsorption and surface precipitation as the predominant
sorption process.
8-8
Mechanisms Controlling the Release of Trace Elements from Clean-Coal Technology Byproduct: Effect of Proton and Organic Ligands
CHIN-MIN CHENG1, J. Bigham2, H. Walker1, 1Department of Civil and Environmental
Engineering and Geodetic Science and 2School of Natural Resources, The Ohio State University,
Columbus, OH, cheng.160@osu.edu
Despite numerous studies aimed at increasing the utilization of fixated flue gas desulfurization
(FGD) by-products, concern about the leaching of hazardous constituents has limited the
beneficial re-use of these materials. Furthermore, there is a lack of understanding regarding
kinetic processes that control the leaching of trace elements. In this study, the release of trace
elements from fixated FGD material was investigated by considering bulk diffusion, pore
diffusion, and surface chemical reactions as possible rate controlling steps. A flow-through
rotating disk system and shrinking core model (SCM) were used to determine the rate-limiting
process. Experimental results and modeling indicated that the leaching process was controlled
by surface chemical reactions. As a result, the leaching rate can be described by a combination of
an intrinsic hydration reaction and a proton-promoted dissolution reaction. The effects of
organic ligands, i.e., citric acid, oxalic acid, and humic acid, on leaching kinetics were also
investigated under both acidic and near neutral conditions. A ligand-promoted effect was only
observed with citric acid. In the case of oxalic acid, formation of calcium oxalate on the surface
significantly inhibited the leaching process. The adsorption of humic acid selectively inhibited
the leaching of Fe with no significant effect on the leaching of other elements.
8-9
Absorption and Adsorption of Hydrophobic Organic Contaminants to Black Carbon Soots
THANH H. NGUYEN1, Laura A. Langley2, D. Howard Fairbrother2, William P. Ball1,
1
Department of Geography and Environmental Engineering, 2Department of Chemistry, Johns
Hopkins University, 3400 N. Charles street, MD
Single solute sorption isotherms from aqueous solution were obtained for diesel soots and
hexane soots using phenanthrene and 1,2,4-trichlorobenzene as sorbates. Substantial isotherm
nonlinearity was observed in all cases. Compared to sorption with diesel soot SRM 2975,
sorption with diesel soot SRM 1650b was lower at low concentrations but higher at high
concentrations. Pore size distribution and BET surface area (BETSA) were calculated using
nitrogen adsorption data. Comparison between pore size distribution-normalized and BETSAnormalized uptakes for the studied sorbents and those for activated carbon was used to show the
relative importance of surface adsorption to overall uptake. Adsorption dominates for three soots
(SRM 2975, hexane soot, and oxidized hexane soot) at all concentrations and for the fourth soot
(SRM 1650b) only at low concentrations. For SRM 1650b, a dual domain model is required for
description of the total sorption isotherm of both sorbates studied, with absorption dominating
uptake at higher sorbate concentrations.
8-10
Colloids Partitioning between Organic and Aqueous Phase Cause the Low Interfacial
Tension of DNAPL
S.E. Powers, W. DOU, Department of Civil and Environmental Engineering, Clarkson
University, Potsdam, NY, douw@clarkson.edu
Many low Interfacial tensions (IFT) have been observed between some field Dense Non-aqueous
phase liquid (DNAPL) and water comparing to the original organic compounds. But little study
has been done to study the mechanisms lower the IFTs. A DNAPL sample recovered from
Savannah River Site (SRS) of Department of Energy (DOE) also showed an extreme low
interfacial tension (IFT), which is less than 2 Dynes/cm. The main composition of the DNAPL
was analyzed to be about 80% PCE and 20% TCE, which have IFTs of about 45 Dynes/cm and
35 Dynes/cm respectively. When we equilibrated the DNAPL with water, white fine precipitates
are observed to accumulate on the interface. And the further study of the IFT between the SRS
DNAPL and water over time using a picture pendent drop goinometer showed that the
precipitates could account for the substantially lower IFT. The formation of the precipitates can
be reasoned by the partitioning of the co-disposed chemicals accumulating on the interface when
the DNAPL contacts aqueous phase. Research works has been done with a chelating agent
EDTA and tin, which was analyzed to be present in DNAPL to examine the influence of its
presence on the IFT. While no evidence showed that the tin itself can account for the substantial
low IFT of SRS DNAPL.
8-11
Application of ac Electrokinetics in Membrane Filtration Processes
S. H. Molla, S. BHATTACHARJEE, Department of Mechanical Engineering, University of
Alberta, Edmonton, AB, Canada, subir.b@ualberta.ca
A novel combination of ac dielectrophoresis with crossflow membrane filtration is proposed for
separation of the components of aqueous and non-aqueous colloidal systems. The
dielectrophoretic forces experienced by a colloidal entity can be attractive or repulsive depending
on the dielectric properties of the solvent and the dispersed phases and the frequency of the
applied ac signal. Embedding an array of electrodes on a semi-permeable membrane and
actuating them with an appropriate ac signal allows manipulation and separation of the
constituents of a colloidal suspension or microemulsion. The attractive forces can be employed
to preferentially separate the dispersed phase in an emulsion. In contrast, the repulsive
dielectrophoretic forces can be utilized to prevent deposition of colloidal particles on the
membrane. An analysis of the pertinent transport processes during dielectrophoretic membrane
filtration is presented. The simulation results from the trajectory analysis of particles in presence
of dielectrophoretic and hydrodynamic forces indicate: (a) attractive dielectrophoretic forces can
result in a significant enhancement in the transport of the dispersed phase toward the membrane
and (b) repulsive dielectrophoretic forces can prevent colloid deposition onto the membrane and,
hence, membrane fouling, in an entirely physical manner.
8-12
Monte Carlo Simulation of Colloidal Membrane Filtration: Principal Issues for Modeling
JIM C. CHEN2, Menachem Elimelech1, Albert S. Kim2, 1Department of Chemical Engineering,
Environmental Engineering Program, Yale University, P.O. Box 208286, New Haven, CT,
2
Department of Civil and Environmental Engineering, University of Hawaii at Manoa, Honolulu,
HI
The principal issues involved in developing a Monte Carlo simulation model of colloidal
membrane filtration are investigated in this study. An important object for modeling is the
physical dynamics responsible for causing particle deposition and accumulation when
encountering an open system with continuous outflow. A periodic boundary condition offers a
solution to the problem by re-circulating continuous flow back through the system. Scaling to
full physical dimensions will allow for release of the model from flawed assumptions such as
constant cake layer volume fraction and thickness throughout the system. Furthermore, rigorous
modeling on a precise scale extends the model to account for random particle collisions with
acute accuracy. A major finding of this study proves that forces within the colloidal filtration
system are summed and transferred cumulatively through the inter-particle interactions. The
force summation and transfer phenomenon only realizes its true value when the model is scaled
to full dimensions. The overall strategy for model development, therefore, entails three stages,
first, rigorous modeling on a microscopic scale, next, comprehensive inclusion of relevant
physical dynamics, and finally scaling to full physical dimensions.
8-13
Humic Acid Removal with Aminated PGMA Beads
CHANGKUN LIU, Renbi Bai, Department of Chemical and Biomolecular Engineering,
National University of Singapore, 10 Kent Ridge Crescent, Singapore, chebairb@nus.edu.sg
Humic substances are ubiquitous in natural waters and can cause various environmental and
potential health problems. Adsorption has been one of the methods to minimize the presence of
humic substances in water supply. In this study, novel PGMA (poly-glycidyl methacrylate) beads
were prepared and aminated with ethylenediamine (EDA) as an adsorbent to remove humic acid
from aqueous solutions. Zeta-potential analysis was conducted to examine the surface
electrostatic properties, and atomic force microscope (AFM) was used to examine the surface
morphologies of the adsorbent (PGMA-EDA) with and without humic acid adsorption. Fourier
transform infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were
utilized to reveal the surface interactions in humic acid adsorption. It was found that the PGMAEDA adsorbent is very effective in humic acid adsorption and the amine groups play an
important role in interacting with humic acid to be adsorbed. Model fitting study showed that the
adsorption follows a pseudo-second-order (PSO) kinetics.
8-14
Colloids in Subsurface Environments: Aggregation, Deposition, and Facilitated Transport.
MICHAL BORKOVEC, Department of Inorganic, Analytical, and Applied Chemistry,
University of Geneva, Sciences II, 30, Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland,
michal.borkovec@unige.ch
Many transport processes in natural aqueous environments are dictated by colloids and their
interactions. Prominent examples include formation of a river delta or colloid facilitated
transport of contaminants in the subsurface. Mutual interaction between particles and interactions
between particles and surfaces bear many similarities. For example, homoaggregation processes
between identical particles are of relevance in ripening or pore clogging phenomena, while
heteroaggregation processes between unequal particles bear close analogies to particle
deposition. The lecture will discuss several recent techniques and developments allowing us to
study such aggregation and deposition processes experimentally, and the possibility to quantify
those processes with the theory of Derjaguin, Landau, Verwey and Overbeek (DLVO). As an
application of these findings, it will be illustrated how colloid facilitated transport can be
understood on a quantitative basis within a natural soil environment.
8-15
Influence of Alginate and Ionic Composition on the Stability of Hematite Colloids
KAI LOON CHEN1, Steven E. Mylon2, Menachem Elimelech1, 1Department of Chemical
Engineering, Environmental Engineering Program, Yale University, New Haven, CT,
2
Department of Chemistry, Lafayette College, Easton, PA, kailoon.chen@yale.edu
Alginate is a polysaccharide ubiquitous in natural aquatic environments and engineered systems.
It is very likely that alginate absorbs onto colloidal and particulate matter, influencing the fate
and transport of colloids and associated pollutants in aquatic systems. An important
characteristic of alginate is the formation of a cross-linked gel matrix in the presence of calcium
cations. In this study, we characterize the alginate by potentiometric and complexometric
titrations to determine its carboxylic acidity and availability of calcium binding sites,
respectively. We then pre-adsorb synthesized hematite colloids with alginate under favorable pH
conditions. The aggregation kinetics of the alginate-coated hematite colloids is determined by
dynamic light scattering in the presence of monovalent (NaCl) and divalent (CaCl2) electrolytes,
and is compared with the kinetics of the bare hematite colloids. The absolute aggregation rate
constants for both the bare and coated colloids under favorable conditions at high NaCl
concentrations are similar, indicating that they share similar aggregation mechanism of
electrostatic destabilization. In the presence of calcium ions, the growth of the alginate-coated
hematite aggregates is much faster than in sodium ions, implying that the aggregation
mechanisms are different. A discussion of the mechanisms involving the role of alginate will be
presented.
8-16
Effect of Monovalent and Divalent Electrolytes on the Adsorption of Polysaccharides on
Solid Surfaces in Aquatic Systems
ALEXIS J. DE KERCHOVE, Menachem Elimelech, Department of Chemical Engineering,
Environmental Engineering Program, Yale University, P.O. Box 208286, New Haven, CT,
alexis.dekerchove@yale.edu
Polysaccharides play an important role in the fouling of surfaces in natural and engineered
aquatic systems due to their strong adsorptive properties. These highly charged polyelectrolytes
adsorb in compact layers, rendering cleaning of the fouled devices difficult and expensive. In
this study, adsorption of two model polysaccharides, polygalacturonic acid (PGA) and sodium
alginate, was examined as a function of ionic strength and calcium ion concentration utilizing
quartz crystal microbalance with dissipation (QCM-D). The variation of frequency, which
corresponds to the adsorbed polyelectrolyte mass, was analyzed following incremental increases
in the ionic strength and consecutive additions of polysaccharides. PGA had very similar
adsorption patterns as alginate in absence of divalent cations. In presence of calcium, both
polysaccharides demonstrated significant complexation with calcium ions, showing 20 and 10
times greater initial adsorption of PGA and alginate, respectively, than scenarios without
calcium. In most cases, the increase of ionic strength above 100 mM caused a decrease in the
adsorbed mass, suggesting compaction or destruction of the adsorbed polyelectrolyte layer. The
observed adsorption behaviors are discussed in terms of the structure and chemical properties of
the two polysaccharides.
8-17
Effect of Chemical and Hydrodynamic Parameters on Interfacial Retention of Colloids in
Unsaturated Micromodel Channel
V. LAZOUSKAYA, Y. Jin, Department of Plant and Soil Sciences, University of Delaware,
Newark, DE, volha@udel.edu
Transport of colloids and colloid-facilitated transport of contaminants in soil and groundwater
aquifers have been widely acknowledged in the literature. Mineral-grain attachment, air-water
interface and contact line retention are the major mechanisms determining the extent of colloidal
transport in unsaturated porous media. Although unsaturated colloidal transport has been
extensively studied in past years, its complete understanding is pending. The present study
investigates the parameters that affect the behavior of colloids on air-water interface and contact
line. The principal elements of the employed experimental system include a glass channel
micromodel and laser scanning confocal microscope, which allows the visualization of colloidal
systems at the pore scale. The study includes both dynamic (flow) and static experiments. The
flow experiments showed strong influence of hydrodynamic conditions both on air-water
interface and contact line retention whereas the static experiments reflected the effect of solution
chemistry. Applying to natural dynamic systems, the combined effect of chemical and
hydrodynamic conditions on colloidal retention in soil is expected.
8-18
Direct observation of Colloid Deposition at Grain-Grain Contacts in Porous Media Using
X-ray Microtomography
XIQING LI1, C. L. Lin2, Jan D. Miller2, William P. Johnson1, 1Department of Geology and
Geophysics, 2Department of Metallurgical Engineering, University of Utah, Salt Lake City, UT,
li@earth.utah.edu
Colloid deposition at grain-grain contacts is potentially important in porous media. However,
common approaches used to examine colloid deposition (e.g. column experiments) do not
differentiate environments of deposition in porous media. In this work, direction observation of
the environment of deposition was performed using x-ray microtomography (XMT), a technique
that yields exact 3-D representation of the pore domain with a spatial resolution down to 5
micrometers. Near neutrally buoyant microspheres “visible” to x-rays were prepared.
Microsphere suspensions (2.0103 particle-mL-1) were injected into a small column packed with
deposited microspheres were directly characterized. The extent of deposition at grain-grain
contacts was examined with changes in fluid velocity and microsphere size. The maximum
number of microspheres deposited at grain-grain contacts was located increasingly downgradient of the column inlet with increasing flow velocity, indicating the reversibility of
deposition at grain-grain contacts.
8-19
Secondary Minimum Sorption of Microorganisms: Unexpected Prevalence, Implications
and Modeling
L. L. LANDKAMER1, R. A. AbuDalo2, R.W. Harvey1, D.W. Metge1 & J.N. Ryan2, 1U.S.
Geological Survey, Boulder, CO, 2University of Colorado, Boulder, CO
When colloidal particles and collector surfaces have the same charge, deposition is termed
“unfavorable” due to large electrostatic energy barriers inhibiting sorption in the primary
minimum. DLVO calculations often reveal the presence of a secondary minimum (Φ2-min) that
can trap colloids, but Φ2-min sorption is considered unlikely at low ionic strengths. However, we
observed reversible Φ2-min sorption of Cryptosporidium parvum oocysts to clean silica sand at ≤
0.0001 M NaCl. Φ2-min sorption may explain (1) unexpected removal previously attributed to
phenomena such as surface heterogeneities, straining, steric interactions or hydrophobic forces,
and (2) unexpected release of colloids that occur in the presence of slight chemistry changes or
mechanical inputs of energy. The latter may occur because the energy well at the secondary
minimum can be quite shallow (e.g., ≤ 1-2 kBT). A new conceptual model for understanding
colloid filtration in unfavorable conditions was developed by expanding on the work of Hahn
and O’Melia (2004) relating the depth of the Φ2-min and the Maxwell distribution of colloid
energies to detachment probability. Rather than calculating a collision efficiency, all collisions
were assumed to result in attachment and a distribution of detachment rates was used to simulate
colloid transport in porous media.
8-20
Force Interactions Profiles between Cryptosporidium parvum Oocysts and Silica Surfaces
T. L. BYRD, J. Y. Walz, Department of Chemical Engineering, Yale University, New Haven,
CT, tonya.byrd@yale.edu
The interaction force profile between single Cryptosporidium parvum oocysts and silica particles
were measured in aqueous solutions using an atomic force microscope. The oocysts were
immobilized during the measurements by entrapment in a Millipore polycarbonate membrane
with 3 m pore size. Experiments were performed in both NaCl and CaCl2 solutions at ionic
strengths ranging from 1 to 100 to mM. For both electrolytes, the decay length of the repulsive
force profile, obtained via the slope of a plot of the logarithm of the interaction force versus
oocyst/substrate separation, was found to be essentially independent of the ionic strength and
always much larger than the expected Debye length of the system. In addition, the magnitude of
the force was found to be essentially the same for both electrolytes, suggesting that the longrange repulsive forces are strictly steric in nature. The only apparent difference between
experiments in the two electrolytes was that strong adhesive forces were frequently observed in
the calcium solutions. Comparisons of these results with recent particle deposition studies will
also be made.
8-21
Role of Surface Proteins in the Deposition Kinetics of Cryptosporidium parvum Oocysts
ZACHARY A. KUZNAR, Menachem Elimelech, Department of Chemical Engineering,
Environmental Engineering Program, Yale University, P.O. Box 208286, New Haven, CT,
zachary.Kuznar@yale.edu
A radial stagnation point flow system was used to investigate the influence of Cryptosporidium
parvum surface properties on oocyst deposition kinetics onto an ultra pure quartz surface. In
order to determine the role of oocyst surface-bound proteins in adhesion, the deposition kinetics
of viable oocysts were compared with the deposition kinetics of oocysts treated with either heat
or formalin. Low deposition rates and corresponding attachment efficiencies were observed with
viable oocysts over the entire range of solution conditions investigated, even where DLVO
theory predicts the absence of an electrostatic energy barrier. An “electrosteric” repulsion
between viable Cryptosporidium and the quartz substrate, attributed to the proteins on the oocyst
surface, is surmised to cause this low deposition rate. Treatment of the oocysts with either heat
or formalin was found to alter the structure of the surface proteins and reduce steric repulsion
with the quartz substrate. Oocyst surface proteins were then removed with a digestive enzyme
(Proteinase K), and their overall effect on the oocyst electrokinetic properties, and oocyst
deposition rate were determined.
8-22
Profiles of Retained Cryptosporidium Oocysts in Porous Media – Evidence for Dual Mode
Deposition
NATHALIE TUFENKJI, Department of Chemical Engineering, McGill University, Montreal,
PQ, Canada, nathalie.tufenkji@mcgill.ca
Spatial distributions of Cryptosporidium parvum oocysts in columns packed with uniform glassbead collectors were measured over a broad range of physicochemical conditions. Comparison
of oocyst retention with results obtained using polystyrene latex particles of similar size suggest
that mechanisms controlling particle deposition are the same in both systems, that is, “fast”
deposition in secondary energy minima and on favorably charged surface heterogeneities, and
“slow” deposition over electrostatic energy barriers. A dual deposition mode model is applied
which considers the combined influence of “fast” and “slow” oocyst deposition due to the
concurrent existence of favorable and unfavorable colloidal interactions. Model predictions of
retained oocyst profiles and suspended oocyst concentration at the column effluent are in good
agreement with experimental data. Because classic colloid filtration theory does not account for
the effect of dual mode deposition (i.e., simultaneous “fast” and “slow” oocyst deposition), these
observations have important implications for predictions of oocyst transport in subsurface
environments, where repulsive electrostatic interactions predominate.
8-23
Influence of Nutrient Condition on the Adhesion Kinetics of Burkholderia cepacia G4g and
ENV435g
D. Nilasari, S.L. WALKER, Department of Chemical and Environmental Engineering,
University of California, Riverside, Riverside, CA, swalker@engr.ucr.edu
The sensitivity of Burkholderia cepacia G4g and ENV435g adhesion kinetics to nutrient
condition has been observed.
The kinetics of cell adhesion was investigated in a radial
stagnation point flow (RSPF) system under well controlled hydrodynamics and solution
chemistry conditions. Comparable adhesion kinetics were observed for the mutant (ENV435g)
and wild-type (G4) grown in the same medium; however, the adhesion efficiency increased with
the level of nutrient presence for both cell types. To elucidate the cause of the deposition
sensitivity to nutrient condition, complimentary cell characterization techniques were conducted
to evaluate the viability, hydrophobicity, electrophoretic mobility, and size of cells grown in both
nutrient rich Luria broth (LB) and poor basal salts media (BSM) growth media. Additionally,
the charge density, as well as the polysaccharide and protein content of the extracellular
polymeric substances (EPS) were evaluated under the differing nutrient presence. Nutrient
condition was found to alter cell deposition due to its impact on the EPS composition and size
characteristics of the cells.
8-24
Bio-Colloid Facilitated Metal Transport in Geologic Media: Observations and Surface
Complexation Modeling
L.L. LANDKAMER1, R.W. Harvey1, D.W. Metge1, J. N. Ryan2,1U.S. Geological Survey,
Boulder, CO, 2University of Colorado, Boulder, CO
Bench-scale experiments demonstrated enhanced Zn(II) and Pb(II) transport in flow-though
columns packed with either iron/aluminum-oxide coated sand or limestone chips when bacteria
were injected with the metal, relative to experiments performed without bacteria. In a column
packed with limestone chips, the effluent concentration of zinc injected in the presence of
bacteria (Pseudomonas stutzeri, 8.5 × 107 cells/ml) was 8-fold higher than when no bacteria were
injected. The transport of zinc in a column packed with sand was enhanced 13-fold in the
presence of 1.1 × 108 cells/ml. The bacteria were pre-starved and no carbon source was present,
so it is assumed that the bacteria sorbed and transported the metal independently of cellular
metabolism. The pH dependence of the enhanced transport was modeled using surface
complexation chemistry coupled with a transport model. The surface complexation model
simulates the competition for the metal between the organic functional groups on the bacterial
surfaces and the inorganic functional groups on the geologic media surfaces. The specific
sorption reactions used to model the metal sorption to the bacteria and the geologic media will be
discussed along with the strategy used to model bacterial transport in the framework of the
contaminant transport model.
8-25
Deposition and Re-entrainment Dynamics of Microbes and Non-Biological Colloids during
Non-Perturbed Transport in Porous Media in the Presence of an Energy Barrier to
Deposition
W.P. JOHNSON, X. Li, M. Tong, S. Assemi, Department of Geology & Geophysics, University
of Utah, Salt Lake City, UT, wjohnson@mines.utah.edu
This presentation examines the non-perturbed deposition and re-entrainment dynamics of
biological and non-biological colloids in porous media in the presence of an energy barrier to
deposition at the grain surface. Deposition and re-entrainment rate coefficients were determined
from numerical simulation of breakthrough-elution behavior and the profiles of retained colloids.
Results are presented for non-biolog
ionic strength and fluid velocity conditions. In the presence of an energy barrier, deposition
efficiencies decreased with increasing fluid velocity for all colloids and conditions examined. In
the presence of an energy barrier, re-entrainment rate coefficients increased with increasing fluid
velocity. These results demonstrate that in the presence of an energy barrier to deposition,
hydrodynamic drag mitigates deposition and drives re-entrainment of both biological and nonbiological colloids. The possibility of colloid association with the primary energy minimum is
considered via a balance of hydrodynamic and adhesive torques. The possibility of colloid
association with the secondary energy minimum is considered via reversibility of deposition; and
via parallel experiments in porous media and simple shear flow systems.
8-26
Real-time Observation of Colloid Transport in Porous Media at Mesoscales Using Epifluorescence Imaging
Y. Wang and P. ZHANG, Department of Earth and Atmospheric Sciences, City College of New
York, New York, NY, pzhang@sci.ccny.cuny.edu
The lack of direct, continuous observation of the movement of colloids in porous media limits
our knowledge of the processes that control colloid transport and immobilization in these media.
Here we developed a non-evasive, epi-fluorescent imaging technique to quantify the distribution
of fluorescent microspheres in translucent sand at mesoscales (maximum view area of 20 cm by
20 cm). Carboxylated latex microspheres were injected into a flow cell (20 cm long by 10 cm
wide by 1 cm thick) packed with clean quartz sand at various flow rates and ionic strengths, and
then eluted with microsphere-free solution of identical chemistry. Nonmonotonic colloid
distribution profiles were observed in all transport experiments under unfavorable deposition
conditions. Direct observation and comparison of the 1-D distribution profiles at different elution
times (up to 6 pore volumes) clearly showed a down-gradient movement of microspheres during
elution, suggesting that the nonmonotonic distribution profiles observed in this particular study
was due to the detachment of retained microspheres.
8-27
Role of Zones of Low Hydrodynamic Drag in Colloid Deposition and Re-entrainment in
Porous Media
MEIPING TONG, W.P. Johnson, Department of Geology & Geophysics, University of Utah,
Salt Lake City, UT, tong@earth.utah.edu
Existing colloid deposition models assume that attached colloids are not subject to hydrodynamic
drag, whereas recent experiments demonstrate that in the presence of electrostatic repulsion
hydrodynamic drag mitigates colloid deposition and drives colloid re-entrainment. The
deposition and re-entrainment behaviors of three different-sized carboxylate modified
polystyrene latex microspheres were systematically examined in packed porous media and
impinging jet systems under various fluid velocity conditions. Deposition efficiencies were
compared between the porous media and impinging jet systems to determine the influence of
zones of low hydrodynamic drag on colloid deposition. At the end of the experiments, the
porous media and the impinging jet experiments were eluted with pure water to deepen the
barrier to detachment from primary energy minima, and to eliminate secondary energy minima.
The extent of release of retained colloids upon elution with pure water indicated the significance
of primary and secondary energy minima to colloid deposition. The results indicate the
importance of grain surface angularity in the generation of zones of low hydrodynamic drag that
enhance colloid deposition in porous media.
8-28
Deposition and Characterization of Nanoparticulate FeS on Quartz Surfaces for
Remediation of As(III) Contaminated Groundwater
TANYA J. GALLEGOS1, Kim F. Hayes2, Linda M. Abriola3, 1Department of Civil and
Environmental Engineering, 181 EWRE, 1351 Beal Avenue, Ann Arbor, MI, 2Department of
Civil and Environmental Engineering, 181 EWRE, 1351 Beal Avenue, Ann Arbor, MI, 3Tufts
University, 105 Anderson Hall, Medford, MA, tgallego@umich.edu, ford@umich.edu,
Linda.Abriola@tufts.edu
Nanoscale synthetic FeS (mackinawite) has been found to be effective at removing As(III) from
solution under anoxic conditions over a wide range in pH values. This is due both to the large
surface area of nanoscale FeS and because this form of FeS provides a readily available source of
sulfide for As(III) precipitation as an As-S solid. To utilize FeS for implementation as a reactive
media in permeable reactive barriers (PRB), and in order to avoid potential permeability
reduction or loss of particles that may be caused by nanoparticulate FeS forms, we have been
testing the feasibility of coating quartz sand particles with nanoscale FeS. Since both quartz sand
and nanoscale FeS exhibit negative surface charge over nearly the entire pH range, these
particles tend to repel one another and thus present a challenge for developing effective coatings.
This study reports quartz surface modifications that are being used to make it more amenable for
electrostatic self-assembly by nanoscale FeS. The ultimate goal of this work is to produce a
highly reactive surface FeS surface coating on quartz sand while maintaining the reactive
properties of nanoscale FeS for As(III) removal from groundwater in PRB applications.
8-29
Homogeneous Nucleation in the Ambient Atmosphere
PHILIP K. HOPKE, Center for Air Resources Engineering and Science and Department of
Chemical Engineering, Clarkson University, Potsdam, NY
One of the important recent findings has been that homogenous nucleation in the atmosphere is a
much more common event that had been previously been recognized. Initially these events were
observed in remote areas such as Hyytiälä, Finland and Mace Head, Ireland. However, recently
these events have been found to occur in urban areas in the presence of a preexisting aerosol.
Measurements made in Atlanta, Pittsburgh, and Rochester have shown that two types of events,
plume and regional. In plume events, short term bursts of nanometer-sized particles (10 to 20
nm) are observed in the late morning/early afternoon time period. In the regional events, the
nucleation burst if followed by condensational growth leading to particles in the 60 to 80 nm
range. The nature of the nucleation process and the potential effect of such events on the
properties of the atmospheric aerosol will be discussed.
8-30
Direct Force Measurements between Carboxylate-Modified Latex Microspheres and a
Glass Surface Using Atomic Force Microscopy
SHOELEH ASSEMI1, Jakub Nalaskowski2, William Paul Johnson1, 1 Department of Geology
and Geophysics, 2 Department of Metallurgical Engineering, University of Utah, Salt Lake City,
UT, wjohnson@mines.utah.edu
Interaction and adhesion forces between 1.0-modified polystyrene latex
microspheres and a glass surface were measured directly with an atomic force microscope using
the colloidal probe technique. Measurements were conducted as a function of ionic strength in
two different electrolytes, NaCl and MOPS (3-(N-morpholino)-propanesulfonic acid) buffer, at
pH 6.8-6.9. AFM approach curves were fitted to theoretical DLVO force curves by varying the
surface potential of the microspheres. The depths of the primary minima of the fitted theoretical
DLVO curves were used to estimate theoretical adhesion forces, and were compared to the pulloff forces measured by AFM. Pull-off forces measured by AFM in both electrolytes were
consistently a factor of 5 to 10 lower than the pull-off forces estimated from theoretical adhesion
forces obtained from DLVO curves. AFM-measured pull-off forces decreased with increasing
the ionic strength in both electrolytes, whereas the adhesion forces calculated from DLVO
showed either no change or an increase with increasing the ionic strength. These observations
indicate that the DLVO-based approach for determining adhesion force severely overestimates
the actual adhesion force.
8-31
Development and Use of a Bioluminescent Biosensor for Assessing the Bioavailability of
Organic Pollutants in Surfactant Micelles
Angela Keane1, Peter C.K. Lau2, SUBHASIS GHOSHAL1, 1Department of Civil Engineering,
McGill University, Montreal, PQ, Canada, 2Biotechnology Research Institute, National Research
Council, Montreal, PQ, Canada, subhasis.ghoshal@mcgill.ca
A direct measurement technique for microbial bioavailability was developed using a whole-cell
bioluminescent biosensor, PpF1G4. To create PpF1G4, bioluminescent reporter genes (lux) were
placed under the control of the promoter region of the solvent efflux pump genes (sep) in
Pseudomonas putida F1. Biosensor PpF1G4 produces a bioluminescent response to a wide range
of aromatic compounds. PpF1G4 was used to evaluate how three nonionic surfactants (Triton
X-100, Brij 30 and Brij 35) influence the bioavailability of three different organic pollutants
(toluene, naphthalene, and phenanthrene) present as individual compounds in solution in excess
of solubility as well as the bioavailability of multiple solutes partitioned from non-aqueous phase
liquid multi-component mixtures such as coal tar and creosote. The increased bioluminescent
response of PpF1G4 in micellar solutions of Triton X-100 and Brij 35 indicated higher intracellular concentrations of the test compounds, toluene, naphthalene and phenanthrene, compared
to control systems with no surfactants present. The above results and transmission electron
microscope images of PpF1G4 in micellar surfactant solutions suggest that nonionic surfactants
may enhance bioavailability and biodegradation rates by increasing the mass flux of substrates
present in the micellar pseudophase to the cells through mechanisms that do not involve visible
changes to membrane permeability.
8-32
Mixed-Order Modeling of Simultaneous Particle and Dissolved Substrate Removal by
Aerobic Biological Film Wastewater Treatment Systems
J. P. BOLTZ1, C. H. La Motta2, 1M. CH2M HILL , Inc., Montgomery, AL, 2Urban
Environmental Systems Center and University of New Orleans, New Orleans, LA,
jpboltz@uno.edu
Several mechanistic models have been developed to describe the kinetics of dissolved substrate
utilization by biological films, or biofilms. These models, however, have limited application
when the primary constituent of chemical oxygen demand in domestic wastewaters is organic
particles. Recent research has demonstrated that frequently a small fraction of the total chemical
oxygen demand (TCOD) in raw sewage and primary effluents is dissolved. Therefore, there is a
need to develop a mathematical expression capable of describing the removal of simultaneous
particulate and dissolved organic matter from wastewaters. The primary objective of this
research project is to study the kinetics of particulate COD (PCOD) removal from wastewaters
by biological films and apply the respective kinetic expression to a model that includes
phenomena such as diffusion and reaction of dissolved substrate inside the biofilm, and the
simultaneous flocculation of organic particles at the external film surface. The resulting mixedorder model is validated using a laboratory scale completely mixed biofilm reactor.
8-33
High Performance Carbon Honeycomb for Air Separation
K. LASZLO1, G. Onyestyák2, E. Geissler3, 1Department of Physical Chemistry, Budapest
University of Technology and Economics, Budapest 1521, Hungary, 2Institute of Surface
Chemistry and Catalysis, Chemical Research Center, Hungarian Academy of Sciences, H-1525
Budapest 3Laboratoire de Spectrométrie Physique CNRS UMR5588, Université J. Fourier de
Grenoble, B.P.87, 38402 St Martin d'Hères cedex, France, klaszlo@mail.bme.hu
Carbon adsorbent materials are of paramount importance in environmental technology, from gas
purification and separation to gas storage or catalyst supports. These processes rely on specific
pore size distributions that contribute to selective adsorption via size exclusion. Low temperature
nitrogen adsorption, small angle X-ray scattering (SAXS) and frequency response (FR)
measurements are reported for carbon prepared by heating wood from scotch fir (Pinus
sylvestris) in an inert atmosphere to temperatures in the range 600°C ≤ T ≤ 1000°C. The
honeycomb structure, conserved from the original wood, provides easy access for gas adsorption
and air separation applications. The surface area measured by gas adsorption, SBET, and the
microporosity both increase with increasing T, while significant mesoporosity develops at
1000°C. Although the samples are highly anisotropic at distance scales greater than 10 nm, the
specific surface area SX derived from SAXS is isotropic within experimental error. FR
measurements of the adsorption rate of nitrogen and oxygen reveal strong selectivity in favour of
oxygen for the 700°C sample, whose characteristic slit width is approximately 0.33 nm. For
T=1000°C, the slit width doubles and the selectivity disappears.
9-01
Methanol Oxidation to Methyl Formate and Dimethoxymethane on Supported RuO x and
H3PVxMo12-xO40 Clusters
Haichao Liu, ENRIQUE IGLESIA, Department of Chemical Engineering, University of
California at Berkeley and E.O. Lawrence Berkeley National Laboratory, Berkeley, CA,
iglesia@cchem.berkeley.edu
RuOx and H3PVxMo12-xO40 clusters catalyze CH3OH oxidation to methyl formate (MF) and
dimethoxymethane (DMM) at near ambient temperatures. DMM synthesis involve bifunctional
redox-acid pathways favored by acidic supports. The concurrent formation of dimethylether can
be inhibited by titration of acid sites with organic bases to form stable pyridine-polyoxometallate
(POM) composite catalysts with high DMM selectivity. Reaction pathways involve catalytic
redox cycles using lattice oxygen atoms on active oxides to form primary formaldehyde products
and secondary reactions of methoxymethanol or hemiacetal intermediates to form MF on
supports containing dehydrogenation functions (ZrO2, SnO2) and DMM on acidic supports
(Al2O3, SiO2). Kinetic and isotopic studies showed that initial HCHO synthesis is limited by CH bond activation on lattice oxygens on both RuOx and POM clusters.
9-02
Chemistry-Aided Design of Future Clean Fuels
EDWARD L. SUGHRUE, Uday T. Turaga, Bartlesville Technology Center, ConocoPhillips
Company, Bartlesville, OK
Clean fuels are the result of a continuum of changes in the chemical composition of gasoline and
diesel. The removal of lead from gasoline in the 1970s, the addition of oxygenates in the 1990s,
and the current removal of sulfur each impacted the chemical composition of fuels.
Understanding the interaction between fuel composition and process chemistry enables not only
optimal application of current refining processes but also development of new approaches to
produce clean fuels. For example, utilizing detailed analyses of the distribution of sulfurcontaining molecules in refinery streams, reactor models are now used to both design new
hydrodesulfurization units and integrate them with existing units. Similarly, molecular analyses
of gasoline streams suggest methods to minimize octane loss during the production of ultra-low
sulfur gasoline. These and other examples will be used to discuss the impact of future clean fuel
requirements on fuel composition and processing.
9-03
The Role of Liquid Products in Catalyst Pores for Influencing Product Olefin
Readsorption and Hydrocarbon Chain Initiation in Fischer-Tropsch Synthesis
R. J. MADON1, E. Iglesia2, 1Engelhard Corporation, Iselin, NJ, 2Department of Chemical
Engineering, University of California, Berkeley, CA, Rostam.Madon@Engelhard.com
During Fischer-Tropsch synthesis, catalyst pores are filled with waxy liquid product
hydrocarbons. This liquid phase helps to increase the overall reaction rates for the readsorption
of product -olefins which in turn increase hydrocarbon chain initiation. This results in nonlinear Flory product distribution and the formation of a heavier more paraffinic product slate.
We use transition state theory to show that higher olefin readsorption rates of larger olefins are
not the result of higher solubility of olefins in the liquid phase. Increasing olefin solubility is
either unimportant for olefin readsorption, or, under certain circumstances, would actually
increase the tendency of adsorbed olefins to desorb rather than of solvated olefins to readsorb.
Thus the olefin solubility – physisorption model is inconsistent with transition state theory and
with experimental observations. Instead, the liquid hydrocarbon phase within catalyst pores
introduces an intraparticle transport limitation on the olefin products as they exit these pores.
These intraparticle diffusion limitations induce fugacity gradients that lead to the observed
enhanced olefin adsorption as olefin size increases within catalyst pores.
9-04
C-H Bond Activation by Platinum
GABOR A. SOMORJAI, Department of Chemistry and Lawrence Berkeley National
Laboratory, University of California, Berkeley, CA, Somorjai@Berkeley.edu
C-H bond activation for several alkenes (ethylene, propylene, isobutene, cyclohexene, and 1hexene) and alkanes (methane, ethane, n-hexane, 2-methylpentane, and 3-methylpentane) has
been studied on the (111) crystal face of platinum as a function of temperature at low (< 10-6
Torr) and high (1 Torr) pressures in the absence and presence of hydrogen pressures (10 Torr).
Sum frequency generation (SFG) vibrational spectroscopy has been used to characterize the
adsorbate structures and high pressure scanning tunneling microscopy (HP-STM) has been used
to monitor their surface mobility under reaction conditions during hydrogenation,
dehydrogenation, and CO poisoning. C-H bond dissociation occurs at low temperatures ~250 K,
for all of these molecules, although only at high pressures for the weakly bound alkanes because
of their low desorption temperatures. Bond dissociation is known to be surface structure
sensitive and we find that it is also accompanied by the restructuring of the metal surface. The
presence of hydrogen slows down dehydrogenation and for some of the molecules it influences
the molecular rearrangement, thus altering reaction selectivity. Surface mobility of adsorbates is
essential to produce catalytic activity. When surface diffusion is inhibited by CO adsorption,
ordered surface structures form and the reaction is poisoned. Ethylene hydrogenation is surface
structure insensitive, while cyclohexene hydrogenation/dehydrogenation are structure sensitive.
n-Hexane and other C6 alkanes form either upright or flat lying molecules on the platinum
surface that react to produce branced isomers or benzene, respectively.
9-05
Parameter Estimation in Nonlinear Models when the Estimates Really Matter
S. Aydogan, J. Caruthers, N. Delgass, S.-H. Hsu, F. Ribeiro, V. Venkatasubramanian, G.BLAU,
S.Orcun Department of Chemical Engineering and Discovery Park, Purdue University, West
Lafayette, IN, blau@ecn.purdue.edu
Classical Nonlinear Design of Experiments and Analysis Strategies are available for
discriminating rival kinetic models for catalytic reaction systems and for generating minimum
variance parameter estimates for the model selected. These methods are rarely used because of
the lack of understanding of their statistical underpinnings by the modeling community, the
convenience of linear statistical methods and companion hostility of nonlinear estimation
procedures, and finally, the lack of importance of high quality parameter estimates. The ushering
in of the era of design informatics has changed this paradigm. It is now critical to estimate high
quality microkinetic rate constants and use them as response variables to characterize other
physiochemical properties of the catalyst. The power and storage capabilities of the high speed
computers are now making it possible to realize design and analysis capabilities which permit the
relaxing of questionable assumptions in classical methods while simultaneously providing a
more user friendly environment. In this talk we will define and illustrate the need and
consequence of applying Markov Chain/MonteCarlo procedures to Bayesian estimation to
generate high quality parameter for a simple reaction system. A novel adaptive gridding
technique developed to address the computation challenges will also be presented. Finally,
generalization of the procedures introduced to more complex system will be discussed.
9-06
Mobility of Catalytic Nanoparticles
ABHAYA K. DATYE1*, Thomas Hansen1, Mangesh Bore1, Qing Xu1, Ron Goeke1, Lani
Miyoshi Sanders1, Brian Swartzentruber2, 1University of New Mexico, Albuquerque, NM,
2
Sandia National Laboratories, Albuquerque, NM
Sintering of catalysts is an important mechanism for catalyst deactivation. The active phase in
these catalysts consists of nanosized metal particles, which can transform at elevated
temperatures into particles as large as few hundreds of nanometers leading to loss of activity and
selectivity. One of the proposed mechanisms involves the migration and coalescence of
nanoparticles. Models for catalyst sintering assume that the diffusion of nanoparticles on
surfaces scales with (particle diameter)n, where the exponent n can vary from -4 to -7. Such
models imply that as particles grow in size, the rates of migration and coalescence will slow
down. In this work, we will report systematic studies of the migration of nanoparticles on oxide
surfaces at sizes ranging from a few atoms to several tens of nanometers. We have used a
variety of techniques, ranging from scanning tunneling microscopy, scanning electron
microscopy as well as transmission electron microscopy. We also performed Monte Carlo
simulations of nanoparticle dynamics. The results provide many surprises and show that the
phenomenon of nanoparticle mobility is very complex and involves several competing
mechanisms.
9-07
Scanning Transmission Electron Tomography and Supported Nanoparticle Catalysts
JOHN MEURIG THOMAS*, Paul A. Midgley, Dept. of Materials Science, University of
Cambridge, Cambridge, United Kingdom, Davy Faraday Research Laboratory, The Royal
Institution of Great Britain, 21, Albemarle St., London,United Kingdom
It is desirable to develop non-destructive methods of determining the distribution of subnanometer metallic and bimetallic catalysts supported on highly porous oxides. In particular, the
location of nanoparticle Pt-Ru catalysts, which exhibit high activities and selectivities in the
hydrogenation of polyenes and other organic compounds, needs to be precisely determined when
the siliceous support is composed of non-ordered nanopores of average diameter ca 6 nm. The
advantage of doing so using dark-field (rather than bright-field) annular scanning electron
microscopy, which can also be adapted to retrieve the elemental composition of individual
particles weighing as little as a few zeptograms (10-21g), will be outlined.
9-08
A New Approach to Obtain Highly-Dispersed Supported Ru/SiO2 Catalysts
S. SOLED, A. Malek, S. Miseo, J. Baumgartner, C. Kliewer, M. Afeworki, P. A. Stevens,
ExxonMobil Research and Engineering Company, Annandale, NJ
Preparation of metal catalysts is an old field with few new directions discussed in either the
academic or patent literature. Most supported metal catalysts are prepared from the
corresponding supported metal oxides, classically by incipient wetness impregnation of solutions
containing metal salts, followed by drying and then calcination to form the oxides. By changing
the preparation method, the interaction between the supported oxide and the support changes,
which in turn modifies reducibility and dispersion of the supported metal. Here we report a new
approach specifically for preparing well-dispersed supported Ru catalysts on silica. We show
that partially oxidizing a Ru- triethanolamine impregnate on silica forms a strongly interacting
precursor, which bonds to and spreads on the support. This precursor avoids the necessity of
using rigorous anaerobic conditions or esoteric precursors to form supported organometallic
complexes. Reduction of this Ru-precursor creates tiny metal crystallites homogeneously
distributed on silica, in sharp contrast to what occurs via traditional impregnation routes. This
homogeneous distribution also leads to enhanced resistance to reductive sintering, which we
clearly demonstrate by chemisorption and TEM techniques. We present preparation,
characterization and aromatic hydrogenation data to illustrate this new technique of preparing
supported Ru catalysts.
9-09
Poisoning and Deactivation of Cobalt-based Fischer-Tropsch Catalysts By ppm And Subppm Level Reactive Nitrogen Compounds
S. C. LEVINESS, H. J. Robota, X. Zhan, J. Engman, Syntroleum Corporation, Tulsa, OK,
sleviness@syntroleum.com
Sulfur poisoning of cobalt Fischer-Tropsch catalysts has been known since the earliest days of
the technology, and is the subject of numerous scientific publications, including a number by
Prof. Bartholomew in the 1980s. More recently extensive work has been conducted in the area
of cobalt FT catalyst deactivation due to surface oxidation and/or spinel formation due to high
water concentrations and/or water-to-hydrogen ratios. Part per million levels of reactive nitrogen
compounds – mainly ammonia, with smaller amounts of hydrogen cyanide and possibly nitrogen
oxides – are typically formed in synthesis gas generation processes. The patent literature
contains numerous claims for the need, and methods, to remove these compounds from FT
synthesis gas feeds but to date very little/no published information exists regarding the actual
details of nitrogen compound induced poisoning/deactivation.
We have investigated the effects of NH3, HCN, and NOx both when added to laboratory fixed
bed and slurry autoclave synthesis gas feeds and when present in real autothermal
reformer/catalytic partial oxidation synthesis gas in a pilot plant scale slurry bubble column
reactor. The results of these studies indicate markedly different effects from nitrogen than from
sulfur or water induced deactivation mechanisms. The presence of reactive nitrogen compounds
initially causes a rapid, though limited, loss of activity. In this regime the deactivation rate is
directly proportional to the nitrogen compound feed space velocity. During this phase, the
number of impacted sites appears larger than the number of nitrogen atoms involved, but is
limited to suppressing activity by only about 35%. Continued operation yields much lower
further deactivation rates that are only weakly dependent on the nitrogen compound
concentration and space velocity. Nitrogen poisoned catalysts operated with clean synthesis gas
feeds show a very slow reactivation, but essentially 100% activity can be easily restored through
a relatively mild in-situ hydrogen treatment.
9-10
Spectroscopic Identification of Carbonaceous Species on Silica-Supported, and PlatinumPromoted Iron Fischer-Tropsch Catalysts
CALVIN H. BARTHOLOMEW, Jian Xu, Catalysis Laboratory and Department of Chemical
Engineering, Brigham Young University, Provo, UT, bartc@byu.edu
Carbonaceous surface species and bulk iron carbides formed under commercially-relevant
Fischer-Tropsch synthesis (FTS) conditions on moderately dispersed, high-activity silicasupported iron catalysts (Fe/SiO2, FePt/SiO2 and FePtK/SiO2) were spectroscopically
characterized. Bulk iron phase compositions were determined by Mössbauer spectroscopy, and
phase transformations of carbonaceous species during pretreatment with CO, H2, or H2/CO and
following reaction were characterized using temperature-programmed hydrogenation (TPH).
Isothermal transient rates of FTS were also measured for catalysts after different pretreatments.
Six surface and bulk carbonaceous species were quantitatively identified from combined TPH
and high-pressure Mössbauer spectra of the FePtK catalyst; They include, in order of decreasing
reactivity: (a) adsorbed, atomic carbon (C ); (b) amorphous, lightly poly-merized hydrocarbon
or carbon surface species (C
2.2C and Fe2.5C); and (d)
disordered and moderately-ordered graphitic surface carbons. The distribution of active and
inactive carbon species varies with pretreatment and time-on-stream. A correlation between the
amount of reactive α-carbon (Cα) and initial catalytic activity after different pretreatments was
observed. The method of Li et al.1 for deter-mining irreversible chemisorption of CO does not
measure active site densities on silica-supported iron quantitatively. Nevertheless, specific
activity based on H2 chemisorption after reaction may be proportional to active site density.
Models, based on this and pre-vious work, are proposed for iron phase and carbon phase
transformations in silica-supported iron during pretreatment, FTS, and post-reaction
passivation/oxidation.
9-11
Structure-function Relationships in Pd-Au Catalysts
D. WAYNE GOODMAN, Department of Chemistry, Texas A&M University, College Station,
TX, goodman@ mail.chem.tamu.edu
Model mixed-metal catalysts consisting of Pd alloyed with Au as bulk films on refractory metal
single crystals and as nanoparticles supported on oxides have been characterized using an array
of surface techniques including X-ray photoemission spectroscopy (XPS), low energy ion
scattering spectroscopy (LEIS), Auger electron spectroscopy (AES), low energy electron
diffraction (LEED), infrared reflection absorption spectroscopy (IRAS), metastable impact
electron spectroscopy (MIES), scanning tunneling microscopy (STM), temperature programmed
desorption (TPD), and reaction kinetics. The surface sensitivity of LEIS and IRAS has been
exploited for elucidating atomic composition of the outermost surface layer. Of special interest
is the composition of the surface compared to the overall composition, particularly in
transitioning from planar surfaces to nanoparticles, in the presence and absence of adsorbates.
The mechanistic details of the vinyl acetate synthesis reaction, used to probe the structurefunction relationship of these alloy surfaces, will also be discussed.
9-12
The Nature of the Active Sites in Au/TS-1 Catalysts for Propene Epoxidation by Oxygen
and Hydrogen
B. Taylor, L. Cumaranatunge, A. M. Joshi, K.T. Thomson, W. N. DELGASS, School of
Chemical Engineering, Purdue University, West Lafayette, IN, delgass@ecn.purdue.edu
Partial oxidation of propylene to propylene oxide (PO) by H2 + O2 over Au/TS-1 as a function of
TS-1 particle size showed the number of active sites to be limited and that reaction may occur
within the TS-1 crystallites. Catalysts prepared with low titanium and low gold loadings
confirmed the presence of a small number of very active Au/Ti sites, formed more efficiently at
low loadings. A catalyst consisting of 0.01 wt % Au on TS-1 with a Si/Ti = 500 was found to
have the highest activity per gold atom yet reported (350 gPO hr-1 gAu-1 at 200°C). These
catalysts were also shown to have an inherent gold uptake that, when exceeded, produced
inferior PO rates and stability. Density functional theory (DFT) results showed that hydrogen
peroxide could be produced catalytically from oxygen and hydrogen over gas phase Au3, Au4+,
and Au5-, favored in that order. TS-1 synthesized in the presence of carbon pearls gave the
highest activity per gram catalyst (132 gPO hr-1 kgcat-1: 0.33 wt % Au on TS-1 with a Si/Ti = 28,
200°C). We conclude that H2O2 is the oxidant and that small clusters of Au atoms near Ti are
viable sites for PO production.
9-13
Poisoning, and Fouling of V2O5/TiO2 SCR Catalysts by Ash from Coal- and Biomass-Fired
Boilers
WILLIAM C. HECKER, Xiaoyu Guo, Aaron Nackos, John Ashton, Calvin H. Bartholomew,
Larry L. Baxter, Brigham Young University, Provo, UT
A comprehensive study of deactivation of V2O5/TiO2 SCR catalysts by ash minerals from coaland biomass-fired boilers was undertaken at laboratory and small pilot plant scales. Laboratory
activity tests to determine effects of poisoning by basic ash components were conducted on
commercially-relevant 1% V2O5/9% WO3 / TiO2 catalysts pre-impregnated with various levels of
soluble Na and Ca compounds. These experiments simulate possible poisoning of “dusted” SCR
catalysts during exposure to flue gas below the dew point. Significant losses of activity with
increasing Na or Ca concentrations are observed, although at Na/V and Ca/V ratios greater than
one, activity level approaches a constant low value which is nevertheless still measurable. Loss
of activity is significantly greater for Na relative to Ca compounds. These results suggest that
substantial loss of activity is associated with adsorption of basic cations on the acid sites of
V2O5/TiO2, although poisoning of sites is not complete at saturation coverage by the poison.
Surface sulfation by SO2 of 1-5% V2O5/TiO2 catalysts during reaction, on the other hand,
increases catalytic activity. In situ FTIR spectroscopy and XPS analyses indicate that SO2 is not
adsorbed as a sulfite or sulfate on vanadia sites but rather on titania sites. Sulfation by SO2 also
enhances NH3 adsorption on Brønsted acid site but not on Lewis acid sites; this suggest that
sulfation may occur on sites at the interface of vanadia surface species and TiO2. NO reduction
activity of both fresh and sulfated vanadia catalysts increases due to an increase in the number of
active sites without changing activation energy.
Five commercial vanadia-based catalysts and a monolith catalyst prepared at BYU were tested
over several thousand hours in a small pilot plant reactor using slipstreams from commercial
boilers in which coal and biomass-coal blends served as fuels. Post mortem, laboratory activity
studies of the monolith catalysts after various exposure times indicate that fouling and plugging
rather than poisoning are the main deactivation mechanisms for vanadia catalysts under
commercial operation.
9-14
Renewable Liquid Alkanes from Aqueous-Phase Processing of Biomass-Derived
Carbohydrates
G. W. HUBER, J. N. Chheda, C. J. Barrett, J. A. Dumesic, Department of Chemical Engineering,
University of Wisconsin, Madison, WI, dumesic@engr.wisc.edu
Concerns about global warming, national security and the diminishing supply of fossil fuels are
causing our society to search for new renewable sources of transportation fuels. Domestically
available biomass has been proposed as part of the solution to our dependence on fossil fuels. In
this respect, we have recently developed catalytic processes to convert biomass derived
molecules to liquid alkanes, which could be used as transportation fuel. Alkanes ranging from
C1 to C6 can be produced by aqueous phase dehydration/hydrogenation (APD/H) of sorbitol
(hydrogenated glucose) by a bi-functional pathway. Sorbitol is repeatedly dehydrated by a solid
acid (SiO2-Al2O3) or a mineral acid (HCl) catalyst and then hydrogenated on a metal catalyst (Pt
or Pd). Larger liquid alkanes ranging from C7-C15 can be produced by APD/H of larger
carbohydrate-derived molecules. The biorefining of sugars to alkanes plus CO2 and water is an
exothermic process in which the products retain approximately 95 % of the heating value and
only 30 % of the mass of the reactant.
9-16
Recyclable Polymerization Catalysts – Silica-Tethered CuBr-Bipyridine Atom Transfer
Radical Polymerization Catalysts
C. W. JONES, J. V. Nguyen, School of Chemical& Biomolecular Engineering, Georgia Institute
of Technology, Atlanta, GA, cjones@chbe.gatech.edu
It is well-known that most chemical products made on a moderate to large scale are produced in
a process that utilizes solid catalysts, as the use of solid catalysts facilitates easy product
recovery and repeated catalyst use. However, a notable exception to this trend exists in the area
of polymerization catalysis, where most catalysts are single-use entities. For this reason, they are
engineered to give extremely high productivities to achieve low residual catalyst content in the
final polymers.
Nonetheless, there are many emerging polymerization technologies that produce unique new
polymers from old monomers that are commercially very attractive. However, many of them,
like atom transfer radical polymerization (ATRP), require a large amount of catalyst that must be
effectively recovered and ideally recycled to facilitate potential commercial application. Indeed,
ATRP is an attractive technology because it allows for the preparation of well-defined polymers
such as block copolymers due to the quasi-living/”controlled” nature of the polymerization.
Unfortunately, ATRP requires a relatively high catalyst loading that results in significant metal
residue in the final polymer. Thus, a recoverable, recyclable catalyst would be a useful advance.
The construction of solid catalysts for polymerization requires different design rules than
catalysts for small molecule transformations. In particular, the role of porosity, or a lack thereof,
plays a critical role. Here we report our recent studies into the design of recoverable, recyclable
ATRP catalysts based on silica supported CuBr complexes of bipyridine and
pyridylmethanimine. The roles of synthetic method, catalyst porosity, and ligand structure are
evaluated in the catalytic polymerization of methyl methacrylate. Additionally, a new catalyst
regeneration method is introduced and an effective, recyclable system for the controlled
polymerization of methacrylate monomers is achieved.
9-17
Naturally Chiral Surfaces
Andrew J. Gellman, Joshua D. Horvath, A. Koritnik, D. RAMPULLA, Department of Chemical
Engineering, Carnegie Mellon University, Pittsburgh, PA
Single crystalline surfaces terminated in structures with kinked steps have inherent chirality. The
enantioselective properties of these surfaces have been explored using both temperature
programmed desorption (TPD) and Fourier Transform - Infrared Reflection Absorption
Spectroscopy (FT-IRAS) measurements. The adsorption of R-3-methylcyclohexanone (R-3MCHO) has been shown to be enantioselective on the several different kinked Cu surfaces. TPD
measurements show distinct, resolvable features associated with desorption from the terraces,
steps, and kinks on the surface. The desorption kinetics from the kinks depend on the relative
handedness of the adsorbate and the surface. The decomposition of chiral alkyl groups including
2-butyl and 2-methyl-butyl have been studeied on the Cu(531) and Cu(643) surfaces. Their
decomposition by β-hydride elimination yields a number of products and the product yields have
been shown to depend on the relative handedness of the alkyl groups and the Cu surfaces. These
results suggest that naturally chiral surfaecs can be used for enantioselective chemical processes
such as hetergeneous catalysis or separations.
9-18
NO Oxidation Reaction Kinetics on Pt/Al2O3 Catalyst
S.S. Mulla, N. Chen, W. N. Delgass, W. S. Epling†, F. H. RIBEIRO, School of Chemical
Engineering, Purdue University, West Lafayette, IN, †Cummins, Inc., 1900 McKinley Ave,
Columbus, IN, fabio@purdue.edu
The oxidation of NO to NO2 over a supported noble metal component is an important step
involved in NOx abatement techniques, e.g., selective catalytic reduction (SCR) and NOx
storage/reduction (NSR) processes being developed for lean-burn diesel engines to limit their
NOx emission. We demonstrate here the kinetics of NO oxidation reaction on a Pt/Al2O3
catalyst.
The
rate
equation
for
the
reaction
was
determined
to
be
1.05 0.08
1.03 0.08
0.92  0.07
r  k[NO]
[O 2 ]
[NO 2 ]
, with k as the rate constant. Thus, the product NO2
inhibits the forward rate and this makes it imperative to include the influence of NO2
concentration in any analysis of the kinetics of this reaction. The apparent activation energy was
82 kJ mol-1 ± 9 kJ mol-1. We also propose a reaction mechanism consisting of elementary
reaction steps that attempts to explain the observed kinetics. We will also discuss our attempts to
understand the effects of Pt particle size on this reaction. Our experimental results indicate that
the Pt particle size affects the NO oxidation turnover rate (TOR) significantly, with larger Pt
particles giving a higher TOR. These findings are crucial to optimize the oxidation of NO to
NO2, and hence the overall NSR process.
9-19
Surface Properties of Supported Gold and Alloy Nanoparticle Catalysts
Jin Luo+, Mathew M. Maye+, Nancy Kariuki+, Lingyan Wang+, Peter Njoki+, Derrick Mott+, Yan
Lin+, Mark Schadt+, Stephanie I-Im Lim+, Vivian W. Jones+, CHUAN-JIAN ZHONG*,
Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, +3M
Corporation, cjzhong@binghamton.edu
We have recently been investigating core-shell assembled gold and alloy nanoparticle catalysts
for electrocatalytic oxidation of carbon monooxide and methanol and reduction of oxygen, which
are of interest to the development of fuel cell catalysts. The exploitation of the catalytic activity
of such materials requires the ability to manipulate the interparticle spatial and surface access
properties in controllable ways. This ability is inherently linked to the controllable activation of
the nanostructure in terms of size and surface properties. This paper reports recent findings of
our investigations in probing the structural and morphological evolution of molecularly-capped
metal nanoparticles on different support materials under thermal treatment using atomic force
microscopy (AFM), infrared spectroscopy (FTIR), X-ray Diffraction (XRD), and X-ray
Photoelectron Spectroscopy (XPS). The results demonstrate that the nanocrystal size and surface
binding sites can be controlled by a combination of factors including adhesion, mobility,
composition, activation energy and surface tension. These findings have important implications
to the design and processing of advanced nanostructured catalysts.
9-20
Electro-catalytically Performance Improvement of La1-xSrxCo1-yFeyO3 (LSCF) Cathodes
Formed Using the Sol-Gel Method
LOUISE J.B. LIU, Viola V. Birss, Dept. of Chemistry, University of Calgary, Calgary, AB,
Canada, jlouise@clarkson.edu
La1-xSrxCo1-yFeyO3 (LSCF) perovskite cathodes display significantly better performance than
LaxSr1-xMnO3 (LSM) because of their high catalytic activity for O2 reduction, and their very
good ionic and electronic conductivity. The sol-gel (SG) method, combined with low processing
temperatures, has become increasingly popular for the preparation of metal oxides, due to its
advantages of producing materials with high porosity, high surface areas, and homogeneity on
the molecular scale. In the present work, SG methods have been employed to synthesize LSCF
cathode and 2 mol% samaria-doped ceria electrolyte. The structure phase, morphology, particle
size and elemental composition of the SG-LSCF cathodes was obtained using XRD, HRTEM,
SEM and WDS. Electrochemistry was carried out in a 3-electrode half-cell configuration,
exposed to air. The cathode so-prepared is found to be primarily composed of the LSCF
tetragonal phase and its crystallite size ranges between 20-30 nm. SEM showed that the SGLSCF cathode layer is ca. 30 m thick and has highly structured channels with thin walls and
pores on the order of a micron or less in diameter. HRTEM images of a typical particle indicate
the presence of a highly crystalline plane (101) with a few stacked faults. In terms of the
cathode’s electrochemical performance, the specific area resistance of the cathode at 700 oC
averaged to ca. 0.30 ·cm2, which was substantially better than that obtained by the traditional
synthesis technology.
9-21
Liquid-Phase Reductive Deposition as Novel Preparation Method of
Hybrid Nano-particulate Catalysts
ATSUSHI MURAMATSU, Yoji Sunagawa, Sarantuya Myagmarjav, Hideyuki Takahashi,
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1,
Katahira, Aoba-ku, Sendai, Japan
Nanoparticles have been received much attention and been widely studied, since its property can
change only by the size because of quantum effect when the size is reduced to nanometer level.
The decrease of the size is also expected to enhance the catalytic activity, because the decrease
in size results in the increase of the total surface area and active sites with unsaturated bonding.
Among various methods to synthesize the nanometer-sized particles, the liquid-phase reduction
method is one of the easiest procedures, since nanoparticles can be directly obtained from
various precursor compounds soluble in a specific solvent. We have taken Ni as an example of
target nano-material and then reported that Ni and Ni-Zn nanoparticles with a diameter from 5 to
10nm and an amorphous-like structure were synthesized by using liquid-phase reduction method
and that Zn addition to Ni nanoparticles promote the catalytic activity for 1-octene
hydrogenation. However, unsupported particles finally lost their activity due to tremendous
aggregation because of its high surface activity. In order to solve this problem, we have been
developing the selective deposition method onto TiO2 nanoparticles, named as the liquid-phase
selective-deposition method, where TiO2 plays a role of formation center of Ni nanoparticles as
well as protection from aggregation and growth of the particles. In this paper, I will focus on the
concept of this method and the detailed formation mechanism of Ni-Zn/ TiO2 nanocomposite.
Nanoparticles synthesized was dispersed and stabilized by the selective deposition onto TiO2
surface. The particle size was decreased with increasing the amount of Zn added, thus the
catalytically active Ni surface area was increased. The selective deposition onto TiO 2 surface
and addition of Zn to the nanoparticle promoted the catalytic activity of Ni-Zn nanoparticle, e.g.
the catalytic activity of Ni-Zn/TiO2 was ca. 10 times higher than that of the unsupported Ni
nanoparticles. Ni in the nanocomposite was assigned as metallic, although their surface was
oxidized under the atmospheric condition, but Zn and B were deposited as their oxide.
9-22
Active Media Effect on Strength and Durability of Catalysts
E. D. SHCHUKIN1,2,3, A. I. Bessonov1, L. N. Sokolova1, S. I. Kontorovich1, L. N. Burenkova2,
B. V. Romanovsky2, 1Institute for Physical Chemistry of the Russian Acad. Sc., Moscow
117915, Russia; 2Moscow State University, Moscow, Russia; 3Johns Hopkins University,
Baltimore, MD, shchukin@jhu.edu
The mechanical wear facilitated by the medium influence can be a principal cause of catalyst
losses in many heterogeneous catalytic processes. The direct experiments with MgO, Co-Mo,
Ca-Ni-P, Al-Cr-K and other catalysts show that both their strength and durability decrease
significantly, sometimes dramatically during catalysis with respect to identical tests in the inert
media. The effect has been explained as the thermodynamically predicted result of the mutual
influence of solid phase and medium in catalytic process: new bonds arising between them may
cause bonds weakening and rupture both in adsorbed molecules and in solid surface (i.e.,
Rehbinder effect manifestation). In this aspect, catalyst is a victim of its destination. However,
the resistance of catalyst granules to wear can be essentially improved by perfecting their
technology: selection of optimal size grading of the granule forming particles and strengthening
contacts between these particles, using nano-disperse inactive fillers and hydration hardened
mineral binders, reducing residual internal stresses, etc. Catalysis assisted rupture of surface
bonds may result also in creating new surface adatoms and, correspondingly, in accelerating the
surface selfdiffusion and particles sintering, i.e., in the increase in strength, or achieving the
same interparticle contacts development and strength at lower sintering temperatures (Catalysis
Enhanced Sintering - CES). This has been recently shown both for metals (Fe, Ni) and ceramics
(alumina, zirconia, yttria) powder samples.
9-23
Synthesis of Nanosized TiO2-SiO2 Complex Particles and Their Photocatalytic Activity
G. W. ZHOU1, Y. Y. Wang1, Z. Y. Shao1, G. Y. Xu2, G. Z. LI2, 1School of Light Chemical and
Environmental Engineering, Shandong Institute of Light Industry, Jinan, China; 2Key Laboratory
for Colloid and Interface of Ministry of Education of China, Shandong University, Jinan, China,
guoweizhou@hotmail.com
Titania-silica (TiO2-SiO2) nanoparticles were prepared by sol-gel procedure with mix up
hydrolyzed titania-sol(TBOT as a titanium precursor) and silica-sol (TEOS as a silica precursor).
These nanoparticles were then characterized by X-ray powder diffraction (XRD), transmission
electron microscopy (TEM), Scanning electron microscopy (SEM)-energy dispersive X-ray
analysis (EDX), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-Vis)
spectroscopy, Raman spectroscopy and thermogravimetric/differential thermal analysis
(TGA/DTA). The analytical results demonstrated that the complex of SiO2 with TiO2 can
increase the phase transformation temperature of TiO2 and enhance the thermal stability of TiO2
structure, no rutile phase was observed for the TiO2-SiO2 particles up to 800 0C. The
micrographs of TEM and SEM showed that the TiO2-SiO2 particles had a spherical and a narrow
size distribution 60~80 nm. The Raman spectra indicated that the nanoparticles showed highly
broadened with the blue shift of the anatase features at lower temperature and the peaks
sharpened as the temperature increased. In addition, TiO2-SiO2 particles showed high
photocatalytic activity on the photocatalytic decomposition of phenol and its derivatives.
10-01
Evaluation of Decoherence for Quantum Control and Computing
V. PRIVMAN, Center for Quantum Device Technology, Clarkson University, Potsdam, NY,
privman@clarkson.edu
Different approaches in quantifying environment induced decoherence are considered. We
identify a measure of decoherence, derived from the reduced density matrix of the system, that
quantifies the environmentally induced error, i.e., deviation from the ideal isolated-system
dynamics. This measure can be shown to have several useful features. Its behavior as a function
of time has no dependence on the initial conditions, and is expected to be insensitive to the
internal dynamical time scales of the system, thus only probing the decoherence-related time
dependence. For a spin-boson model—a prototype of a qubit interacting with environment—we
also demonstrate the property of additivity: in the regime of the onset of decoherence, the sum of
the individual qubit error measures provides an estimate of the error for a several-qubit system,
even if the qubits are entangled, which is important in quantum-computing applications. This
makes it possible to estimate decoherence for several-qubit quantum computer gate designs.
10-02
Spins in Semiconductors for Storing and Processing Quantum Information
H. W. JIANG, Department of Physics and Astronomy, University of California at Los Angeles,
Los Angeles, CA, jiangh@physics.ucla.edu
Spins in semiconductors have many desirable properties for quantum information processing.
Recent key experimental demonstrations by several groups have considerably improved the
prospects of physical implementation of a semiconductor based processor. In this talk, I will
highlight the recent progress of the UCLA group. The results of an experiment to manipulate
single spin with microwave pulses and to detect its magnetic resonance and spin orientation will
be reported. Effort on the fabrication and characterize long-coherent-time qubits on epitaxial
SiGe heterostructures will be described. The first demonstration of trapping, storing, and
detecting single photoelectrons in a controllable electrostatic quantum dot will also be presented.
10-03
Efficient Wave-Induced Switching & Quantum-NOT Operation in Coupled Quantum
Wires
A. Ramamoorthy,1 J. P. BIRD,2, 1Nanostructures Research Group, Department of Electrical
Engineering, Arizona State University, Tempe, AZ, 2Department of Electrical Engineering,
University at Buffalo, the State University of New York, Buffalo, NY, jbird@buffalo.edu
Coupled quantum wires have been proposed as a means to realize a scalable solid-state based
qubit for quantum computing Both Gaussian-wave-packet, and plane-wave, based
implementations of this approach have been explored theoretically, along with schemes for
entanglement and the realization of multi-qubit networks. In spite of this interest, however, there
has been little experimental progress on this problem to date. In this presentation, we present the
results of a first practical step towards the implementation of this approach, providing evidence
for the successful demonstration of a single qubit structure comprised of two coupled GaAs
quantum wires. Our experimental results reveal extremely efficient switching of the electron
wavefunction (by nearly 100%) between the two waveguides of this structure, and also show
evidence for the proposed quantum-NOT operation in which an incoming electron wave is
switched effectively from one waveguide to the other. This behavior is observed to temperatures
as high as 35 K, suggesting the considerable potential of this approach. In our presentation we
also speculate on the possibility of extending our results to achieve entanglement of coupled
qubits based on this system.
10-04
Transmission Coefficient for an Electron Through a Quantum Point Contact in an Electric
and Magnetic Field
M.L. GLASSER1, N.J.M. Horing2, K. Sabeeh3, Department of Physics and Center for Quantum
Device Technology, 1Clarkson University, Potsdam, NY, 2Department of Physics and
Engineering Physics, Stevens Institute of Technology, Hoboken, NJ, 3Department of Physics,
Quaid-i-Azam University, Islamabad, Pakistan, laryg@clarkson.edu
Electron transmission through a quantum point contact (QPC) in the presence of an electric and
magnetic field is examined. The QPC is modeled as a saddle potential. The relevant Green
function is derived using Schwinger’s operator equation of motion method and used to obtain the
transmission coefficient. For vanishing electric field the result reduces to Fertig and Halperin’s
result.
10-05
Mesoscopic and Microscopic Spin Injection, Spin Precession, Spin Diffusion and Spin
Transport in Semiconductor Nanostructures
M. W. WU, Hefei National Laboratory for Physical Sciences at Microscale University of Science
and Technology of China Department of Physics, University of Science and Technology of
China Hefei, Anhui, China, mwwu@ustc.edu.cn
In this talk we are going to present our theoretical investigations on spin kinetics of
semiconductor nanostructures based on many-body, single particle and mesoscopic approaches
under various conditions. Both transient and steady-state transports are addressed. In addition to
the cases near the equilibrium, spin kinetics far away from the equilibrium such as electrons of
high spin polarization and/or electrons with strong electric field (hot electrons) is also discussed
in detail. Many novel effects are predicted.
10-06
Irreversible Deposition of Particles on Pre-Treated Surfaces
A. CADILHE, N. Araújo, GCEP-Centro de Física, Universidade do Minho, 4710-057 Braga,
Portugal, cadilhe@fisica.uminho.pt
We present a Monte Carlo study of irreversible, competitive deposition models, applied to
single- and two-sized disks on pre-treated, patterned surfaces with short-range repulsive
interactions. In particular, we study the effect of the substrate nanopatterning on coverage and
particle distribution on the surface. Definition of suitable dimensionless parameters in terms of
natural length scales of these systems can provide information regarding the “phase diagram”
and obtain, therefore, the structure of the jamming state in several limiting cases of interest.
Depending on the values of the parameters, the presented model is capable of describing,
amorphous, continuum Random Sequential Adsorption, or locally ordered regions. We also
performed simulations with an initial fraction of dirt already deposited on the substrate. Our
study is of interest to people working, for example, in the fields of self-assembled
nanostructures, colloids, lithography, and nonequilibrium statistical physics as it provides key
parameters and characterization of the evolution towards the jamming state.
10-07
Synthesis and Applications of Monofunctional Gold Nanoparticles
J. G. Worden, Q. Dai, X, Liu, Q. HUO, Department of Coatings and Polymeric Materials, North
Dakota State University, Fargo, ND, qun.huo@ndsu.edu
In the bottom-up approach towards nanomaterial development, there are two most important
aspects to be addressed: one is the synthesis of nanobuilding blocks and the other one is how to
assemble the nanobuilding blocks together into materials or devices with precisely controlled
structures, properties and functions. Recently our group developed a unique solid phase
technique to synthesize gold nanoparticles with a single functional group attached to the surface.
Using the monofunctional gold nanoparticles as molecular nanobuilding blocks, we further
demonstrated the synthesis of covalently bonded nanoparticle/polymer hybrid materials by
chemical reactions. This research provides a promising tool in the precise positioning of
nanoparticles to a particular location of a substrate or scaffold material, and its applications in
quantum computing and quantum devices will be discussed in the presentation.
10-08
Decoherence of a Quantum System and Dynamics of a Heat Bath
S. SAIKIN, Center for Quantum Device Technology, Department of Electrical and Computer
Engineering, Clarkson University, Potsdam, NY, Department of Physics, Kazan State University,
Kazan, Russia, saikin@clarkson.edu
The traditional approach to evaluate dissipation processes in a classical system interacting with
an external reservoir is based on the Markov approximation. In this case evolution of a system
possesses a semi-group property and is local in time. It was shown that for a quantum system this
approximation is valid only on timescales larger than the thermal time,  / kT .
In most non-markovian models for evolution of open quantum systems the bath is described by a
set of non-interacting oscillators. I will consider how an internal interaction between modes of a
thermal bath affects semi-group property and characteristic timescales of irreversible dynamics
of a quantum system.
10-09
Collective Decoherence of Nuclear Spin Clusters
A. FEDOROV, Center for Quantum Device Technology, Department of Physics and Department
of Electrical and Computer Engineering, Clarkson University, Potsdam, NY 13699-5721,
fedorov@clarkson.edu
The problem of dipole-dipole decoherence of nuclear spins is considered for strongly entangled
spin cluster. Our results show that its dynamics can be described as the decoherence due to
interaction with a composite bath consisting of fully correlated and uncorrelated parts. The
correlated term causes the slower decay of coherence at larger times. The decoherence rate scales
up as a square root of the number of spins giving the linear scaling of the resulting error. Our
theory is consistent with recent experiment reported in decoherence of correlated spin clusters.
10-10
Loss of Coherence in Gate-Controlled Qubit Systems
D. SOLENOV, Center for Quantum Device Technology, Department of Physics and Department
of Electrical and Computer Engineering, Clarkson University, Potsdam, NY,
solenovd@clarkson.edu
Studies of decoherence for quantum computing has been based on investigation of an idling
qubit system described by a time-independent Hamiltonian. We present an approach that allows
investigating the influence of essentially time-dependent gate controls on coherence of qubit
system. The approximation to the reduced density matrix is obtained to the leading order in
system-to-environment interaction. In the case of an adiabatic settings the approximation is
shown to give decoherence behavior of the exact solution. The approach is analyzed on the
example of a qubit in the rotating wave field.
10-11
Single-Photon Optical Detectors Based on Superconducting Nanostructures
R. SOBOLEWSKI, Department of Electrical and Computer Engineering and the Laboratory for
Laser Energetics, University of Rochester, Rochester NY, roman.sobolewski@rochester.edu
We review the current state-of-the-art in the development of superconducting single-photon
detectors and demonstrate their advantages over conventional semiconductor avalanche
photodiodes, in terms ultrafast and very efficient counting capabilities of both visible-light and
infrared photons. Superconducting single-photon detectors (SSPDs) are quantum photon
counters. Their detection mechanism is based on photon-induced generation of a picosecond
voltage transient across a nanostructured, 1010-m2-area NbN meander (4-nm-thick and ~100nm-wide stripe). Our best devices operate at 2 K and exhibit quantum efficiency of ~30% in the
-GHz photon counting rate, timing jitter of <18 ps, and
dark counts <0.01 per second. The SSPDs have already been applied in testers for debugging of
VLSI CMOS circuits and are currently being implemented for free-space optical
communications and in fiber-based quantum key distribution (cryptography) systems. Transition
edge sensors (TESs) are superconducting nanobolometers and they act as super-sensitive
thermometers. TES devices reach quantum efficiency of >80%, have negligible dark counts, and
possess photon number resolving capability. They are excellent x-ray detectors with ~1-eV
energy resolution and are expected to find applications in linear optical quantum computation.
10-12
Decoherence and Loss of Entanglement
D. TOLKUNOV and V. Privman, Center for Quantum Device Technology, Department of
Physics, Clarkson University, Potsdam, NY, tolkunov@clarkson.edu
We review our recent work establishing by an explicit many-body calculation for an open
quantum-mechanical system of two qubits subject to independent noise modeled by bosonic
baths, a new connection between two important issues in the studies of entanglement and
decoherence. We demonstrate that the decay of entanglement is governed by the product of the
suppression factors describing decoherence of the subsystems (qubits). This result is the first
detailed model calculation proving an important and intuitively natural physical property that
separated open quantum systems can evolve coherently, quantum mechanically on time scales
larger than the times for which they remain entangled.
Our result also suggests avenues for future work. Specifically, for multiqubit systems, it is
expected that similar arguments should apply “by induction.” This will stimulate research to
develop appropriate quantitative measures of entanglement, and attempts to quantify
entanglement and decoherence in a unified way.
10-13
Frequency Study of the Microwave Induced Resistance Oscillations of a High Mobility
Two-Dimensional Electron Gas
S. A. STUDENIKIN1, M. Byszewski2, D.K. Maude2, M. Potemski2, A. Sachrajda1, M. Hilke3, L.
N. Pfeiffer4, K. W. West4, 1Institute for Microstructural Sciences, National Research Council of
Canada, Ottawa, ON, Canada, 2Grenoble High Magnetic Field Laboratory, MPI/FKF and CNRS,
BP 166, 38042 Grenoble, Cedex 9, France, 3Department Of Physics, McGill University,
Montreal, QC, Canada,4Bell Laboratories, Lucent Technologies, Murray Hill, NJ,
sergei.studenikin@nrc.ca
Microwave induced resistance oscillations (MIROs) detected on high mobility samples have
attracted much interest recently. Under certain conditions a zero-resistance state is observed.
We have investigated the evolution of MIROs on a GaAlAs/GaAs heterostructure (μ~107cm2/Vs)
over a very wide frequency range from ~50 GHz up to ~4 THz, from quasi-classical to the
quantum Hall regime. At low frequencies regular MIROs were observed, with a periodicity
determined by the ratio of microwave to cyclotron frequencies. For frequencies below 150 GHz
the MIROs waveform vs magnetic field is well described by the existing theoretical models that
can be used for deducing the Landau levels width.
At higher frequencies the weak MIROs were still observed on a background of relatively strong
Shubnikov de Haas oscillations. The MIROs progressively vanished at higher frequencies,
around 400 GHz. This sets an upper frequency limit for the observation of MIROs. However,
microwave induced resistance changes are still observed at frequencies above 400 GHz in the
form of sharp peaks at the cyclotron resonance and its second harmonic. The observed resistance
changes in the quantum Hall regime could be qualitatively understood in terms of a bolometrictype response.
10-14
The Influence of Weak Measurement on Electron Transport in Quantum Dots Chains
L. FEDICHKIN, D. Solenov, Center for Quantum Device Technology, Department of Electrical
and Computer Engineering, Department of Physics and Department of Mathematics and
Computer Science, Clarkson University, Potsdam, NY, leonid@clarkson.edu
We consider the chain of semiconductor quantum dots with neighboring dots coupled by tunnel
barriers with one electron coherently hopping from one dot to another. The corresponding
quantum walk behavior of electron transport is strongly affected by measurement via quantum
point contacts placed nearby each dot. We derive the evolution of electron density matrix and
analyze the transition from coherent quantum oscillatory dynamics to diffusive classical motion.
10-15
On Quantum Walks on Graphs
C. TAMON,Department of Mathematics and Computer Science, Clarkson University, Box 5815,
Potsdam, NY, tino@clarkson.edu
Random walk on graphs is a valuable algorithmic technique in computer science. The recent
interest in quantum walks on graphs is fueled in part by the positive impact of the classical
paradigm, but also in part by the possibility of exploiting natural physical processes for an
implementation of a quantum model of computation. To date, there are two known models of
quantum walks, discrete and continuous-time, with their respective algorithmic potential. We
outline some recently proven structural properties about quantum walks on some well-known
graphs, along with some preliminary work on analyzing mixing and decoherence.
10-16
Ballistic Electro Photonics
V. NARAYANAMURTI, Division of Engineering and Applied Sciences and Department of
Physics, Harvard University, Cambridge, MA, venky@harvard.edu
The ballistic transport of hot electrons in semiconductors has long been a subject of interest. In
this talk, I will present several exciting new results which have broad implications for the study
of new semiconductor nanostructures including the transport of spin. These are:
Ballistic Electron Emission Luminescence which allows the simultaneous monitoring of electron
transport and luminescence for quantum dot structures placed below the surface.
Demonstration of several new types of hot electron based devices involving the monitoring of
spin transport. Examples include luminescent spin valve transistors and spin valve photodiodes.
Transport and luminescence studies of semiconductor nanowires such as ZnO.
10-17
Ab Initio Analysis of Electron-Phonon Coupling in Molecular Devices
H. GUO, Center for the Physics of Materials and Department of Physics, McGill University,
Montreal, QC, Canada, guo@physics.mcgill.ca
We report first principles analysis of electron-phonon coupling in molecular devices under
external bias voltage and during current flow. Our theory and computational framework are
based carrying out density functional theory within the Keldysh nonequilibrium Green's function
formalism. We analyze which molecular vibrational modes are most relevant to charge transport
under nonequilibrium conditions. For a molecular tunnel junction of a 1,4-benzenedithiolate
molecule contacted by two leads, the low-lying modes of the vibration are found to be most
important. As a function of bias voltage, the electron-phonon coupling strength can change
drastically while the vibrational spectrum changes at a few percent level.
10-18
Spin-polarized Injection and Transport in a Schottky Diode
M. SHEN, S. Saikin and M.-C. Cheng, Center for Quantum Device Technology, Department of
Physics and Department of Electrical and Computer Engineering, Clarkson University, Potsdam,
NY, shenm@clarkson.edu
Using the Monte Carlo simulation model, we studied spin polarized injection and transport in an
Fe(100)/GaAs(100) Schottky diode. Both intra-valley and inter-valley scatterings are considered.
The model accounts for electron spin dynamics in the Γ and L valleys. It is found that the upper
(L) valleys play an important role in spin transport close to the Schottky barrier. The simulation
results are consistent with experimental data.
10-19
Indirect Interaction of Localized Magnetic Moments in Luttinger Liquids
D. Mozyrsky1, A. DEMENTSOV2, D. Tolkunov2, 1Los Alamos National Laboratory, Los
Alamos, NM 87545, 2Center for Quantum Device Technology, Department of Physics, Clarkson
University, Potsdam, NY, dementav@clarkson.edu
Indirect interaction between localized spins in Luttinger liquid is investigated. We show that
spin-spin interaction is an oscillatory function of distance between localized spins (x ) with
amplitude decaying asymptotically as x  (1 g C ) / 2 where g C  1 for attractive and g C  1 for
repulsive interactions. We also derive effective dynamics for the system of two spins indirectly
coupled via Luttinger liquid in nonequlibrium regime.
11-01
Ionic Liquid Emulsions Stabilised Solely by Nanoparticles
B.P. BINKS, A.K.F. Dyab, P.D.I. Fletcher, Surfactant & Colloid Group, Department of
Chemistry, University of Hull, Hull, United Kingdom, P.D.Fletcher@hull.ac.uk
When colloidal particles are partially wetted by both oil and water they adsorb very strongly to
the oil-water interface and can serve as excellent emulsion stabilisers. The emulsion type, i.e.
water-continuous or oil-continuous and the emulsion stability can be tuned by control of the
particle surface’s affinity for the two solvents which can be expressed in terms of the contact
angle between the oil-water interface and the particle surface. In this presentation, we describe
the formation of both simple and multiple emulsions containing an ionic liquid with either water,
an oil or both stabilised solely by silica nanoparticles. We show how emulsion type and stability
can be optimised and emulsion phase inversion can be effected by varying the surface coating of
the silica nanoparticles. Using different combinations of mutually immiscible mixtures of water,
an ionic liquid and an oil we have successfully prepared many different types of simple and
multiple emulsions (e.g. “water-in-ionic liquid-in-oil”) which show excellent stability. The
emulsion results are correlated with liquid-liquid contact angle measurements on coated silica
surfaces.
11-02
Molecularly-Engineered Nanoparticles and Assemblies for Analytical/Bioanalytical
Applications
C. J. ZHONG, Jin Luo, Mathew Maye, Stephanie I-Im Lim, Lingyan Wang, Nancy Kariuki,
Peter Njoki, Mark Schadt, Derrick Mott, Elizabeth Crew, Yan Lin, Department of Chemistry,
State University of New York at Binghamton, Binghamton, NY, cjzhong@binghamton.edu
We have been exploring a general bottom-up pathway towards processing and assembling metal
and alloy nanoparticles for analytical/bioanalytical applications.
This pathway entails
molecularly-engineered processing of particle size, shape, composition and surface properties
and molecularly-mediated assembly via fine-tunable interparticle interactions including van der
Waals forces, covalent bonding, hydrogen-bonding, or ligand coordination. The advanced
materials present new opportunities in a wide range of technological applications, including fuel
cell catalysis, chemical or biological sensing, and medical diagnostics or treatments. The unique
electronic, interparticle spacing, chemical specificity, framework binding, molecular channeling,
and catalytic properties of the nanostructured materials provide fine-tunable chemical/biological
sensing interfaces. Recent results of our investigations will be discussed.
11-03
Some Phase Diagrams of Fruit Acids and the Consequences in their Application for Skin
Lotions
ABEER AL BAWAB, Chemistry Department, Faculty of Science, University of Jordan, Amman
11942, Jordan
The difference from a formulation point of view between a di-carboxylic acid and its two related
hydroxy acids with one and two hydroxy groups was investigated by comparing the structure of
their emulsions with a simple non-ionic surfactant as stabilizer and the changes taking place
during evaporation.
The results showed the introduction of a hydroxy group into the structures to have a radical
impact on the structure of the emulsion and, especially the changes during evaporation.
An evaluation of the volume fraction of vesicles in the emulsion showed these to occupy a larger
volume than is intuitively assumed.
The phase diagrams were determined of lactic and isohexanoic hydroxy- acids as well as
salicylic acid with water, a nonionic surfactant and a paraffinic oil to outline the influence of the
hydroxy-acids on the structure in a model for a skin lotion.
The results showed the influence of the acid to be similar to that of the oil, but that the difference
in chain length between the two alpha acids had only insignificant influence.
The results are discussed from two aspects; the structures involved in the lotion as applied
and the action of the lotion residue on the skin after the evaporation of the water
11-04
A Novel Method for the Computer Simulation of Surfactant Self-Assembly
H. SHINTO, S. Morisada, K. Higashitani, Department of Chemical Engineering, Kyoto
University, Kyoto, Japan, shinto@cheme.kyoto-u.ac.jp
With the help of increasing computational power, Molecular Dynamics (MD) and Monte Carlo
(MC) simulations are very useful for investigating the microscopic features of matter and
material. To investigate the molecular-level features of the surfactant solutions, several
researchers have implemented the MD and MC simulations of surfactant systems. However, it is
still difficult to simulate the self-assembly of surfactants using the atomistic models, because
long-time simulations of the large-scale systems are required to examine the surfactant selfassembly. A common alternative is the use of coarse-grained models to mimic the
oil/water/surfactant systems. The coarse-grained model simulations, however, provide only the
qualitative results, which are sufficiently suggestive but are not quantitatively comparable with
the experimental results.
In this talk, we present an implicit solvent model for the simulation of surfactant molecules in
aqueous solutions, where no water molecules of the solvent are treated explicitly, but the effects
are incorporated using the solvent-averaged interactions between the surfactant segments in
water. This model has been applied to the MD simulations of (i) the self-assembly of ndecyltrimethylammonium chloride surfactants at different concentrations and (ii) the single
micelles of different sizes. The results will be compared with those from experiments and
atomistic model simulations.
11-05
Transformation of Organized Assemblies in Surfactant Solutions
J. B. HUANG, College of Chemistry, Peking University, Beijing 100871, P. R. China,
JBHuang@.pku.edu.cn
By the variation of molecular structure and physichemical conditions, the formation and
transformation of amphiphilic molecular organized assemblies such as: micelle, vesicle, were
studied.
Transition of surfactant aggregates by adding non-polar organic compounds was investigated in
the cationic-anionic surfactant systems. The two-phase systems were transformed into
homogenous solutions with the octane addition. The results of DLS demonstrate the decrease of
vesicles and the increase of spherical micelles upon octane addition. Such transformation of the
surfactant aggregates was also corroborated by the results of time-resolved fluorescence
quenching and viscometry.
Surfactant aggregates were also studied in the mixed systems bolaform amphiphiles and opposite
charged conventional surfactant. Superior high temperature stability of vesicles was found in
some mixed systems. DSC, VT-IR and Fluorescence probe results all revealed that vesicles in
C20Na2/DEAB mixed systems can keep stable even at 80.
Temperature-induced micelle—vesicle transformation was also found in the mixed cationicanionic surfactant systems. Cylindrical micelle to vesicle transition upon the increase of
temperature was demonstrated in the system of SDS/DEAB. Notable transition occurred during
30-50oC and such transition was remarkably influenced by surfactant mixing molar ratio and
total surfactant concentration.
11-06
Thermodynamics and Dynamics of Diblock Copolymers at Polymer/Polymer Interfaces
B. J. Reynolds, M. L. Ruegg, N. P. Balsara, C.J. RADKE, Department of Chemical Engineering,
University of Californai, Berkeley, CA, radke@cchem.berkeley.edu
The efficacy of diblock copolymers for stabilizing interfaces between immiscible polymers
depends on both thermodynamic and dynamic factors. We study the equilibrium and dynamic
concentration profiles of an AB diblock co-polymer (i.e., the surfactant) at an A polymer/ B
polymer interface. We create thin polymer films containing two surfactant-bearing polymeric
interfaces and follow the transient concentration profiles of the diblock copolymer by dynamic
secondary-ion mass spectroscopy (SIMS). For well-equilibrated films, the measured
concentration profiles and the adsorption isotherms are in good agreement with self-consistent
field theory (SCFT), where all necessary parameters were determined independently from SANS
and gel-permeation-chromatography measurements. For the nonequilibrated films, transport of
the diblock copolymer depends on the two binary Fickian diffusion coefficients and on the depth
of the thermodynamic potential wells that hold the surfactant molecules at the interface.
Diffusion coefficients of our system were measured in independent SIMS experiments. We again
find excellent agreement between the measured transport rates of the AB surfactant across the
film interfaces and those calculated using a SCFT free-energy profile and diffusion in a potential
field. Fascinatingly, no kinetic barriers to adsorption/desorption are found. For the first time,
surfactant adsorption dynamics at a polymer/polymer interface is addressed.
11-7
The Linker Effect in Microemulsion Systems
EDGAR J. ACOSTA1, David A. Sabatini2, Jeffrey H. Harwell3, 1University of Toronto,
Department of Chemical Engineering and Applied Chemistry. 200 College Street room 131,
Toronto, ON, Canada, 2University of Oklahoma, Department of Civil Engineering and
Environmental Science. 202 W. Boyd, room 334, Norman, OK, 3University of Oklahoma,
Department of Chemical Engineering. 202 W. Boyd, room 107, Norman, OK
The surfactant-water and surfactant-oil interactions control the overall thermodynamic
equilibrium of microemulsion systems. Intuitively, by enhancing these molecular interactions,
more oil and water can be co-solubilized in microemulsion systems. One way to enhance these
interactions is by introducing lipophilic and hydrophilic linkers in the formulation. Lipophilic
linkers such as long chain alcohols (with more than eight carbons), fatty acids, and low HLB
non-ionic surfactants tend to segregate near the tails of the surfactants, serving as an extension of
these molecules into the oil phase. Hydrophilic linkers, on the other hand, are surfactant-like
molecules with short hydrophobe (between six to nine carbons) that co-adsorb at the oil/water
interface, increasing the interfacial area. The combination of lipophilic and hydrophilic linkers
produce self-assembled pseudo-surfactants at the interface that produce efficient microemulsions
with a wide range of oils, without using toxic medium chain alcohols, or high electrolyte
concentrations. The use of linker formulations in cleaning applications, environmental
remediation, and drug delivery systems will be discussed. The partition / segregation of linkers
will be discussed using the “zipper” self-assembly hypothesis that has been proposed to explain
the combined linker effect.
11-08
Experimental Observations of Dynamic Surface Tension atHighly Curved Microfluidic
Interfaces
HANS C. MAYER, Shelley L. Anna, Department of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, PA
In microfluidic devices, interfaces between two liquid phases are constrained by system
geometry to have high curvature. Recent scaling arguments report a new timescale relevant to
curved interfaces and predict a shift in the mechanism of surfactant mass transport from diffusion
controlled to kinetic controlled based on geometry alone. We have developed a microtensiometer
to measure the dynamic surface tension using a highly curved interface formed at the tip of a
glass micropipette, immersed in a reservoir of surfactant solution. We show microtensiometer
measurements for air-liquid interfaces using aqueous solutions of well characterized polyethoxylated surfactants. Our data indicate that the dynamic surface tension equilibrates earlier at
more highly curved interfaces, validating the prediction of a shift at microfluidic length scales.
Characterizing the dynamics of surfactants at microfluidic length scales will enable better control
over the deformation and breakup of drops in microfluidic devices as well as a greater
understanding of the role of surfactants in these dynamical processes.
11-09
Processing of Phospholipid Vesicles Using Supercritical and Compressed Fluids
G.D. Bothun, BARBARA KNUTSON, Department of Chemical and Materials Engineering,
University of Kentucky, 177 Anderson Hall, Lexington, KY, bknutson@engr.uky.edu
Emerging applications of supercritical fluids to bioprocessing exploit the interaction of CO2 with
phospholipid vesicles. This work examines the influence of CO2 on the bilayer fluidity of
liposomes, which are representative of model cellular membranes, at the elevated pressures (up
to 13.9 MPa) associated with CO2-based processing of liposomes and microbial sterilization.
Fluidization of aqueous dipalmitoylphosphatidylcholine (DPPC) liposomes by pressurized CO 2
(present as an excess phase) was studied by steady-state fluorescence anisotropy using the
membrane probe 1,6-diphenyl-1,3,5-hexatriene (DPH). Reversible, pressure-dependent
fluidization of the phospholipid vesicles was observed in both the gel and fluid phase states of
the DPPC bilayer (DPPC, Tm ~ 315 K). These experiments demonstrated substantial melting
point depression (ΔTm = -4.8 to -18.5 K) and a large broadening of the gel-fluid phase transition
region, which was interpreted using conventional theories of melting point depression. The
pressure-dependent surface activity of the of aqueous DPPC liposomes at the CO2 interface was
determined using high pressure interfacial tension measurements. This technique provided
complementary information on the influence of the CO2 interface on the adsorption and
disruption of phospholipids vesicles.
11-10
Synergistic Interactions Between Linear Polyethylene Oxide Surfactants and the Effect on
Surface Tension, Phase Behavior and Wetting
MAKONNEN M. PAYNE, Alexander Couzis, Charles Maldarelli, Department of Chemical
Engineering Graduate Center – CUNY, The City College of New York, Convent Avenue at 138th
Street; New York, NY, payne@che-mail.engr.ccny.cuny.edu
In this paper we report findings in synergistic interactions with respect to air-liquid interfacial
tension reduction, lyotropic phase behavior and wetting. We have previously reported that
combinations of 1-dodecanol with the polyethyleneglycol n-alkyl ether surfactants are able to
reduce the air-liquid interfacial tension to values on the order of 20 mN/m when the total
surfactant loading is on the order of 0.05% by weight. The mechanism for such significant
interfacial tension reduction is not yet completely understood, but we have been able to draw
correlations between the tension reduction and the presence of lyotropic phase, in the surfactant
solution. In order to gain insight as to what surfactant aggregate structures exist in our mixtures,
we employ cross-polarized microscopy and depolarized light scattering, where anisotropy of the
aggregated structures gives rise to characteristic patterns that can be observed using a digital
camera. We also report here, the ability for some of these surfactant systems to wet a model
hydrophobic surface and offer possible implications that can be made about the role of the
lyotropic phases and wetting. The model hydrophobic surface used is an octadecyltrichlorosilane
self-assembled monolayer on bare silicon.
11-11
On the Self Assembly of Asphaltenes to Form Nanoscale Aggregates
KEITH L. GAWRYS*, Vinnie Verruto#, Peter K. Kilpatrick#, *Nalco Company, Energy
Services Division, 7705 Highway 90-A, Sugarland, TX, #Department of Chemical and
Biomolecular Engineering, NC State University, Raleigh, NC, peter-k@ncsu.edu
Asphaltenes are the n-heptane insoluble and toluene soluble fraction of petroleum fluids. This
solubility definition leads to a heterodisperse mixture of molecules that contain fused aromatic
rings, a significant percentage of N, S, O heteroatoms (2-10%, w/w), and an aliphatic periphery
and aliphatic connectors of aromatic moieties. This unusual molecular architecture leads to the
characteristic colloid-forming properties of asphaltenes: colloidal instability during pressure and
temperature reductions, deposition during transportation and processing, self assembly in
solution, and adsorption onto solid-liquid, liquid-liquid, and liquid-vapor interfaces. Here, we
report a comprehensive study of the self assembly properties of asphaltenes, primarily as probed
by small angle neutron scattering (SANS) in organic solutions of heptane, toluene, methyl
naphthalene, methanol, and their mixtures. We have systematically explored the fitting of a
variety of geometric form factor models to our data and concluded that an oblate cylindrical
model with polydispersity in the radial dimension best fits a large dataset of independent
experiments. Such a fit, which agrees well with unbiased Guinier analyses of radii of gyration
and data extrapolation to obtain zero-Q scattering intensities, enables the evaluation of mean
aggregate volume and moments of the aggregate volume distribution. This in turn enables a
number of very important conclusions to be drawn about the physical properties of asphaltenic
aggregates. First, it is clear from our analysis that asphaltenes entrain a significant fraction of
solvent, as much as 50% (v/v), within the interior of the aggregates. Second, this entrained
solvent appears to rapidly exchange with solvent in the bulk. Third, the apparent fractal
dimension of these aggregates varies over a broad range from 2.2-3.0 and would seem to suggest
that asphaltenic aggregates, at least in the nanoscale range (1 nm < Rg < 15 nm), would seem to
be better characterized as globular aggregates with roughened surfaces, rather than as mass
fractals as many investigators have suggested. We have also been able to probe the flocculation
of nanoscale aggregates into larger microscale aggregates. Finally, we report on the interactions
of these nanoscale aggregates with each other by evaluating second virial coefficients and by
exploring the role of selective solvating agents, such as resins, acids, and polymeric additives.
11-12
Interfacial Alignment of Micelles in Surfactant-silica Aggregates as a General Approach to
Materials with Oriented Mesopores
B. Tan, S. E. RANKIN, Chemical and Materials Engineering Department, University of
Kentucky, Lexington, KY, srankin@engr.uky.edu
When silica and a cationic surfactant are precipitated from an ethanol/water/ammonia solution,
nearly monodisperse spherical particles with uniform, radially oriented channels result. This
structure is ideal for catalysis, adsorption, and chromatrography because it combines low
tortuosity with high accessibility. We investigate the formation mechanism of this structure
during precipitation of tetraethoxysilane with CTAB. Using TEM to observe samples extracted
early in the process and rapidly cooled, thinned and dried, we show that small disordered CTABsilica aggregates initially form. These aggregate into large spheres, and then CTAB micelles
elongate and orient normal to the particle interface, even in arbitrarily shaped particles. The
micelles continuously rearrange normal to the particle interface even as the particles aggregate
and reorganize into spheres. This alignment implies that there is no preference for polar or
nonpolar parts of the silica-surfactant mesophase at the particle-solution interface. This
mechanism - precipitating soft silica-organic aggregates followed by nucleation of an ordered
structure - can be generalized to other surfactant-templated systems and possibly zeolites. For
instance, in layered particles formed using a cationic fluorinated surfactant, the particles elongate
perpendicular to the layers. This is consistent with silica-surfactant aggregates initially acting
like dispersed soft liquid crystals.
11-14
The Application of Surfactant Phase Behavior in Developing Oilfield Product
JIANG YANG, Valdimir Jovancicevic, Baker Petrolite, Sugar Land, TX
Phase behavior was very important for many areas of applications from drilling fluid to enhance
oil recovery in petroleum industry. Drag reducing surfactant was developed with studying the
phase behavior of the surfactants. The mixture of surfactants and co-surfactants reduce the gel
phase of hexagonal liquid crystal, and make faster transition to drag reducing wormlike micelle
phase during the dilution.
11-15
Origin of the Sphere-to-Rod Transition in Micellar Solutions: Specific Ion Hydration
Matters
Yan Geng, LAURENCE S. ROMSTED, Department of Chemistry and Chemical Biology,
Wright-Rieman Laboratories, Rutgers, The State University of New Jersey, New Brunswick, NJ,
romsted@rutchem.rutgers.edu
Understanding the relationships between surfactant structure and aggregate morphology should
permit “tuning” of bulk properties of soft materials, which have important applications as
thickeners, drag reducers, and hard surface cleaners. Micelle formation and the transition from
spherical to rodlike, wormlike and threadlike micelles depend not only on surfactant tail
structure, but also surfactant headgroup structure and counterion type (e.g., Hofmeister series)
and concentration. However, the balance of forces determining such transitions are not fully
understood.
The chemical trapping method based on the heterolytic chemistry of arenediazonium ions is
providing new information on the concentrations of weakly basic nucleophiles such as water,
halide ions, alcohols and urea within the interfacial regions of association colloids. Recent results
show that of the 12-n-12 2Br (n = 2-4) series of gemini surfactants, only the gemini surfactant
with n = 2 shows a marked increase in interfacial Br– with a concomitant decrease in interfacial
water concentration with increasing surfactant concentration. Published cyro-TEM results show
that only 12-2-12 form rods under these conditions. This and other chemical trapping results
support a model in which sphere-to-rod transitions are governed by specific ion dependent
dehydration of interfacial head groups and counterions to form hydrated ion pairs.
11-16
DNA-copolymer Vesicles for Gene Delivery
A.V. Korobko1, C. Backendorf1, J. R. C. VAN DER MAAREL2, 1Leiden Institute of Chemistry,
Leiden University, P.O. Box 9502, 2300 RA Leiden, the Netherlands, 2National University of
Singapore, Department of Physics, 2 Science Drive 3, Singapore
We report the design, structural characterization, and transfection ability of cationic diblock
copolymer vesicles loaded with cloning vector DNA. Encapsulation was achieved with a single
emulsion technique. For this purpose, an aqueous plasmid solution is emulsified in an organic
solvent and stabilized by an amphiphilic diblock copolymer. The neutral block forms an
interfacial brush, whereas the cationic attachment complexes with DNA. A subsequent change of
the quality of the organic solvent results in the collapse of the brush and the formation of a
capsule. The capsules are subsequently dispersed in aqueous medium to form vesicles and
stabilized with an osmotic agent in the external phase. Inside the vesicles, the plasmid is
compacted in a liquid-crystalline fashion as shown by the appearance of birefringent textures
under crossed polarizers and the increase in fluorescence intensity of labeled DNA. The
compaction efficiency and the size distribution of the vesicles were determined by light and
scanning electron microscopy, and the integrity of the DNA after encapsulation and subsequent
release was confirmed by gel electrophoresis. We demonstrate the gene transfer ability of this
new model carrier system by the transfection of encapsulated pEGFP-N1 plasmid into HeLa
cancer cells through the fluorescence of the expressed GFP protein.
11-17
Controlled Synthesis and Hierarchical Assembly of One-Dimensional Inorganic
Nanostructures in Micellar Systems
LIMIN QI,* Hongtao Shi, Yurong Ma, Jiming Ma, State Key Laboratory for Structural
Chemistry of Unstable and Stable Species, College of Chemistry, Peking University, Beijing,
P.R. China, liminqi@pku.edu.cn
Both reverse and normal micelles are used as nanostructured media for synthesizing various onedimensional (1D) inorganic nanostructures such as nanowires, nanobelts, and nanotubes. Unique
catanionic reverse micelles formed by mixed cationic-anionic surfactants are employed for the
controlled synthesis and hierarchical assembly of 1D BaXO4 (X = Cr, Mo, W) nanostructures.
The effects of various factors, such as the mixing ratio between the anionic and cationic
surfactants, the temperature, and the polymeric additives, on the formation of 1D BaXO4
nanostructures and the architectural control of their complex superstructures are examined. A
plausible two-stage growth mechanism has been proposed for the formation of the penniform
BaXO4 nanowire/nanobelt superstructures. On the other hand, normal micelles of nonionic
surfactants are employed for the controlled synthesis of single-crystalline nanotubes, nanowires,
and nanobelts of trigonal selenium (t-Se). In particular, well-defined t-Se nanotubes are
fabricated in micellar solutions of the nonionic surfactant C12EO23. It is revealed that the
nonionic micelles play an important role in controlling the distribution and diffusion of
amorphous Se in the solution and hence exert delicate control over the morphology of the 1D tSe nanostructures. These results demonstrate the great potential of micellar systems in
synthesizing and assembling 1D nanostructures in solution.
11-18
Droplet Breakup in Shear and Elongation Dominated Flows in Microfluidic Devices
A. J. Greiner, J. A. Taylor, G. F. Christopher, S. L. ANNA, Department of Mechanical
Engineering, Carnegie Mellon University, Pittsburgh, PA, sanna@cmu.edu
Microfluidic devices have recently been demonstrated as an effective platform for generating
monodisperse drops and bubbles on a drop-by-drop basis. Precise control over droplet size has
the potential to impact a wide range of applications from emulsification to drug delivery and lab
on a chip. In this talk we compare drop formation mechanisms in microfluidic devices in which
flows can be either predominantly shear flows, or predominantly elongational flows. In either
case, drops of an aqueous liquid form due to viscous stresses imposed by a second oil phase.
However, we show that the two different flow types lead to dramatically different ability to
control droplet sizes. We characterize the drop formation mechanism and the resulting drop size
over a large number of experiments by varying capillary number, volume fraction, and viscosity
ratio. We observe several distinct modes of breakup that depend on these three dimensionless
parameters, as well as the flow type and microfluidic design.
11-19
Sulfolane Microemulsions as Possible Inert Reaction Media
THOMAS WIELPÜTZ, Thomas Sottmann and Reinhard Strey, Institute for Physical Chemistry,
University Cologne, D-50939 Cologne, Germany, twielpuetz@uni-koeln.de, tsottma@unikoeln.de, rstrey@uni-koeln.de
Very recently, it turned out that nano-structured reaction media containing highly inert solvents
as tetrahydrothiophen-1,1-dioxid (sulfolane) are needed in strongly oxidizing or reductive
reactions. Due to their ability of solubilizing polar and nonpolar solvents with a large nanostructured interface in particular microemulsions provide such interesting reaction media.
Starting from the pseudo-ternary microemulsion H2O-n-octane-C12E4/C12E5 (polyoxyethylene
n-alkylether) water was successively replaced by the highly inert tetrahydrothiophen-1,1-dioxid
(sulfolane). It is found that an increasing sulfolane content drives the system beyond the
tricritical point. Replacing the already long chain surfactants C12E4 and C12E5 by a mixture of the
really long chain surfactants C18E6 and C18E8 a sulfolane-microemulsion was prepared for the
first time. In a second step the phase behavior of the hydrophilic sulfolane - n-octane -C18E8
system was tuned at constant temperature (reaction condition) by adding the hydrophobic
cosurfactant 1-octanol. Thereby, the size of reverse micelles were investigated by DLS
exhibiting radii varying from at least 8 nm to 20 nm.
11-20
Stabilization of Water-in-Oil Emulsions by Silica Nanoparticles and Surfactant
B.P. BINKS, J. Philip, Surfactant & Colloid Group, Department of Chemistry, University of
Hull, Hull,United Kingdom, j.philip@hull.ac.uk
Emulsions are metastable due to the excess energy associated with the large interfacial area.
Electrostatic stabilization by surfactants and steric stabilization by macromolecules are quite well
understood and the focus is now on solid particle- stabilized systems. Some of the unanswered
issues in the area of mixed particle-surfactant systems are the following: What happens when
solid nanoparticles and surface-active molecules are used in water-in-oil emulsions? Do particles
or surfactant or both go to the interface or is there a preference for one to be at the interface over
the other? What happens if solid particles and surfactant form complexes in bulk or at the
interface? Do particles and surfactant act synergistically to enhance the long term stability of the
emulsions? What are the implications of complexation on the rheology of the emulsion? In this
paper, we answer these intriguing questions from systematic studies using water-in-silicone oil
emulsions prepared with silica nanoparticles and a polymeric surfactant. These emulsions are
characterised by light scattering, optical microscopy, freeze fracture electron microscopy and
rheology.
11-21
Photo-Surfactants
J. EASTOE1,M. Sanchez Dominguez1, P. Wyatt1, A. Beeby2, R. K Heenan3, 1School of
Chemistry, University of Bristol, Bristol, United Kingdom., 2Department of Chemistry,
University of Durham, South Road, Durham, United Kingdom, 3ISIS-CLRC, Rutherford
Appleton Laboratory, Chilton, Oxon, United Kingdom, julian.eastoe@bristol.ac.uk
For surfactants containing a suitable chromophore, light can be used to trigger changes in
aggregation and adsorption. The advantage of this approach is it eliminates, or minimizes, the
need for composition or temperature changes. New photosurfactants have been synthesized, and
photoreactions in water, water-in-oil microemulsions, interfacial properties and changes in
aggregation characterized [1]. As such changes in activity under wide range of colloidally
relevant situations has been demonstrated: airwater, oil-water and solid-liquid interfaces, as well
as aggregation in aqueous and microemulsion dispersions. These results highlight the importance
of molecular design for generating effective and efficient photosurfactants.
11-22
Controlled Polymerization of Acrylates by Macromolecular Design via Interchange of
Xanthates in Microemulsions
JENNIFER O’DONNELL, Eric W. Kaler, Department of Chemical Engineering, University of
Delaware, Newark, DE, odonnejm@che.udel.edu
The ability to produce stable latex nanoparticles of monodisperse polymer chains is desired for
many applications. Reversible addition-fragmentation chain transfer (RAFT) has proven to be a
successful method of controlled polymerization for many monomers and reaction conditions.
However, the polymerization mechanism is not well understood. Implementing RAFT in
microemulsion polymerization provides a model system in which to study the RAFT mechanism
because microemulsion polymerization eliminates biradical termination by segregating the
propagating polymer chains into surfactant stabilized polymer particles.
In this work we have implemented the RAFT process of Macromolecular Design via Interchange
of Xanthates (MADIX) in the microemulsion polymerizations of butyl acrylate and 2-ethylhexyl
acrylate. The kinetic rates, polymer molecular weights and latex particle sizes have been
measured for several MADIX agent to micelle ratios at two initiator concentrations. The results
of these experiments provide insight into the mechanism of RAFT polymerizations.
11-23
Ultrasound for Characterizing Soft colloids
A. DUKHIN, P. Goetz Dispersion Technology Inc., 364 Adams Street, Bedford Hills, NY
We present experimental data and its interpretation regarding characterization of various
emulsions, mini- and micro-emulsions using ultrasound. Characterization includes droplet size
distribution and -potential for both, water-in-oil and oil-in-water systems. This characterization
allowed us to establish a link between electric properties and evolution of these systems.
11-24
Flow-induced Phenomena in Solutions of Wormlike Micelles
Matthew Liberatore, Florian Nettesheim, Eric Kaler, NORMAN WAGNER, University of
Delaware, Newark, DE
Surfactant molecules in solution can self-assemble into wormlike micelles. Micellar solutions are
common in the cosmetic, detergent and food industries. Solutions of these wormlike micelles
have behavior similar to that of polymers, but are also able to reversibly break and recombine.
Current work probing two viscoelastic micellar solutions of identical surfactant concentration
has found the concentration of incorporated salt to critically influence solution behavior. While
the two samples are quite similar in viscosity across a range of shear rates, only one sample
exhibits shear-induced phase separation (SIPS). The important length scales of the two micellar
networks are investigated via dynamic rheology, rheo-optics and small-angle neutron scattering
(SANS). The mesh size and entanglement length of the micelles that exhibit SIPS are smaller
than the other sample. Therefore, the solution that phase separates under flow forms a more
densely entangled network. Additional investigation into the nonlinear rheology of these
samples is completed using particle tracking velocimetry (PTV) and flow-SANS in the 1-2 plane.
PTV finds shear banding for the sample exhibiting SIPS while the other sample behaves like a
power law fluid. The appearance and growth of the shear bands for the sample exhibiting SIPS
will be explored in detail.
11-25
Effect of Oil on Emulsion Characteristics: Manipulating the Interfacial Domain
H. EGGER1, E.-H. Liu2, K. M. McGrath1, 1School of Chemical and Physical Sciences, Victoria
University of Wellington, P.O. Box 600, Wellington, New Zealand, 2Department of Chemistry,
University of Otago, P.O. Box 56, Dunedin, New Zealand, holger.egger@vuw.ac.nz
The ternary systems (water, triton X-100 and n-alkane) were investigated using freezefracture
TEM, rheology, laser diffraction particle sizing, and PFG-NMR. The stability of the oil-in- ater
dispersed droplet emulsions significantly increased with both the surfactant concentration and
the chain length of the oil component. The PFG-NMR experiments monitored a superposition of
the restricted diffusion of the oil in the droplets and free and restricted diffusion of the droplets
themselves, and were correlated with the TEM images and the particle sizing data. Moreover, the
present investigations were compared with earlier investigations where toluene was used as the
oil. The change from the aromatic oil to an alkane-based oil dramatically changed the
characteristics of the interfacial domain. The concentration range for the formation of emulsions
and the variety of microstructures realized were severely restricted, but the interfacial film was
much more stable leading to an extremely reduced rate of droplet coalescence. Additionally,
concerning the destabilisation mechanisms, the alkane systems followed a much more
complicated process compared with the toluene system. It was found that the principal
destabilisation process was the same for all alkanes, whereupon the time constant of this process
can be adjusted by using the appropriate chain length of the oil.
11-27
Liquid Crystalline Silicate/Surfactant Mesophase in Nanoscale Confinement
DONGHAI WANG, Rong Kou, Yunfeng Lu, Department of Chemical & Biomolecular
Engineering, Tulane University, New Orleans, LA, ylu@tulane.edu
Cooperative assembly of silicate/surfactant replicates liquid crystalline mesophase of surfactant
resulting in highly ordered mesostructures of inorganic/organic composite (e.g. cubic, hexagonal,
lamellar structure). The self-assembly process can be altered readily by interfacial, geometric
and other boundary conditions due to its weak non-covalent driving forces. In this presentation,
we will show self-assembly behavior of liquid crystalline silicate/surfactant mesophase within
nanoscale cylindrical pores of anodized alumina membranes. Morphology of the liquid
crystalline silicate/surfactant composite was studied using XRD, TEM and SEM. We observed
the transition from hexagonal to lamellar mesostructure of the liquid crystalline mesophase
within the nanoscale confinement when surfactant concentration is increased. The hexagonal
silicate/surfactant mesophase in nanoscale cylindrical pores prefers to orient along long axis of
alumina pores, which is distinct from circular hexagonal mesostructure prepared by evaporation
induced self-assembly process[1]. Lamellar silicate/surfactant layers grow along curved pore wall
surface resulting in oriented concentric lamellar mesophase. The corresponding mesoporous
silica wires with oriented hexagonal tubular and concentric lamellar pore channels were obtained
after removal of surfactants. The novel structured mesophase and corresponding mesoporous
silica/alumina composite are expected in membrane based application such as separation,
templating synthesis, etc. This work also will bring the insight of nanoscale confiment effect on
self-assembly process.
11-28
Microstructure of Bicontinuous Nanoporous Materials Prepared from Methyl
Methacrylate/Hydroxyethyl Methacrylate Microemulsions Formulated with Biocompatible
Surfactant
F. Ye, R.T. Vickerman, S. Lopina, H. M. CHEUNG, E. von Meerwall, Department of Chemical
Engineering and Department of Chemistry, Physics and Polymer Science, University of Akron,
Akron, OH, fy2@uakron.edu
The biocompatible surfactant Ryoto Sugar L-1695 stabilizes transparent microemulsion
precursors from the monomers of methyl methacrylate (MMA) and hydroxyethyl methacrylate
(HEMA). Polymerized bicontinuous microemulsions showed nanoporous structure under
scanning electronic microscopy (SEM). The pore size distribution of the polymeric materials was
determined from freezing point depression (PFD) of water which was characterized by two
different methods: differential scanning calorimeter (DSC) and pulsed gradient spin-echo
(PGSE) NMR. Results from both DSC and PGSE-NMR indicated that the aqueous content in
microemulsion precursor influenced the microstructure of the polymer formed whereby.
Increased pore size was observed when increasing aqueous content.
11-29
Transition from Unilamellar to Bilamellar Vesicles Upon the Addition of an Associating
Biopolymer
Jae-Ho Lee1, Gregory F. Payne2, Vivek Agarwal3, Arijit Bose3, SRINIVASA R. RAGHAVAN1,
1
Department of Chemical Engineering, University of Maryland, College Park, MD, 2Center for
Biosystems Research, University of Maryland Biotechnology Institute, College Park, MD,
3
Department of Chemical Engineering, University of Rhode Island, Kingston, RI,
sraghava@eng.umd.edu
The effect of adding a hydrophobically-modified chitosan to unilamellar surfactant vesicles is
studied using SANS and cryo-TEM. The hydrophobes on the polymer have a tendency to
become embedded in vesicle bilayers. This leads to changes in the size and ultimately in the
morphology of the vesicles. At low amounts, the addition of polymer decreases the unilamellar
vesicle size. At higher polymer concentrations, high-q peaks emerge in the SANS spectra which
imply the co-existence of multilamellar vesicles together with the unilamellar ones. Detailed
modeling of the SANS data suggests that most of the multilamellar vesicles have exactly two
concentric bilayers (i.e., they are bilamellar). This intriguing prediction is confirmed by cryoTEM images. The origin of the changes in vesicle morphology will be explored in this
presentation.
11-31
Synthesis and Chiral discrimination of Chiral Sensor with Self-Assembled Monolayers of
Functionalized  -Cyclodextrins
Siu-Choon Ng, WEI-GUANG ZHANG, Tong Sun, Chan-Ghua Xu, and Hardy S.O. Chan,
Department of Chemistry, National University of Singapore, Lower Kent Ridge Road,
Singapore, chmzwg@nus.edu.sg or chmcsoh@nus.edu.sg
Three chiral sensors were synthesised and studied by using a quartz crystal microbalance (QCM)
coated with self-assembled mercaptyl functionalized -cyclodextrin (-CD) derivatives. which
are (6A--mercapto-ethylureado-6A-deoxy)heptakis(2,3-di-O-benzoyl)-6B, 6C, 6D, 6E, 6F, 6Ghexa-O-benzoyl--cyclodextrin
(Ph--CDS),
(6A--mercapto-hexanureado-6Adeoxy)heptakis(2,3-di-O-benzoyl)-6B, 6C, 6D, 6E, 6F, 6G-hexa-O-benzoyl--cyclodextrin (Ph-CDM) and (6A--mercapto-undecanylureado-6A-deoxy)heptakis(2,3-di-O-benzoyl)-6B, 6C, 6D,
6E, 6F, 6G-hexa-O-benzoyl--cyclodextrin (Ph--CDL). The preferential binding of the chiral
analytes at these -CD monolayers in comparison with that on the reference coating suggested
the formation of inclusion complexes. Improved chiral discrimination was achieved by the -CD
monolayers modified QCM sensors in comparison with GC and HPLC separation performance.
Furthermore on-line dertermination of enantiomeric composition in the samples by these QCM
sensors was described. We also studied the specific host-guest interactions between enantiomeric
analytes and the self-assembled -CD monolayers on QCM under gaseous atmosphere and liquid
phase. Thermodynamic parameters about these chiral discriminatory processes were obtained in
gas and liquid phase from the linear curves of temperature-dependant chiral discrimination
factors of the three -CD monolayers, which revealed the existence of excellent compensatory
enantioselective enthalpy-entropy relationship from the linear curve of R,SH vs.
12-01
The Rheology of Anisometric Particle Dispersions and "Liquid Armor"
NORMAN J. WAGNER, Center for Molecular & Engineering Thermodynamics, Dept. of
Chemical Engineering, University of Delaware, Newark, DE
Novel ballistic resistant composite materials are formulated from colloidal dispersions of
anisometric particles. Through ballistic testing, the mechanism of energy adsorption at ballistic
rates is demonstrated to result from reversible shear thickening in the colloidal dispersion. As a
basis for the rational design of ballistic resistant materials, we report a rheological and
microstructural investigation of dispersions of stabilized, acicular precipitated calcium carbonate
(PCC) particles of varying aspect ratio. The effects of particle shape on the low shear viscosity,
shear thinning behavior, and onset of shear thickening is explored. Rheology-Small Angle
Neutron Scattering studies (RHEO-SANS) demonstrate particle alignment with the flow and
debunks previously hypothesized mechanisms for shear thickening in anisometric particles. The
experimental results demonstrate that increasing particle aspect ratio leads to enhanced shear
thickening at much lower particle concentrations than observed in comparable suspensions of
spherical colloidal particles. These results are predicted by micromechanical models to elucidate
the mechanism of shear thickening in suspensions of anisotropic particles. The application of
these dispersions in formulating novel energy absorbing materials is discussed.
12-02
Rheological Behavior of Bauxite Residue and Bauxite Residue Derivatives
E. M. HUMISTON, G. Ahmadi, G. Campbell, Clarkson University, Potsdam, NY,
notoem@clarkson.edu
Over 70 million metric tonnes of bauxite residue is produced annually as a by-product of
aluminum production. Currently the residue is being landfilled and will continue to be stored in
various locations requiring ongoing management because of the caustic nature of the residue.
The objective of this research is to provide an understanding of the rheological behavior of
bauxite residue and bauxite residue derivatives. Rheological measurements were carried out
using a rotational rheometer for shear rates between 0 and 400 s-1 in a range of pH values and
various solid concentrations. Two dissimilar shear-thinning regimes are evident within each data
set. As pH is reduced the corresponding viscosity curve is shifted to a lower viscosity. A
practical rheological model for bauxite residue including the effect of change in pH (via CO2 gas
diffusion), solids concentration, while monitoring particle size distribution is described. The
goal is to provide the aluminum industry with sufficient information to predict the flow behavior
of bauxite residue and bauxite residue derivatives so that engineering processes for their disposal
and/or conversion to commercial products can be designed.
12-03
Active and Nonlinear Microrheology
JOHN F. BRADY, Division of Chemistry and Chemical Engineering, California Institute of
Technology, Pasadena, CA
Over the last decade a set of experimental techniques collectively known as ‘microrheology’ has
emerged as an alternative to traditional ‘macrorheology’, with the ability to probe the
viscoelastic properties of soft heterogeneous materials (e.g. polymer solutions, colloidal
dispersions, biomaterials, etc.) at the micrometer (and smaller) scale. In microrheology, elastic
and viscous moduli are obtained from measurements of the fluctuating thermal motion of
embedded colloidal probes. In such experiments, the probe motion is passive and reflects the
near-equilibrium (linear response) properties of the surrounding medium. By actively pulling the
probe through the material, further information about nonlinear material properties can be
obtained, analogous to large amplitude measurements in macrorheology. We consider a simple
model of such systems: a colloidal probe pulled through a suspension of neutrally buoyant bath
colloids. The non-equilibrium spatio-temporal configuration or microstructure of particles
induced by the motion of the probe is calculated analytically and via Brownian Dynamics
simulations and used to infer the dispersion's 'effective microviscosity'. The computed effective
viscosities compare well with analogous macrorheology studies of sheared colloidal dispersions,
suggesting that active tracking microrheology can be a valuable tool with which to explore the
rich nonlinear behavior of complex materials.
12-04
Microrheology of a Colloidal Suspension Using Laser Tweezers
A. MEYER, M. H. Lee, E. M. Furst, Department of Chemical Engineering, University of
Delaware, Newark, DE
The microrheology of a colloidal suspension is measured using laser tweezers and the structure is
visualized with confocal microscopy. Suspensions of index-matched silica and fluorinated
ethylene propylene (FEP) are seeded with index-mismatched melamine and polystyrene probe
particles, respectively. The probes are trapped with laser tweezers and subjected to a uniform
flow enabling measurements of the suspension microrheology. Good agreement is found
between the microviscosities of FEP measured with laser tweezers and bulk viscosities using a
couette cell. As the probe size approaches the suspension particle size, non-linear behavior
similar to shear thinning is observed at higher suspension concentrations. This is consistent with
the formation of a ``wake'' in the non-equilibrium pair distribution function between the probe
and bath particles [Squires and Brady, 2005], which is demonstrated by confocal images of probe
experiments in fluorescent silica suspensions.
12-05
Rheological Behavior of Nano-Dendrimers / Silica Suspensions
GANG LI, Stanley Hirschi, Leela Rakesh, James Falender, Chemistry, Physics, & Mathematics
Departments, Central Michigan University, Mount Pleasant, MI
The electrorheological behavior of dendrimers/silica/silicone oil suspensions has been
investigated. A surprisingly strong correlation of the electrorheological response with the level of
maximum shear stress during steady flow measurements has been noted. The experimental
results may be explained by polar or polarizable particles lining up in an external electric field.
The drive toward alignment must overpower the Brownian motion and/or mechanical
perturbation. Dielectric properties of the suspended particles will favor alignment – but the
resistivity of the suspended particles must be high enough to avoid excessive current flow.
12-06
Melting in Temperature Sensitive Colloidal Suspensions
ARJUN G. YODH, Department of Physics & Astronomy, University of Pennsylvania,
Philadelphia, PA
I will talk about recent experiments from my lab wherein we use temperature-sensitive NIPA
polymer and NIPA microgel particles to drive melting transitions. In colloidal crystal
experiments we observe premelting at grain boundaries and dislocations. In colloidal rod
experiments we observe melting of lamellar phases into nematic phases.
12-07
The Effect of Nanoparticles on the Structure and Rheology of Clay Suspensions
J. BAIRD, J. Y. Walz, Department of Chemical Engineering, Yale University, New Haven, CT,
jason.baird@yale.edu
Suspensions of clay particles (kaolinite) combined with silica nanospheres undergo a dramatic
stabilization process, which increases suspension viscosity as well as elasticity to the point where
the suspensions can support their own mass as well as be sectioned. The suspensions develop a
significant yield stress, which can be overcome by vigorous shaking, making the process
completely reversible. These transitions are observed for kaolinite concentrations of 14 percent
by volume (v/o), and nanosphere concentrations as small as 3 percent. Decreasing the
nanosphere size at constant volume fraction results in higher yield stresses, significant elasticity,
and shorter time scales for gel development. SEM micrographs obtained by cryogenic fracturing
of the samples indicate that the added nanoparticles produce a more ordered, 'honeycomb-like'
structure, possibly arising from a very localized phase separation. In some of the nanoparticle
solutions, ordering of the clay platelets into dense stacks is also observed.
12-08
Evaporation-Induced Particle Microseparations inside Freely Floating Droplets
SUK TAI CHANG, Orlin D. Velev, Department of Chemical and Biomolecular Engineering,
North Carolina State University, Raleigh, NC, odvelev@unity.ncsu.edu
We study colloid particle transport inside single microdroplets of water floating on the surface of
inert fluorinated oil. This is done on a new type of microfluidic chips, where the droplets are
manipulated with alternating electric fields applied to arrays of electrodes below the oil. The
particles collect at the top region of the floating droplets and phase-separate in layers based on
their size and density. These remarkable microseparation processes can be used for on-chip
synthesis of advanced particles, microscale separations without other integrated components and
innovative microbioassays. We report experimental results and theoretical simulations that
explain the microsepration as a result of series of processes driven by mass and heat transfer.
During the evaporation, a surface tension gradient on top of the droplet occurs as a result of a
non-uniform temperature distribution. This interfacial tension gradient generates an internal
convective Marangoni flow. The colloidal particles transported by the convective flow collect on
the top of the droplets by the hydrodynamic flux compensating for the evaporation. The internal
flow pattern and temperature distribution within the evaporating droplet were simulated using
finite element calculations. The simulation was consistent with experiments using tracer
particles.
12-09
Mobility and In-situ Aggregation of Charged Microparticles at Oil-Water Interfaces
Sowmitri Tarimala, Chihyuan Wu, LENORE L. DAI, Department of Chemical Engineering,
Texas Tech University, MS 3121, Lubbock, TX
Particle mobility, aggregate structure, and the mechanism of aggregate growth at the twodimensional level have been of long-standing interest. Here we use Pickering emulsions as a
model system to investigate the mobility of charged microparticles at polydimethylsiloxane (oil)water interfaces using confocal laser scanning microscopy. Remarkably, the rate of diffusion of
the charged colloidal-sized polystyrene particles at the oil (5 cSt)-water interface is only
moderately slower than in the bulk water phase. The ambient diffusion constant of solid
particles is significantly reduced from 1.110-9 cm2/s to 2.110-11 cm2/s when the viscosity of the
oil phase increases from 5 cSt to 350 cSt. In addition, we have investigated the influences of
interfacial curvature and successfully observed the in-situ structural formation of solid particles
at the oil-water interface.
12-10
Crystalline Junctions in Associative Gels: PLA-PEO-PLA Triblocks with Tunable
Rheology
S. K. Agrawal1, N. Sanabria-DeLong2, G. N. Tew2, S. R. BHATIA1, 1Department of Chemical
Engineering and 2Department of Polymer Science and Engineering, University of Massachusetts
Amherst, Amherst, MA, sbhatia@ecs.umass.edu
Soft biomaterials derived from amphiphilic polymers have received considerable attention in the
last decade. The ability to tune the modulus of implantable materials to match that of native
tissue is crucial for scaffolding applications; unfortunately, a significant limitation of current
polymeric biomaterials is a lack of mechanical robustness and a low elastic modulus. We
address these issues using hydrogels of poly(lactic acid)-poly(ethylene oxide)-poly(lactic acid)
(PLA-PEO-PLA) triblock copolymers, which form associative network gels with the PLA
domains serving as network junctions. Our work distinguishes itself from previous studies
through controlled crystallinity of the junction points. We can create nanoscale crystalline
junctions through use of copolymers in which the PLA block is poly(L-lactic acid) (PLLA), or
amorphous junctions through copolymers in which the PLA blocks contain D-lactic acid and Llactic acid (PDLLA). The crystalline junctions in the PLLA-based gels cause a significant
increase in the elastic modulus over the PDLLA gels, allowing us to create biocompatible gels
with elastic moduli that are an order of magnitude higher than previously reported with
biocompatible associative gels. The modulus is also very sensitive to PLA block length and can
be easily tuned through to match the moduli of native tissue for a variety of applications. These
crystalline junction points may be considered a new mode of association in polymer gels and a
novel method for tuning the rheological properties.
12-11
Microstructural and Microrheological Properties of Novel Self-assembled Hydrogels
CECILE VEERMAN*, Karthikan Rajagopal#, Joel P. Schneider#, Eric M. Furst*, *Department
of Chemical Engineering, University of Delaware, Newark, DE, #Department of Chemistry and
Biochemistry, University of Delaware, Newark, DE
Hydrogels are an important class of materials that have extensive uses in tissue engineering and
drug delivery applications. Recently, a short 20 amino acid β-hairpin peptide has been designed
for the preparation of novel hydrogels, that reversibly folds and gel by a process of hierarchical
self-assembly. Little is known of the gelation kinetics and microstructure of these complex
materials. A better understanding on a microscopic level is necessary because we expect that for
these hydrogels the microscopic structure and heterogeneity will impact the cellular response to
the material. In this study the gelation kinetics and microstructure of the self-assembled
hydrogels was investigated with the use of multiple particle tracking. An increasing gelation time
with decreasing peptide concentration was found. The self-part of the van Hove correlation
function and a non-Gaussian parameter were used to obtain insight into the heterogeneity of the
microenvironment of the hydrogel. Microrheological techniques enable us to understand the
mechanical properties of hydrogels at a microscopic level, enabling the design of novel peptides
that will lead to the ultimate microstructural and microrheological properties necessary for tissue
engineering and drug delivery applications.
12-12
The Role of Bile Salt in Inducing Threadlike Reverse Micelles of Lecithin in Organic
Solvents
Shih-Huang Tung, Yi-En Huang, SRINIVASA R. RAGHAVAN, Department of Chemical
Engineering, University of Maryland, College Park, MD, sraghava@eng.umd.edu
Threadlike or wormlike micelles are formed by charged surfactants in water upon the addition of
salt. Here, we report a similar phenomenon in organic solvents, i.e., the formation of reverse
wormlike micelles by the phospholipid, lecithin upon the addition of a bile salt. Bile salts are
biological amphiphiles having a planar, “facially-amphiphilic” structure. Adding a few mM of
the bile salt, sodium deoxycholate (SDC) to a semidilute solution of lecithin in cyclohexane, is
enough to induce the growth of reverse micelles from spheres to long, cylindrical threads. In the
process, the sample is transformed from a low-viscosity fluid into a highly viscoelastic and flowbirefringent fluid. Similar results are observed in a range of nonpolar organic liquids. We will
present data from rheology and small-angle neutron scattering (SANS) on these micellar fluids.
A tentative model for the reverse micelle structure will be proposed in an attempt to clarify the
role played by the bile salt in inducing micellar growth.
12-13
Dynamics of Brownian particles in Concentrated Wormlike Micelle Solutions
FLORIAN NETTESHEIM, Matthew Liberatore, Eric W. Kaler, Norman J. Wagner, Department
of Chemical Engineering, University of Delaware, Newark, DE, netteshe@che.udel.edu
Brownian motion in complex fluids is of scientific interest as the particle motion couples to the
underlying dynamics of the suspending media, as well of industrial interest in the consumer
products, paints, detergents, and food industries for example, as such formulations often contain
colloids and emulsions. Brownian particles are also used as probes of local linear viscoelasticity
in complex fluids and biological materials, a technique known as micro-rheology. Here, we
investigate the Brownian motion of model colloidal particles dispersed in an entangled wormlike
micellar mesh and the associated mixture rheology and microstructure. This regime, where
particle size and relaxation times are comparable to the length and relaxation time scales of the
suspending medium, is poorly understood. Results of rheological investigations, small-angle
neutron scattering, and dynamic and static light scattering are reported. The properties of the
wormlike micellar solution and particles are systematically varied to explore the coupling
between particle and self-assembled aggregate dynamics and microstructure. Significant effects
are observed upon addition of Brownian particles on the relaxation spectra of the micellar fluid.
Further, the self-assembled surfactant aggregates are observed to strongly influence the shorttime particle dynamics. The results are interpreted with a microstructural model for particle selfassembled surfactant mixture.
12-14
Interfacial Rheology of Globular and Flexible Proteins at the Hexadecane/Water Interface:
Comparison of Shear and Dilatation Deformation
E. M. Freer, K.S. Yim, G.G. Fuller, C.J. RADKE, Chemical Engineering Departments,
University of California, Berkeley, CA, Stanford University, Stanford, CA,
radke@cchem.berkeley.edu
After long-time exposure, protein adsorption at fluid/fluid interfaces produces interfacial gel-like
networks. We utilize interfacial shear and dilatational rheology to probe the structure of a
globular protein, lysozyme, and a disordered protein, -casein, at the hexadecane/water
interface. For lysozyme, the shear moduli grow with interface age indicating a transition from
fluid-like behavior at early times to solid-like network formation at later times. Conversely, the
interfacial shear moduli of -casein change very little with interface age. The strong protein
intramolecular interactions that stabilize the native conformation of lysozyme act as kinetic
barriers to conformational change and later become strong intermolecular interactions that result
in aggregation at the interface. The interfacial dilatational storage modulus is comprised of a
static response and a dynamic response. The dynamic contribution corresponds to rearrangement
and reconfiguration of the protein molecules within the interface and gives a measure of the
strength of interprotein linkages. Globular lysozyme, once adsorbed, resists compression giving a
high dilatational storage modulus. Contrastingly, -casein exhibits only a small interfacial
dilatational storage modulus. For the first time, we establish that surface shear and dilatational
moduli measure quite different but complementary molecular characteristics of adsorbed proteins
at fluid/fluid interfaces.
12-15
Influence of Non-Newtonian Behavior on the Dynamic Interface Shapes of Polymer Melts,
Solutions and Boger Fluids
GITA SEEVARATNAM*, Stephen Garoff**, Lynn M. Walker*, Center for Complex Fluids
Engineering, Department of *Chemical Engineering and **Physics, Carnegie Mellon University,
Pittsburgh, PA, gseevara@andrew.cmu.edu
In this work, we characterize the liquid-vapor interface shape during forced wetting to quantify
the effect of fluid elasticity on interface shape. The fluid mechanics near the three phase (solidliquid-vapor) are complex and the impact of elasticity on this inherently confined geometry is
poorly understood. We find that two polymer melts, polyisobutylene (PIB) and polystyrene (PS)
exhibit dynamic wetting characteristics of a weakly elastic fluid. We study dynamic wetting by
observing the liquid-vapor interface formed on the outside of a silica surface forced into a bath of
the test fluid at controlled rates. The results show that the interface shapes of these fluids deviate
from the prediction of models that include only Newtonian flow behavior. Using standard
rotational rheometry, we examine the shear rates needed to cause non-Newtonian behavior in
these fluids and ask where such shear rates arise near the contact line. Experiments on xanthan
gum solutions have shown that an increase in shear thinning in the high shear region near the
contact line decreases the curvature of the interface near a moving contact line. However, fluids
with some level of elasticity and minimal shear thinning show an increase in curvature near the
contact line. Differences in these fluid behaviors and ramifications on interface shape will be
discussed.
12-16
The Effect of Nonadsorbing Macromolecules on the Particle Dynamics Near an Interface
R. J. OETAMA, J.Y. Walz, Department of Chemical Engineering, Yale University, New Haven,
CT, ratna.oetama@yale.edu
The optical technique of total internal reflection microscopy (TIRM) was used to study the
normal Brownian motion of a single colloidal particle near an interface. Using our data analysis
method, the particle’s spatially-varying diffusion coefficient can be determined without any
knowledge of the forces acting on the particle. Experiments were performed in solution
containing small silica nanospheres, polyacrylic acid, and clay platelets to investigate the effect
of nonadsorbing species on the dynamics of near-contact particle motion. This talk will focus on
the dynamic particle behavior near a solid wall in dilute colloidal suspensions of synthetic clay
particles (laponite) that are slowly thickening. Measurements of the equilibrium potential energy
profile were also obtained which indicate the development of structures in the laponite solution
over time.
12-17
Dramatic Increase in Viscosity with Temperature as a Result of a Thermoreversible
Vesicle-to-Micelle Transition
Tanner S. Davies, SRINIVASA R. RAGHAVAN, Department of Chemical Engineering,
University of Maryland, College Park, MD, sraghava@eng.umd.edu
Complex fluids based on surfactants usually show a decrease in their viscosity upon heating. We
report an example of the opposite effect, where the viscosity sharply rises upon heating as a
result of a microstructural transformation. This phenomenon is observed in mixtures of the
cationic surfactant, cetyl trimethylammonium bromide (CTAB) and a methyl-substituted
salicylic acid. Such mixtures self-assemble in aqueous solution to form unilamellar vesicles at
room temperature. Upon heating, the vesicles are transformed into long, cylindrical micelles and
consequently, the sample changes from a low-viscosity, Newtonian fluid to a viscoelastic, shearthinning fluid. The zero-shear viscosity increases by a factor of 1000 or more with increasing
temperature. The ensuing microstructural changes as a function of temperature are confirmed by
small-angle neutron scattering (SANS) measurements. We will discuss and correlate the
rheology and SANS data for various sample compositions.
12-18
Structure and Mechanical Properties of Nanocomposites: Proteins and Nanoparticles
Templated in Self-Assembled PEO-PPO-PEO Mesophases
DANILO C. POZZO, Lynn M. Walker, Center for Complex Fluids Engineering, Department of
Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, lwalker@andrew.cmu.edu,
dpozzo@andrew.cmu.edu
Highly ordered self-assembled block copolymer mesophases present an attractive way of
transferring their structure to otherwise disorganized nanometer sols (proteins or inorganic
nanoparticles). Unlike other “bottom-up” nanoparticle organization methods, the tunable
structure of the ordered block-copolymer phase provides increased control over the structure of
the templated nanoparticle arrays. This method allows us to organize large numbers of particles
(1020/L) into controllable three-dimensional structures. Additionally, the use of thermoreversible
polymer mesophases permits the stable dispersion of pre-made nanoparticles or globular
proteins. In this study, we use rheology to thoroughly evaluate the mechanical properties of these
nanocomposites and find that mechanical properties are strongly altered when the concentration
of dispersed nanoparticles approaches and exceeds the number of available template sites. Smallangle neutron scattering (SANS) is used to evaluate the coupling between matrix and
nanoparticle order. By using solvents containing isotope mixtures in SANS we are able to
separately study the structure of the organic and inorganic phases through the variation of the
neutron scattering contrast. It is found that the nanoparticles are templated by the polymer gel
and that the level of organization is dependent on a number of controllable variables. We
quantify the influence of relative concentration, relative dimensions and temperature on both the
nanoscale structure and macroscopic composite properties.
12-19
Physical Gelation and Rheological Properties of Cationic Telechelic Polyelectrolytes
G. Gotzamanis1, F. Bossard2, R. Lupytsky3, T. Aubry2, S. Minko3 and C. TSITSILIANIS1,
1
Department of Chemical Engineering, University of Patras 26504, Patras, Greece and Institute
of Chemical Engineering and High Temperature Chemical Processes, ICE-FORTH, 2Laboratoire
de Rhéologie, Université de Bretagne Occidentale, 6 avenue Victor Le Gorgeu, 29285 Brest
Cedex, France, 3Department of Chemistry, Clarkson University, Potsdam, NY
Telechelic polyelectrolytes (TP) are a novel class of Associative Polymers (AP) constituted from
a long polyelectrolyte chain end-capped by hydrophobic short polymeric chains. The main
feature that makes TP, distinguished from the conventional telechelic APs (non ionic
hydrophylic part) is that the chain conformation of the soluble part can be controlled by external
conditions such as pH and ionic strength. At a certain pH (depending of the polyelectrolyte
nature) and at free salt conditions the central chain adopts a stretched conformation, which has
fundamental consequences on the TP association and rheological properties. In this work
cationic TP constituted of a long PDMAEMA end-capped by short PMMA blocks have been
synthesized end explored in aqueous media. The motivation of this work was to combine the
excellent properties of telechelic polyelectrolyte physical gels with the benefits of
biocompatibility and capability of cationic macromolecules to be complexed with DNA. Above
cgel (0.1 wt%) a transient physical network is formed through an open association mechanism,
macroscopically observed by a rapid increase of the solution viscosity. This pronounced
concentration dependence is marked, up to a polymer concentration of about 1%wt. Above this
critical polymer concentration, a stiff hydrogel is formed for which rheological properties are not
significantly strengthened by polymer concentration enhancement. In this higher polymer
concentration regime, the physical hydrogel exhibits a peculiar rheological behavior
characterized by a Newtonian plateau at low shear stresses followed by a viscosity drop of about
five decades, attributed to apparent yield stress behavior, a second Newtonian plateau at
intermediate shear stresses and a shear thinning at high stresses.
12-20
Numerical Simulation of Methane Hydrate in Sandstone Cores
KAMBIZ NAZRIDOUST, Goodarz Ahmadi, Department of Mechanical and Aeronautical
Engineering, Clarkson University, Potsdam, NY, ahmadi@clarkson.edu
Production of methane gas from hydrate dissociation in a core is studied. It is assumed that the
core is porous with the pores being partially saturated with hydrate. Using the Fluent™ code
with appropriate user defined functions, an axisymmetric model of the core is developed and
solved for multiphase fluid flow during the hydrate dissociation. The model contains three
separate phases of hydrate (solid/heavily viscous fluid), methane (gas), and water (liquid). The
hydrate zone is stationary but water and gas can move freely. For different core temperatures and
various production valve pressures, time evolutions of gas and water during hydrate dissociation
are evaluated and variations of temperature and pressure are simulated. Variations of relative
permeability of the core are included using Corey’s model for porous media. Porosity of the
core also changes with saturation of hydrate. It is shown that to maintain a constant natural gas
production rate, the production valve pressure must be decreased with time. The simulation
results show that the process of natural gas production is a sensitive function of reservoir
temperature and hydrate zone permeability.
12-21
A Study of Three-Phase Liquid-Gas-Solid Flows in Microgravity
XINYU ZHANG, Goodarz Ahmadi, Department of Mechanical and Aeronautical Engineering,
Clarkson University, Potsdam, NY
An Eulerian-Lagrangian computational model for simulations of gas-liquid-solid flows in
microgravity was developed. In this study, the liquid phase was modeled by a volume-averaged
system of Eulerian governing equations, whereas motions of particles and bubbles were
evaluated using Lagrangian trajectory analysis approach. It was assumed that the bubbles
remained spherical and their shape variations were neglected. The two-way interactions between
particle-liquid and bubble-liquid were accounted for in the study. The discrete phase equations
used included drag, lift, buoyancy, and virtual mass forces. Interactions between particle-particle
and bubble-bubble were accounted for by the hard sphere model. The bubble coalescence was
also included in the model. The predicted results under normal gravity condition were compared
with the available experimental data in earlier simulations, and good agreement was obtained.
The transient flow characteristics of the three-phase flow were studied and the effects of gravity,
inlet bubble size, bubble number density and bubble superficial velocity on variation of flow
characteristics were discussed. The simulations for low gravity showed that most bubbles are
aggregated in the inlet region, and due to the longer residence time and bubble coalescence, and
the Sauter mean bubble diameter becomes rather large which can be more than10 mm.
12-22
A New Friction Factor Correlation for Laminar and Single-Phase Fluid Flow through
Fractured Rocks
KAMBIZ NAZRIDOUST1, Goodarz Ahmadi1 and Duane H. Smith2, 1Engineering, Clarkson
University, Potsdam, NY, 2National Energy Technology Laboratory, U.S. Department of Energy,
Morgantown, WV, ahmadi@clarkson.edu
Single- and multi-phase flow through fractured media occurs in various situations, such as
transport of dissolved contaminants through geological strata, sequestration of carbon dioxide in
brine-saturated reservoirs, and in enhanced oil recovery from depleted field. In the present study
fluid flows through individual fractures were simulated. A post-processing code was developed
and used to generate the three-dimensional fracture inside AutoCAD package from the CT scan
data. Several sections along the fracture were considered and GambitTM code was used to
generate unstructured grid for flow simulation. Single-phase flows through the fracture section
with different flow rate were studied. It was shown that the pressure drop was dominated by the
lowest height passages of the fracture. For geological reservoir simulations, the parallel plate
model has often been used for estimating flows through fractures. It was shown that the parallel
plate flow model with inclusion of the tortuosity effects was in reasonable agreement with the
presented CFD simulation results. Based on the simulation data, a new expression for the friction
factor for flows through fractures was developed and the model predictions were compared with
the simulation results and favorable agreement was achieved.
13-1
The Role of Phase Science in Colloid Science
ROBERT G. LAUGHLIN, Clarkson University, Potsdam, NY, Rua Barão de Ipanema 130/202,
Copacabana, Rio de Janeiro/RJ Cep 22050-030, Brasil, rglaughlin@hotmail.com
Those systems of historic interest in the development of colloid science do not display
discontinuous changes of state over the range of temperatures studied, and the solvent is not
incorporated into the dispersed phase. The dispersed phases of water-insoluble surfactants,
however, do incorporate solvent water – lots of it. They also undergo discontinuous phase
changes near ambient temperatures. The incorporation of solvent has a profound effect on the
ratio of coexisting phases, and all those properties associated with phase ratios. Incorporation as
crystal hydrates may introduce complex and interesting colloid chemistry when these are heated
past peritectic temperatures.
In biological cell membranes, temperature changes which pass the chain melting temperature
should affect not only the membrane structure, but also its water composition. Such changes are
predicted to affect the water content of the cytoplasm, and thereby the thermodynamic activity
of every water-soluble component in the cytoplasm. The impact of these changes has been
neglected, but may extend far beyond the structural perturbations that have been the focus of
interest to date.
13-2
What’s New with The Gibbs Adsorption Equation?
B. WIDOM, Department of Chemistry, Baker Laboratory, Cornell University, Ithaca, NY,
bw24@cornell.edu
The Gibbs adsorption equation and some of its implications will be recalled. What had for a
quarter century been thought to be the analog of the Gibbs adsorption equation for the line of
three-phase contact was recently discovered to be incorrect. A brief account of that problem, and
of the related question of how adsorptions at the line of three-phase contact behave as a transition
to complete wetting is approached, will be presented.
13-3
Some Applications of Surfactant Phase Diagrams
STIG E FRIBERG, Chemistry Department, University of Virginia, Charlottesville, VA,
sfbg@bellsouth.net
A series of examples are presented for which the phase diagrams of the systems were either
necessary or helpful to solve problems within emulsions , microemulsions and foams.
The examples vary from the stability of foams from non-polar solvents to formulation of
microemulsons to the action of hydrotropes to the structural changes in simple emulsions during
evaporation. Finally the advantage of applying analytical geometry to such systems is
exemplified.
13-4
“Stained Glasses”, Thin Liquid Films and Lamellar Liquid Crystals
JAN CZARNECKI1, Jacob Masliyah2, Nikolay Panchev2,3, Shawn Taylor2,4, 1Syncrude Canada
Ltd., Edmonton Research Centre, 2Department of Chemical Material Eng., University of Alberta,
3
Visiting student from Institute of Physical Chemistry, Bulgarian Academy of Science, 4Current
affiliation:
Schlumberger
Reservoir
Fluids
Center,
Edmonton,
AB,
Canada,
czarnecki.jan@syncrude.com
Foam films drawn from aqueous solutions of sodium naphthenates and Aerosol OT, at
concentrations close to or just above the lamellar liquid crystal (LLC) phase boundary, contain
domains of uniform color (thus of uniform thickness) with sharp boundaries, resembling 'stained
glasses'. To be colored, the domains must be thicker than half of the visible light wavelength.
Analysis of Newton rings shows that these domains exist well above 1 m thickness. To have a
uniform thickness, the domains must contain hundreds of ordered layers of molecular dimension.
Statistical mechanical considerations for hard spheres (which represent micelles) predict the
existence of only a few such layers. It is thus likely that Wasan and Nikolov’s model of film
stratification, based on parallel layers of ordered micelles, describes film structure at moderate
surfactant concentrations. At high concentrations however, LLC-like organization is likely
responsible for film stratification, in agreement with pioneering works of Stig Friberg.
13-5
Emulsion Structure and Stability: Role of Depletion and Structural Forces
DARSH WASAN, Alex Nikolov, Illinois Institute of Technology, 10 West 33rd Street, Chicago,
IL, wasan@iit.edu
In this paper, we will review the recent work performed in our laboratory in the areas of structure
and stability of emulsions and foams. We will particularly highlight the role of long-range
oscillatory forces, including attractive depletion and structural, in controlling dispersion stability.
We have developed a novel hybrid surface force apparatus referred to as the capillary force
balance in conjunction with a differential interference microscopy method to investigate
surfactant micelle or nanoparticle structuring phenomenon inside thinning liquid films confined
between droplets or foam bubbles in concentrated colloidal dispersions. In addition, we have
used a nondestructive Kossel diffraction technique to obtain the structure factors, and the
advanced optical imaging method to obtain the emulsion radial distribution function to determine
the effective inter-droplet interactions. We have used these techniques to investigate the effects
of surfactant type (i.e., water soluble and oil soluble), proteins, gums, fat substitute, temperature
and shear rate on emulsion structure and stability. We have carried out theoretical calculations
using the Ornstein-Zernike equation of statistical mechanics and Monte Carlo simulations to
elucidate the role of long-range oscillatory forces in concentrated dispersions, and showed that
the experimental results are consistent with theoretical simulations.
13-6
Phase Diagrams of Ternary Lipid Bilayer Mixtures Containing Cholesterol
GERALD W. FEIGENSON, Field of Biophysics, Cornell University, 201 Biotechnology
Building, Ithaca, NY, gwf3@cornell.edu
Determination of the phase diagram for a 3-component bilayer mixture of lipids requires use of
several different methods in order to resolve ambiguities in the phase boundaries. We employed
fluorescence spectroscopy and microscopy, ESR spectroscopy, x-ray and neutron diffraction, and
light scattering. Mixtures containing cholesterol that model the outer leaflet of animal cell
membranes show rich phase behavior. DSPC/DOPC/cholesterol (distearoyl-PC/dioleoylPC/cholesterol
phases. In contrast, DPPC/DLPC/chol (dipalmitoyl-PC/dilauroyl-PC/cholesterol) shows a much
Sp
13-7
Phase Behavior and Structure in Mixtures of Surfactants and Hydrotropes
ERIC W. KALER, Yamaira Gonzalez, Department of Chemical Engineering, Colburn
Laboratory, University of Delaware, Newark, DE, kaler@udel.edu
Hydrotropes are amphiphilic molecules with hydrophobic portions too small to form micelles.
Hydrotropes bind strongly to the surface of micelles and can facilitate the formation of
interesting microstructures such as elongated micelles and vesicles. We have investigated the
formation and polymerization of worm-like micelles and vesicles made of polymerizable
surfactants. The use of water-soluble di-azo free radical initiators for these studies led to the
discovery of the spontaneous formation of vesicles from simply mixing the initiator with
surfactant alone, without polymerization. The characterization of these mixtures indicated that
initiators behave as hydrotropes. Basic amino acids have similar molecular functionality and
show a similar hydrotropic behavior, including the formation of gels. This work reveals the
power of hydrotropic molecules in driving structural changes in surfactant solutions.
13-8
A New Approach to Dilute and Concentrated Lamellar Phases in Phase Diagrams of
Nonionic Surfactants
COSIMA STUBENRAUCH, Department of Chemical and Biochemical Engineering, University
College Dublin, Belfield, Dublin 4, Ireland, cosima.stubenrauch@ucd.ie
The present contribution is about new results on two peculiar features in connection with the
lamellar phases (L ) in binary aqueous solutions of nonionic surfactants. The first striking
feature is the formation of highly dilute L phases down to 1 wt.-% of surfactant, which has been
observed for a small number of nonionic surfactants which are all of the alkyl polyglycol ether
(CiEj) type. So far, in binary H2O - CiEj systems either the absence or the presence of a dilute L
phase has been reported. In the latter case, the dilute and the concentrated L phase are always
connected continuously. However, for one particular silane surfactant, namely
(CH3)3Si(CH2)6(OCH2CH2)5OCH3, two disconnected L phases were observed. Systematic
investigations of the phase behaviour of the binary system H2O - C10E4 as well as of the
pseudobinary systems H2O - C10E4/C10E5 enabled us to answer adequately the following
questions: (a) Is the disconnected L phase a peculiarity of the silane surfactant or a general
feature of nonionic surfactants? (b) Are there any structural differences between the connected
and the disconnected L phases? (c) What is the process which leads to the disconnection of the
L phase?
13-9
Spontaneous Emulsification and its Relationship to Phase Behavior: Review and Recent
Developments
CLARENCE A. MILLER, Department of Chemical Engineering, Rice University, Houston, TX,
camill@rice.edu
The relationship of spontaneous emulsification to phase behavior is reviewed with emphasis on
results obtained in recent years. Several studies have provided insight on the mechanism of selfemulsification of oils to form oil-in-water emulsions consisting of small droplets. In particular,
diffusion and/or chemical reaction can cause changes in composition and hence in spontaneous
curvature of surfactant films, which promote inversion from an oil-continuous to a watercontinuous microemulsion. Since the latter is not able to solubilize all of the oil present, local
supersaturation and subsequent nucleation of oil droplets occurs. Under suitable conditions the
lamellar liquid crystalline phase is formed during the inversion process and coats the small
droplets, thereby hindering coalescence and reducing the surfactant concentration required to
form small droplets. Self-emulsification can also occur without large changes in spontaneous
curvature when the surfactant films are initially near the balanced state of zero spontaneous
curvature. Formation of the lamellar phase during this process appears to be essential for
obtaining small droplets. “Nanoemulsions” with drop sizes of order 100 nm or less have been
produced by self-emulsification processes which involve spontaneous emulsification
accompanied by gentle stirring. When polymer is dissolved in the droplets, removal of the
solvent yields small polymer nanoparticles, which are of interest in applications such as drug
delivery. The results of these studies demonstrate that knowledge of equilibrium phase behavior
is important in choosing suitable systems and conditions for self-emulsification.
13-10
Water-in-Crude Oil Emulsions – Stability Mechanisms and Environmental Aspects
JOHAN SJÖBLOM, Pål V. Hemmingsen, Gisle Øye, Andreas Hannisdal, Marit-Helen Ese,
Øystein Brandal, Maria Häger, Ugelstad Laboratory, Department of Chemical Engineering,
NTNU, N-7491 Trondheim, Norway, johsj@chemeng.ntnu.no.
The keynote lecture is going to view the chemistry of heavy crude oil components and their
interaction forms. After this the formation, stabilization and destabilization of water-in-crude oil
emulsions is viewed. The stabilizing role of the heavy components in the crude oil is discussed
together with ageing effects.
Particle-stabilization is viewed from three different aspects. The impact of the association of
asphaltenes to form organic nanoparticles is well-known from previous studies. In addition the
role of inorganic fines and small metalnaphthenate particles is discussed. Inorganic fines, mostly
oxides from the formation, will have a natural tendency to accumulate at w/o interfaces
depending on their contact angle. However, what is highly changing the behaviour of these fines
is the adsorption of components from the crude oil onto their surface. These components are
mainly resins and asphaltenes. Another route to form fines is the reaction between organic
naphthenic acids and divalent cations. It is shown by means of dynamic interfacial tensions that
reactions over w/o interfaces are important in this respect.
It becomes more and more important to understand the underlying stabililization mechanisms of
the dispersed material due to the tougher regulations on discharges by the state authorities.
Normally the discharges include emulsions (o/w), dispersed particles (with and without coating)
and dissolved components. However, since the dissolved components will include both
naphthenic acids and polar components the possibility of finding dispersed lyotropic liquid
crystals should be profound. In this study we report for the first time on the results from phase
diagram studies based on model components representing naphthenic acids and polar phenols in
water.
13-11
The Role of Colloid Science and Electrokinetics in Oil Sands Processing
JACOB MASLIYAH, Zhenghe Xu, Department of Chemical Engineering, University of Alberta,
Edmonton, AB, Canada, Jacob.masliyah@ualberta.ca
Canadian bitumen recovery from oil sands will continue to increase in the next decades. The
present oil sands development in Alberta is on a massive scale. The three existing open-pit oil
sand plants in Alberta produce about 700,000 barrels of bitumen a day. Increased bitumen
production requires development of new technologies and improvement of existing ones. As
well, it requires increasing skilled engineers to handle the increased production levels.
The presentation deals with research efforts at the University of Alberta that seek a better
understanding of bitumen recovery from oil sands. A summary will be presented on the use of
the state of the art techniques to probe the interfacial properties of hydrocarbon-water interfaces
to elucidate the mechanisms of air-bitumen attachment, bitumen-solids separation and
stabilization of water-in-oil emulsions. Among the techniques to be discussed are: Atomic Force
Microscope, zeta potential distribution measurements and Langmuir-Blodgett trough.
13-12
Relations Between the Molecular and Nanocolloidal Structure of Asphaltenes
OLIVER C. MULLINS, Schlumberger-Doll Research (SDR), Ridgefield,
omullins@ridgefield.oilfield.slb.com
CT,
The science of asphaltenes, the most aromatic fraction of crude oil, has advanced significantly in
recent years. Asphaltene molecular weight has recently been elucidated after decades of
controversy; time resolved fluorescence depolarization results yielded critical results. Asphaltene
molecular architecture has also largely been resolved; x-ray Raman spectroscopy delineated
fused aromatic ring geometry. These findings will be reviewed. The Critical Nanoaggregate
Concentration (CNAC) of asphaltenes has also recently been delineated for example by high-Q
ultrasonic spectroscopy; a decade of literature was misinterpreted (Professor Friberg played a
central role in correcting the problem). The governing physics of nanoaggregate formation is
evident in asphaltene molecular structure; function follows structure. These precepts which are
largely 'freshman chemistry' are shown essentially to define the identity of asphaltenes.
13-13
Liquid Crystallinity and Emulsion Formation in Ternary Oil-Water-Acid/Soap Systems
Comprised of Model Naphthenic Acids and Their Mixtures with Asphaltenes from
Petroleum Fluids
Marit-Helen Ese, M. Lupe Marques, PETER K. KILPATRICK, Department of Chemical and
Biomolecular Engineering, North Carolina State University, Raleigh, NC, peter-k@ncsu.edu
In an effort to better understand the role of naphthenic acids and soaps in stabilizing water-in-oil
emulsions, we conducted a study of emulsion type and stability in model ternary systems
comprised of oil, water, and aromatic and alicyclic ringed acids as functions of pH and acid/soap
concentration. The acids selected for study were b-cholanic acid, deoxycholic acid, heptyl
benzoic acid and pentane cyclohexanoic acid. The pH of the aqueous phase was systematically
varied from 5-13 and the concentration of acid/soap was varied from 0.5-10% (w/w). All of
these model systems clearly indicated a transition from oil-in-water emulsions at low pH, to
water-in-oil emulsions at higher pH (which varied with the architecture of the hydrophobic group
on the acid). At sufficiently high pH, some of the systems reverted back to o/w emulsions.
These results are consistent with the interfacial film of acid/soap molecules adopting a lamellar
structure when the balance among effective head group size due to electrostatic repulsion and the
steric repulsion of cyclic hydrophobic moieties confers a molecular packing parameter close to
unity on the system. Under these conditions of balance, there is clear evidence from optical
polarizing microscopy that the interfacial films are liquid crystalline. This appears to be a
universal phenomenon with monomerically pure acid/soaps. We have also explored the
interaction of asphaltenes and model naphthenic acid/soaps as a function of aqueous phase pH
and concentration of acid/soap. Under appropriate conditions of pH and using model naphthenic
acids with appropriate hydrophobic groups, the presence of the acid/soap can dramatically
destabilize w/o emulsion, even at extremely low concentrations (0.05% (w/w)). Interestingly,
when the hydrophobic moiety of the acid is sufficiently aromatic or fused ringed aromatic, the
addition of the acid/soap can dramatically stabilize w/o asphaltene emulsions. The results
suggest judicious ways of minimizing w/o emulsion challenges during the production and
refining of petroleum fluids.
13-14
Studies on Properties of Interfacial Active Fractions from Crude and Its Effect on Stability
of Crude Emulsions
MINGYUAN LI, Jixiang Guo, Meiqin Lin, Zhaoliang Wu, EOR Research Center, University of
Petroleum Beijing, Beijing, P.R. China, myli@public3.bta.net.cn
The influence of indigenous interfacial active fractions from crude on the interfacial property
between water and crude and its effect on stability of crude emulsions was studied.
It was found that the fatty acid and carboxyl acids in the fractions of asphaltene from Gudong 1#,
Gudong 4# crude and of resin from Daqing crude are responsible for decreasing the interfacial
tension between the crude oils and water. These acids have smaller relatively molecule mass,
more branch chain more oxygen but they were not able to stabilize emulsion formed by model
oil and water. It was the acids with lager relatively molecule mass are responsible for stabilizing
the emulsions. For model oil and alkali solution system the soap formed by fast reaction of the
acid, ester with smaller relatively molecule mass and alkali is responsible for decreasing the
interfacial tension between crude oil and water. The soap formed by slow reaction of the acid,
ester with lager relatively molecule mass and alkali is responsible for stabilizing crude oil
emulsions.
13-15
Phase Equilibria and Separation of Amphiphilic Extractives from Wood
PER STENIUS1, Esa Pirttinen1, Kari Kovasin2, 1Laboratory of Forest Products Chemistry,
Helsinki University of Technology, Espoo, Findland, 2SciTech-Service Ltd, Rauma, Findland,
Per.Stenius@hut.fi
Phase equilibria, particle size and kinetics of phase separation in aqueous sodium
alkanoate/sodium rosinate acid systems containing solubilizates representative of water-insoluble
compounds in wood (sterols, long-chain alkanols) was investigated by light transmission and
backscattering measurements using TurbiScan analyzers. Solution conditions corresponded to
those obtaining during cooking and washing of softwood pulp (“black liquor”) and separation of
crude tall oil. Creaming rates of the lyotropic phases were highly dependent on the ratio
alkanoate/rosinate and the amount of solubilizate. Two-phase regions were found in which
lamellar phase was in equilibrium with very dilute solutions, and separation was very efficient.
This was utilized to develop method of improving the separation of soaps from dilute systems by
addition of non-polar solubilizates. The method was applied successfully, in laboratory scale and
mill trials, to the separation of soaps by adding non-polar solubilizates isolated from wood. The
amounts of residual dissolved alkanoates and resinates could be reduced by 70-80 %, depending
on the amount of “auxiliary” solubilizate added.
13-16
Building an Institute to Serve Industry with Innovations from Surface Chemistry Research
BRUCE LYNE, Institute for Surface Chemistry (YKI), Box 5607, SE-114 86, Stockholm,
SWEDEN, bruce.lyne@surfchem.kth.se
The Institute for Surface Chemistry (Ytkemiska Institutet, or YKI for short) was created to
promote research in interfacial science that had relevance to industry. YKI started as a
laboratory under the auspices of the Royal Swedish Academy of Engineering Science on the
campus of the Royal Institute of Technology (KTH) in Stockholm. It drew strength from strong
departments of physical chemistry at KTH, Lund, Uppsala, and Chalmers. Stig Friberg led YKI
from its inception as a free-standing institute in 1969 until he left for the University of Missouri
at Rolla in 1976. During his time as president he drove the reduction of surface chemistry theory
to practice. By providing value to industry he was able to build a membership of 45 companies
in the Association for Surface Chemistry Research, later to become the majority owners of YKI.
Stig’s ability to interpret phase diagrams as an aid in formulation was a significant contribution
to YKI’s growing rapport with its industrial client base.
Today, YKI remains strongly linked to academe in Sweden with doctoral students inscribed in
all of the above-mentioned universities, but it can count active working relations with 100
universities and institutes around the world. More than half of the articles produced by the YKI
staff are coauthored by scientists from these universities and institutes. This open innovation
model has helped to attract 70 international member companies covering ten industrial sectors to
the Association for Surface Chemistry Research. The flow of ideas from this network of
research partners and further development at YKI provides technology platforms on which are
built consortium projects for industry. For example, cooperative work with Swedish and
American universities on the creation of nanostructured materials from self assembly has been a
fountainhead for delivery and release projects in a broad range of applications such as biocides in
paint, drug delivery, fragrance release, sensor encapsulation, and even a new class of pigments
from dyes dissolved in inorganic matrices. Similarly, innovation in surfactant chemistry has led
to many industrial projects such as triggered foam or emulsion breaking, particle stabilized
emulsions, surfactants that totally biodegrade, and surfactants with antibacterial and antifungal
attributes. The institute that Stig Friberg started is now a company that is positioned to do well
in the increasingly knowledge-based economy in which it operates.
13-17
Crystal Comets: Dewetting during Emulsion Droplet Crystallization
PATRICK T. SPICER1, Richard W. Hartel2, 1Complex Fluids Research, Procter & Gamble Co.,
8256 Union Centre Blvd., West Chester, OH, USA, 2Department of Food Science, University of
Wisconsin-Madison, Madison, WI, spicer.pt@pg.com
Liquid oil emulsion droplets can violently dewet their own solid crystals during crystallization as
a result of surfactant adsorption. The crystal shape formed is a function of the relative rates of
dewetting and crystallization as controlled by surfactant adsorption, cooling rate, and lipid
purity. For negligible dewetting rates, crystals nucleate and grow within the droplet. At similar
crystallization and dewetting rates, the droplet is propelled around the continuous phase on a
crystalline “comet tail” much larger than the original droplet. Rapid dewetting causes the
ejection of small discrete crystals across the droplet’s oil-water interface. It is shown that the
crystallization behavior can be controlled by tuning the molecular packing geometry of the
surfactant.
13-18
Dispersions of Glyceryl Monooleate with PEO-Copolymers Bearing Lipid-Mimetic
Hydrophobic Blocks in Water.
S. Rangelov, M. ALMGREN, Department of Physical Chemistry, Uppsala University, Box 579,
SE-751 23, Uppsala, Sweden, almgren@fki.uu.se
Stable dispersions of the cubic phase of glyceryl monooleate (GMO) in water were first obtained
by K. Larsson and suggested to require the presence of a three phase area, involving the lamellar
phase in addition to the cubic and water. Using suitable stabilizing agents such as poloxamers, it
was later shown that stable cubic particles can be obtained also within the two phase area.
Furthermore, GMO and sodium cholate form a L3 phase in brine; dilution of this phase in excess
brine results in coexisting L3 and cubic particles with some stability.
We have prepared copolymers with PEO as hydrophilic block and blocks containing two to eight
dodecyl chains as hydrophobic anchors, in both di- and triblock versions. Dispersing a polymer-
GMO mixture in glycerol, and adding this dispersion to excess water, results in the formation of
small particles with a broad variation of morphologies depending on the amount and type of
copolymer. The particles have been studied by cryoTEM imaging, and their morhophologies will
be rationalised from packing and phase behavior.
13-19
Worm-like Micelles and Microemulsions
HIRONOBU KUNIEDA, Graduate School of Environment and Information Sciences,
Yokohama National University, Tokiwadai 79-7, Hodogaya, Yokohama, Japan,
kunieda@ynu.ac.jp
Wormlike micelles form visco-elastic solutions in which long-flexible micelles are entangled.
CTAB is a well-known cationic surfactant, which produces such a visco-elastic system in the
presence of some inorganic and/or organic salts. Wormlike micelles are also produced by
combining hydrophilic surfactant with cosurfactant in ionic and nonionic surfactant systems.
Upon addition of oil to the viscoelastic systems, the considerable reduction in viscosity takes
places in some oil systems whereas it is also possible to maintain the viscosity in other oil
systems. These systems are also able to call microemulsions. Phase behavior of wormlike
micelles and their microemulsions in the mixed surfactant systems will be reported as well as
their visco-elastic behavior and structures.
13-20
Friberg Correlations in Oil Recovery
GEZA HORVATH-SZABO, Lamia Goual, Alejandro Magual, Jacob H. Masliyah, Department
of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada,
ghszabo@usa.net
In the presence of liquid crystal phase (LC-phase), the stability of emulsions increases
dramatically. Consequently, the phase behavior of oil/organic-solvent/water systems has an
effect on the efficiency of separation of emulsified water. Since LC-phase was identified in
bitumen/toluene/water system under alkaline conditions, the phase behavior of sodiumnaphthenates/organic-solvents/water was investigated in detail revealing the presence of lamellar
LC, microemulsion and high viscosity gel phases. In this system the emulsion stability has a
strong correlation with the phase behavior. The LC-phase is located between the dispersed
aqueous droplets and organic medium.
In crude oil systems having low surfactant concentration, the volume of the interfacial LC-phase
becomes so small that it cannot be identified easily by polarization microscopy. For this case
quartz crystal microbalance (QCM) and electroacoustic spectroscopy (EAS) were introduced for
the characterization of the adsorbed surface-active materials at the oil-water interface in bitumentoluene systems. EAS revealed a time dependent relaxation of the surface charge of water-in-oil
emulsions. Depending on the bitumen concentration, two distinct adsorption regimes were
discovered by QCM. The threshold concentration between these adsorption regimes is in
agreement with the critical bitumen concentration corresponding to the rigid-to-flexible
transition of the o/w interface.
13-21
Phase Behaviour in Confinement Studied with a Surface Force Apparatus
HUGO K. CHRISTENSON, School of Physics and Astronomy, The University of Leeds, Leeds,
United Kingdom, h.k.christenson@leeds.ac.uk
The free energy of a surface has a major influence on phase behaviour in systems where the areato-volume ratio is large. These include finely dispersed solids and liquids as well as substances
confined to meso- and microporous solids. In a surface force apparatus mica surfaces at or close
to contact form a single model pore in which surface energy effects on phase behaviour may be
conveniently studied. Capillary condensation of liquid from undersaturated vapour is the most
familiar example of a surface-induced shift of bulk phase behaviour. I will describe
experimental studies of capillary condensation and related phenomena such as melting-point
depression in a pore, direct condensation of solid from vapour and capillary evaporation.
13-22
A Magneto-Optical Apparatus for Boundary Localization of Ternary Phase Diagrams
SYLVAIN DESERT, CEA Saclay, LLB, Bat 563, 91191 Gif/Yvette, France, desert@dsmmail.saclay.cea.fr
Knowledge of the phase diagram of any complex fluid, either colloidal dispersions, surfactant
solutions, polymers or lipids, is the first step needed for efficient formulation in industry or to
investigate molecular interaction.
An optical apparatus designed for the mapping of binary or ternary phase diagrams will be
described. A polychromatic polarized light illuminates a sample and the rotation of its
polarization is measured with a spectrometer for various magnetic fields. The measured
parameters are the natural and magnetic rotatory power of the sample which allows the
concentration retrieval of every compound to be done. Results show that the apparatus is suitable
for correct positioning of single phase boundary on the ternary water - n-dodecyl-β-d maltoside sodium chloride system.
13-24
Surface Chemical Aspects of Treatments with Dental Implants
PER-OLOF J. GLANTZ, Department of Prosthetic Dentistry, Faculty of Odontology, S- 214 21 Malrmo,
Sweden, Per-Olof.Glantz@od.mah.se
Reviews of factors influencing the outcome of restorative treatments with dental implants have demonstrated
that lack of proper control of implant surface chemistry is one of the most like reasons for the frequent
reported failures of such treatments prior to the introduction of so-called osseointegrated Ti-implants in the
1980-ies. Thus, with earlier implant systems surface contamination was often present as the results
of poor mechanical finishing and/or sterilization procedures. Such contamination prevents the establishment
of initial key contacts between living cells and the actual implant surface. On a long term basis this led to the
formation of connective tissue capsules around implants in stead of direct implant-bone contacts that now are
known to be essential for successful long term functional control of implant loading and prevention of implanttissue infections.
This paper present an overview of these problems as well as recent data supporting the view that the
establishment of undisturbed, initial contacts between living cells and implant materials with defined surface
chemical characteristics is an absolute prerequisite for long term clinical success with modern dental implant
systems. It will also point on certain surface chemical problems associated with the efficacy of in situ hygiene
procedures for patients wearing dental implants.
13-26
Studies on the Stability of the Choramphenicol in the Microemulsion-based Ocular Drug
Delivery Systems
LIQIANG ZHENG, Key Laboratory of Colloid and Interface Chemistry, Shandong University,
Ministry of Education, Jinan, P. R. China. lqzheng@sdu.edu.cn
Two microemulsion systems which were composed of Span20+Tween20＋isopropyl
palmitate+H2O and Span20/80+Tween20/80＋n-butanol＋H2O＋isopropyl palmitate /isopropyl
myristate were investigated as potential drug delivery systems for eye drops. Effects of
choramphenicol, normal saline, sodium hyaluronate and various oils on the phase behavior were
studied. The phase transition was investigated using the electrical conductivity measurements.
The choramphenicol is used to treat the eye diseases such as trachoma and keratitis. However,
this drug in the common eye drops hydrolyzes very easily. The main product of the hydrolysis is
glycol. Here, the choramphenicol was trapped into the oil-in-water microemulsions, its stability
was investigated by HPLC assays in the accelerated experiments of three months. The location
of the choramphenicol molecules in the microemulsion formulations was determined by means
of 1H NMR spectroscopy and dynamic light scattering (DLS). The results of HPLC revealed that
the content of the glycols in the microemulsion formulation was much lower than that in the
commercial eye drops at the end of the accelerated experiments. It implied that the stability of
the choramphenicol in the microemulsion formulations is increased remarkably. The results of
NMR and DLS confirmed that the choramphenicol molecules should be trapped into the
hydrophilic shell of the microemulsion drops, which were composed of many oxyethylene
groups. It was this reason that enabled the choramphenicol molecules in the microemulsions to
be screened from the bulk water and its stability to be increased remarkably.
13-27
Application of Phase Studies for the Formulation of High Ionic Strength Antiperspirant
Products
ZHUNING MA, Richard Brucks, Unilever HPC-USA, 3100 Golf Road, Rolling Meadows, IL,
zhuning.ma@unilever.com
Antiperspirant products are a very large personal care category, 90% of the American population
use antiperspirants every day. The products on the markets are in different forms, such as solid
sticks, soft solids, gels, sprays, aerosols, creams and roll-ons. From a colloid chemistry point of
view, formulations can be emulsions, microemulsions, co-solvent systems or solid particle
suspensions with or without structurants or polymers.
Aluminum salts are the main active ingredients in antiperspirant formulations. When a high salt
concentration is involved in making a formulation, the phase behavior of the systems is highly
impacted. In this presentation, we will introduce basic knowledge concerning antiperspirant
products and how to use phase studies to reach desirable formulation for consumer products.
13-28
Salicylic Acid Vesicle Solutions, Emulsions and their Combinations.
ABEER AL BAWAB1, Stig E. Friberg2, 1Chemistry Department, Faculty of Science, University
of Jordan, Amman 11942, Jordan, 2Chemistry Department, University of Virginia,
Charlottesville,VA, drabeer@ju.edu.jo.
The phase diagrams were determined of salicylic acid as beta hydroxy acid and to be compared
with series of hydroxy acids such as lactic acid, isohexanoic hydroxy acid and some water
soluble acids such as malic, tartaric and citric acid. The acids were combined with water, a
nonionic surfactant and a paraffinic oil to outline the influence of the hydroxyl acids on the
structure in a model for a skin lotion. The colloidal structures of beta carboxylic acid topical
formulations were determined and the changes during evaporation after applications were
estimated from phase diagrams.
The results showed that; the influence of the acid to be similar to that of the oil, but that the
difference in chain length between the alpha acids had only insignificant influence,
the significant difference between salicylic acid on one hand and three water soluble acids;
malic, tartaric and citric acid, on the other, the water soluble acids showed an increase in the
acid concentration in the water to levels that must be considered definitely harmful, while
salicylic acid showed no increase in concentration in the individual phases.
13-29
Theoretical Study on Synergisms of Surfactant Mixtures
ZHENG-WU WANG1,2, Zhong-Ni Wang2, Jun Xu2, and Ganzuo Li2, 1School of Chemical and
Material Engineering, Southern Yangtze University, 170 Huihe Rd, Wuxi, P.R. China, and 2Key
Lab of Colloid and Interface Chemistry for State Education Ministry, Shandong University,
Jinan, P.R. CHINA, wangz.w.@263.net
By appointing the ideal mixture system of surfactants as the standard of comparison, synergisms
in surface tension reduction efficiency and in mixed micelle formation of binary surfactant
mixtures in aqueous solution have been redefined. The conditions and the corresponding
optimum point values of these two kinds of synergism also have been deduced on the bases of
the regular solution theory and the ideal solution theory. The conclusions have enlarged
reasonably the scope of synergism theory proposed by Rosen and his coworkers.
13-30
Colloid and Surface Science in Consumer Product Development
FRAN E. LOCKWOOD, Z. George Zhang, The Valvoline Company, P.O. Box 14000,
Lexington, KY, felockwood@ashland.com
Colloid and surface science plays a key role in product development at many Consumer Products
companies. This talk will focus on the consumer products designed for the automotive
aftermarket: lubricants, chemicals, and appearance products. These products have evolved
dramatically due to empirical and scientific advances in the field. Lubricants today are engine
tested under conditions where suspended soot and particulates may exceed 8 % by weight.
Appearance products, such as car wash, automotive waxes, tire shines and wheel cleaners, etc.,
have benefited from an array of advances in detergency, emulsion and microemulsion
technology, and colloidal dispersion technology. Automotive chemicals, e.g. fuel system
cleaners, have benefited from new detergent technology as well. The impact of colloid and
surface science on these consumer products is explained, pointing out some of the key advances.
13-31
X-ray Studies of Mixed Surfactant Ordering and Phases at the Water-Oil Interface
Sai Venkatesh Pingali1, Takanori Takiue4, Guangming Luo1, Aleksey M. Tikhonov3, Norihiro
Ikeda5, Makoto Aratono4, MARK L. SCHLOSSMAN1,2, Departments of 1Physics and
2
Chemistry, University of Illinois at Chicago, 845 West Taylor St, Chicago, IL, 3Center for
Advanced Radiation Sources, University of Chicago, and Brookhaven National Laboratory,
National Synchrotron Light Source, Beamline X19C, Upton, NY4Department of Chemistry,
Faculty of Sciences, Kyushu University, Fukuok, Japan, 5Department of Environment Science,
Faculty of Human Environmental Science, Fukuoka Women’s University, Fukuoka, Japan.
schloss@uic.edu
X-ray reflectivity is used to study ordering on the Angstrom scale of a monolayer of surfactants
self-assembled at the liquid-liquid interface between bulk water and hexane. This technique
determines the electron density as a function of depth through the interface. Studies of the
interface between water and single surfactant hexane solutions of either CH3(CH2)19OH or
CF3(CF2)7(CH2)2OH demonstrate the liquid order of the hydrocarbon monolayer or the solid
order of the fluorocarbon layer, as well as phase changes with temperature. Interfacial tension
and x-ray studies of the interface between water and mixed solutions of these surfactants in
hexane determine the phase diagram, and the molecular ordering of the phases, as a function of
temperature for four different surfactant compositions. An unusual feature is the phase change
from a liquid to a solid monolayer that occurs with increasing temperature. A simple model
predicts the interfacial coverage as a function of temperature for the mixed surfactant system
from the behavior of the single surfactant systems.
13-32
Monolayer Phase Morphology Induced by Bulk Flow
A. H. HIRSA1, Jonathan J.F. Leung1, M. J. Vogel2, and J. M. Lopez3, 1Mechanical Engineering,
Rensselaer Polytechnic Institute, Troy, NY, 2Chemical and Bimolecular Engineering, Cornell
University, Ithaca, NY, 3Mathematics, Arizona State University, Tempe, AZ, hirsaa@rpi.edu
Effects of bulk flow on Langmuir monolayers are examined in open flow systems (rectangular
cavities and cylinders) driven by the motion of the floor. The air/water interface covered by an
insoluble monolayer (vitamin K1) is studied using a Brewster angle microscope (BAM) system
that utilizes a pulsed laser to image the coexisting phase domains on the fast-moving surface.
The flow field is measured using a digital particle image velocimetry system. A range of flow
conditions is considered where the Reynolds number is large (large flow inertia) yet the flow is
essentially two-dimensional (planar or axisymmetric). Macroscale flows can induce various
mesoscale phase behaviors, such as fragmentation of phase domains. Recent results from this
and other groups show that coexisting phase domains, observed over a wide range of monolayer
states, have profound effects on the (macroscopic) response of monolayers to flow. We examine
the effects of shearing and dilating flows on the coexisting phase domains with the aid of
numerical results obtained using the Navier-Stokes equations with Boussinesq-Scriven surface
model. We show that the response of coexisting phases to flow and the resulting morphological
transitions from one phase to another needs to be accounted for when interfacial hydrodynamics
drives the system far from equilibrium.
13-33
Mixed Cationic and Glycoside Surfactants: Investigation of Ternary Phase Diagram and
Predictive Mesoporous Materials Synthesis
R. Xing, S. E. RANKIN, Chemical and Materials Engineering Department, University of
Kentucky, Lexington, KY, srankin@engr.uky.edu.
Mixed surfactant systems have the potential to impart controlled combinations of functionality
and pore structure in mesoporous ceramics. In this instance, we combine a functional glycoside
surfactant with a cationic surfactant that more readily forms liquid crystalline mesophases. The
phase diagram for the ternary system CTAB/H2O/n-Octylβ-D-glucopyranoside (C8G1) at 50 °C
is investigated using polarized optical microscopy. At this temperature, the binary C 8G1/H2O
system forms micellar solutions up to over >70 wt% C8G1, and there is no hexagonal phase.
With the addition of CTAB, we identify a large area of hexagonal phase, as well as cubic,
lamellar and solid surfactant phases. The ternary phase diagram is used to predict the synthesis of
thick mesoporous silica films via a direct liquid crystal templating technique. By changing the
relative concentrations of mixed surfactants as well as inorganic precursor species, mesoporous
silica films can be synthesized with variable glycoside content, and with 2D hexagonal, cubic
and lamellar structures. The domains over which different pore structures are prepared
correspond well with those of the analogous mesophases in the ternary phase diagram if the
hydrophilic inorganic species is assumed to act as an equivalent volume of water.
13-34
Nano-Emulsion Formation by Low-Energy Emulsification Methods and Phase Behavior
C. SOLANS, P. Izquierdo, D. Morales, N. Sadurní, J. Esquena, N. Azemar, M. J. Garcia-Celma,
Institut d’Investigacions Químiques i Ambientals de Barcelona (IIQAB), Consejo Superior de
Investigaciones Científicas (CSIC), Barcelona, Spain, csmqci@cid.csic.es
Emulsions with droplet size in the nanometer scale (typically in the range 20-200 nm) are know
as nano-emulsions, miniemulsions, submicron emulsions, etc. Due to the extremely small droplet
size, nano-emulsions appear transparent or translucent to the naked eye (resembling
microemulsions) and possess stability against sedimentation or creaming. These properties make
nano-emulsions of interest for fundamental studies and for practical applications. In this
communication, our recent work on the formation of nano-emulsions in water/polyethoxylated
nonionic surfactant/oil systems by low-energy emulsification methods will be reported. O/W
nano-emulsions with droplet sizes as low as 20 nm and high kinetic stability have been obtained
either by the PIT method or at constant temperature (by changing the composition). It has been
inferred from phase behavior studies that a requirement for the formation of minimum droplet
size is to achieve a complete solubilization of the oil phase in a bicontinuous microemulsion,
independent of whether the initial phase equilibrium is single or multiphase.
14-01
Growth of Hierarchical Nanostructured Materials via Soft Solution Routes
NELSON S. BELL, Jun Liu, Jim A. Voigt, Julia Hsu, Tom Sounart, Eric Sporke, Sandia
National Laboratories, P.O. Box 5800-1411, Albuquerque, NM, nsbell@sandia.gov
Nanostructured films have numerous applications including wetting, microfluidics, photonics,
and other opto-electronic properties. Solution phase syntheses of nanostructured films provide
the potential for cost effective, large scale manufacturing. In this talk, we will review recent
progress at Sandia National Laboratories in using solution based, bottom-up approaches to
synthesize oriented nanostructured films and complex nanostructures. First, the principles and
applications of heterogeneous nucleation and growth will be highlighted. Next, a hierarchical
growth method we recently developed to control structural ordering in a step wise manner will
be discussed. Large arrays of complex, oriented and ordered architectures have been produced.
Growth directing factors that influence crystalline morphologies will be discussed. Finally, we
will demonstrate the wide applicability of the methods we developed in different systems.
14-02
Rare Earth Doped Nanocomposites for Photonic Applications
JOHN BALLATO†, Dennis Smith‡, Richard E. Riman*, Chun-Wei Chen*, G. Ajith Kumar*,
Center for Optical Materials Science and Engineering Technologies, †School of Materials
Science and Engineering, ‡Department of Chemistry, Clemson University, Anderson, SC,
*Center for Ceramic Research, Rutgers, The State University of New Jersey, Piscataway NJ,
john.ballato@ces.clemson.edu
The proliferation of optical systems for communications, defense, entertainment, automotive,
and display applications has manifested the need for devices that can perform a greater number
of tasks while being increasingly robust, take up less space, and use less power to operate. These
increasingly more stringent requirements continue to spur international research efforts on
materials that exhibit multiple optical functionalities. This talk will focus on approaches to
achieving greater functionality and efficiency through the use of fluoropolymer nanocomposites.
More specifically, theoretical and experimental studies on transparent rare-earth doped halide
nanoparticles in unique fluoropolymer matrices will be presented as will potential applications.
14-03
Preparation of Nanoporous Silica and Sodium Fluoride from Hexafluorosilicic Acid and
Sodium Silicate
JONG-KIL KIM, Jin-Soo Kim, Jin-Koo Park and Ho-Kun Kim, Department of Applied
Chemistry, Hanyang University 2-304, Science and Technology Building 1, 1271 Sa 1 dong,
Ansan, Kyunggi-do, South Korea, pradipsarawade@yahoo.co.in
A process for the preparation of nanoporous silica and recovery of sodium fluoride from
hexafluorosilicic acid and sodium silicate at the different molar ratios was studied. In order to
prepare the appropriate solutions of initial compounds the 25% hexafluorosilicic acid solution
and the 18% sodium silicate solution were used. Obtained nanoporous silica and sodium fluoride
have been investigated by XRD, BET, TGA, EDX and SEM methods
14-04
Top-Down or Bottom-Up: New Approaches for the Fabrication of (Functional) ThreeDimensional Photonic Crystals
G. VON FREYMANN1, S. Wong, M. Deubel1, M. Hermatschweiler1, D. C. Meisel1, M.
Wegener1, N. Tétreault2, E. Vekris2, V. Kitaev2, G. A. Ozin2, 1Institut für Nanotechnologie,
Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germany, 2Department of Chemistry,
University of Toronto, ON, Canada, S. John, Department of Physics, University of Toronto, ON,
Canada, freymann@int.fzk.de
Bottom-up self-assembly of colloidal sub-micron size spheres as well as top-down holographic
laser lithography in photoresists are reliable tools for the inexpensive, large-scale fabrication of
three-dimensional Photonic Crystals. To add functionality to these Photonic Crystals we follow
different approaches: A lithographic method allows for reliable waveguide fabrication inside
colloidal Photonic Crystals, while Direct Laser Writing (DLW) is the method of choice for
holographically fabricated samples.
The crucial step for both methods is the final conversion into high index materials, e.g., silicon.
As conventional silicon chemical-vapor deposition (CVD) can be used for bottom-up templates,
no such technique is available for photoresist-based samples. Here we demonstrate the successful
double-inversion of direct-laser written templates, combining silica and silicon CVD techniques.
Finally, a novel approach for the direct fabrication of three-dimensional Photonic Crystals will
be presented, namely DLW in high index of refraction chalcogenide glasses with subsequent wet
etching of the unexposed areas.
14-05
Colloidal Crystal Based 3-D Chemical Sensors and Optical Waveguides
PAUL V. BRAUN, Assistant Professor, Materials Science and Engineering, University of
Illinois at Urbana-Champaign, IL, pbraun@uiuc.edu
Colloidal materials offer interesting opportunities for scientific exploration and formation of
functional materials and structures. After a brief introduction to the optical properties of
colloidal crystals and photonic band gap materials, I will present our results on synthetic opal
based devices. Device fabrication begins with the self-assembly of silica or polystyrene colloidal
particles into a colloidal crystal, this colloidal crystal is then used to template a periodic 3-D
structure into an optically active material. Colloidal crystals inherently have interesting optical
properties, however by inverting the structure into a functional material, the optical behavior can
be significantly enhanced. Using such an approach, we have created hydrogel inverse opal
chemical and biological sensors. These sensors show rapid (~1 minute) diffusion limited
responses to small changes in pH and glucose concentration, and were designed to have an
optical diffraction based response that is detectable with the naked eye. The mechanical
behavior of these structures turned out to be rather interesting. As the polymer swelled, the
inverse opal transformed from fcc to L11 due to the strain field in the hydrogel inverse opal, and
antiphase boundaries were observed to form. In contrast to photonic based sensors, which only
require periodic structures, for a number of applications, incorporating aperiodic defects on the
wavelength of light into an otherwise periodic structure will be critical. For example, a 3-D
waveguide with a bend radius on the order of the wavelength of light could be created by
embedding a waveguide structure inside of a photonic band gap material. We have been
developing multiphoton polymerization of three-dimensional structures to do exactly this, and
have demonstrated the writing of waveguide structures within colloidal crystals. A number of
issues still must be dealt with to create an optical device, and I will highlight our latest results in
this area.
14-06
Novel Types of Optical Gain Media Based on Photonic Crystals “Activated” with
Semiconductor Nanocrystals
G.R. MASKALY, M.A. Petruska, J. Nanda, I.V. Bezel, N. Liu, R.D. Schaller, H. Htoon, J.M.
Pietryga, V.I. Klimov, Softmatter Nanotechnology and Advanced Spectroscopy Team, C-PCS,
Los Alamos National Laboratory, Los Alamos, NM , maskaly@lanl.gov
The periodic variations of the dielectric constant in photonic crystals (PCs) give rise to photonic
band structures analogous to those for electrons in semiconductors. Near the edges of the
photonic band, the photonic density of states and group velocities are modified. In some cases,
near zero group velocities are obtained leading to very large optical gains. Since PC properties
are wavelength tunable through size variations, their properties can be tailored to match
semiconductor nanocrystals (NCs) emissions, which are tunable across a wide spectral range
through compositional and size variations. Here, we demonstrate NC incorporation into a
variety of PC structures. In one example, we utilize self-assembled opals as a host for NC/solgel (NC/SG) nanocomposites. Despite an order-of-magnitude reduction in the NC volume
fraction versus NC/SG films, we observe a two-fold reduction in the amplified spontaneous
emission (ASE) threshold and an optical gain increase evidenced by the observation of ASE with
a 30-dimensional PC structures on the
optical properties of NC/SG composites. Here, we incorporate the NC/SG material directly into
a one-dimensional PC. The results presented here are steps toward low-threshold NC lasers that
can be excited by a continuous wave source.
14-07
The Rate-controlled Synthesis of Doped Ferroelectric Nanoparticles under
Conditions of Micro/Nanoreactors.
A.V. RAGULYA, A.V. Polotai, Frantsevich Institute for Problems in Materials Science NAS of
Ukraine, 3, Krzhizhanovski St., 03142 Kiev, Ukraine, ragulya@materials.kiev.ua
Synthesis of nanoparticulate materials in micro/nanoscale reactors is widely used as a powerful
and precise technique. One of the possible small-scale reactors is particulate intermediate
product originating from thermal decomposition of unstable precursors. Scaling relationship
between size of reactor and size of the specified nanoparticles is not well-understood one. The
recently developed process, so called rate-controlled synthesis, is considered useful in
manufacturing of nanosized powders from unstable precursors. The reaction rate-controlled
processes (RCP) strongly differ from the conventional synthesis and sintering due to feedback
established between transformation value and instantaneous temperature. During RCP, the
transformation value is the dependent parameter whereas the temperature is the independent
parameter, contrary to conventional processes. The chemical synthesis proceeds through the
competition between new phase nucleation and nuclei growth. Both nucleation and growth have
different thermal activation energies and, therefore, different rate, which is a function of
temperature and heating rate. The competition of mechanisms results in possibility of particle
size control. The rate-controlled mode allows flexible temperature-time regime and refinement of
particles compared to conventional ramp-and-hold regimes. For instance, the rate-controlled
decomposition of unstable precursors of barium titanate, zirconia and lanthanum-strontium
manganate resulted in 1.2-2.0 times decrease of particle size compared to linear heating rate
regimes. The nanosized barium titanate powders, both pure and doped, have been prepared
through the modified Pechini process. The intermediate product of oxalate decomposition was
impregnated with soluble precursors of dopants such as niobia, calcia, yttria and subsequently
co-decomposed until synthesis of doped barium titanate. The morphological transformations
within intermediate resin-like products have been studied by combination of FTIR, RAMAN and
Kawazoe methods. The understanding of internal structure of nanoreactors allowed us to clarify
features of rate-controlled non-linear heating rate synthesis compared with conventional process
of ramp-and-hold.
14-08
Barium Titanate Based Nanocrystalline Ceramics: Preparation and Properties
ANTON V. POLOTAI, Andrey V. Ragulya, Clive A. Randall, Institute of Materials Science
Problems NAS of Ukraine, Kiev, Ukraine, Pennsylvania State University, University Park, PA,
avp10@psu.edu
Barium titanate is the most widely used dielectric material in surface mount components and is
presently under development for the mass production of submicron grain size ceramics. Over the
next ten years, these dimensions will become nanoscale if present trends continue. With this
view, most of the earlier research has focused on the dielectric properties of BaTiO3 and
considered these properties to enhance volumetric efficiency in multilayer ceramic capacitors.
One of the major unknowns in these materials is the influence that nanosized grains may have on
the reliability of future devices, which is typically controlled by the ionic migration of point
defects under a direct bias. The production of fully dense nanocrystalline barium titanate
ceramics is a difficult task due to enhanced grain growth during the final stage of sintering. To
win this competition between densification and grain growth, the right combination of different
factors should exist, such as powder particle size and pore size distribution in green body,
sintering schedule and sintering atmosphere, and dopant type and dopant distribution. This work
presents results of rate-controlled synthesis and sintering of doped barium titanate, as well as the
size effect and its relation to reliability and dielectric properties. It is shown that rate-controlled
synthesis by decomposition of thermal unstable precursors gives weakly agglomerated powder
with an average particle size around 20 nm, which can be easily doped by modified sol-gel
technique. Combining pressureless rate-controlled sintering with controlled atmosphere
treatments and effective dopant concentrations yields a nano-grained fully dense ceramic with a
grain size of less than 100 nm, with a 4÷5 factor of grain growth, which is 3÷5 times less than in
traditional sintering modes. The lifetime and dielectric properties are studied based on grain size
and dopant concentration. The prospects of using these results in multilayer ceramic capacitor
technologies are discussed.
14-09
Nanoparticles as Functional Building Blocks: Size, Shape and Composition Control and
Property
Xiaowei Teng, Yong Wang, Xinyi Liang, Justin Galloway, HONG YANG, Department of
Chemical Engineering, University of Rochester, Gavett Hall 206, Rochester, NY,
ongyang@che.rochester.edu
Size, size distribution, shape and composition control of sphere, rod and multipods nanocrystals
is pivotal in the development of new multifunctional nanomaterials. In this presentation, I will
discuss our recent progress in the following areas: 1) size, shape (including monodisperse
nanorods, cubes and multipods) and composition control of metals, metal alloys and metal
oxides in both conventional solvents and ionic liquids; 2) composition and property of FePt and
other alloy-containing magnetic nanocomposites made from core-shell nanoparticles; and 3) the
electrode catalytic property of Pt-containing nanoparticles. This talk will cover several classes of
nanomaterials including Pt, Ag, PtM (M=Co, Fe and Ni), Fe2O3 and a variety of magnetic coreshell nanoparticles. The emphases are on our understanding and the strategies on the controlled
growth of colloidal nanocrystals, and the design of functional materials from nanoparticle
building blocks, which possess interesting magnetic and electro-catalytic properties.
14-10
Alkaline Modified Calcium Doped Lead Titanate Film Humidity Sensor Formed Using SolGel Method
LOUISE J.B. LIU, Zhi-Min Wang, College of Chemistry and Chemical Engineering,
Heilongjiang University, Harbin, P. R. China, jlouise@clarkson.edu
This research encompassed the fabrication, microstructural characterization, and moisture
sensitivity of an alkaline modified, calcium doped, lead titanate thin film humidity sensing
device. The active component for the humidity sensor is based on a LiyCaxPb1-xTiO3 (Li-CPT)
ceramic (x = 0.35 to 0.50, y = 0.005 to 0.01). Films of Li-CPT were prepared by a sol-gel, spincoating technique, and then followed by sintering at 550 to 900 oC for one hour. The films were
structurally characterized by x-ray powder diffraction (PXRD), scanning electron microscopy
(SEM), transmission electron microscopy (TEM), magnetic resonance force microscopy (MFM),
and Raman spectroscopy (RS). Characterization results indicated the synthesized films were
composed of a single perovskite phase with crystallite particles on the order of 30 – 50 nm.
Humidity sensing measurement had been performed for Li-CPT using resistance measurements
at different relative humidity () range of 8% to 93%RH at room temperature. The variations of
resistance values (R) were higher than three orders of magnitude over the working relative
humidity range. The curves of Log R versus  displayed excellent linearity, high sensitivity,
minimal hysteresis and rapid response to the humidity change.
14-11
Dynamics of the Electrohydrodynamic Patterning of Thin Polymer Films
NING WU, William B. Russel, Department of Chemical Engineering, Princeton University,
Princeton, NJ, nwu@princeton.edu
We perform one and two-dimensional simulations of an electrohydrodynamic patterning process
for a mask-air gap-polymer-substrate sandwich, which is a newly discovered patterning
phenomenon. The simulations help us identify the intrinsic pattern resulting from nonlinear
interactions to be hexagonal when the mask is unpatterned, consistent with experimental
observations. The size of microstructures, periodicity and time for formation agree well with the
experimental data. The dynamic evolution of the thin polymer layer under a patterned mask
shows that the pillars start to form from corners, propagate along edges and then grow inwards.
This growth sequence, identical to experimental observations, creates a square pattern under a
square mask, a hexagonal pattern under a triangular mask, etc. Besides the hexagonal pattern,
simulations indicate the conditions under which various different patterns that have been
observed in experiments should form. The dynamic simulations are very helpful in
understanding of the nonlinear dynamics of the patterning process, predicting the final pattern
formation under different conditions, and providing insights for future experimental design.
14-12
Shape-Controlled Synthesis of Metallic Nanostructures
YOUNAN XIA, Benjamin Wiley, Jingyi Chen and Yujie Xiong, Department of Chemistry,
University of Washington, Seattle, WA , E-mail : xia@chem.washington.edu
Future nanotechnology applications, either in electronics, photonics, catalysis, or medicine,
require nanostructure building blocks. I will present a solution phase synthesis that produces
large quantities of silver, gold, platinum, and palladium nanostructures with controlled size,
shape, monodispersity, and crystallinity. Some example nanostructures include silver nanowires
and nanocubes, hollow gold nanotubes and nanocages, platinum nanowires and multipods, and
palladium nanocubes and nanocages. By controlling nanostructure size and shape, one can tailor
the photonic, plasmonic, electronic, and catalytic properties of metallic nanostructures for a
given application.
14-13
Dynamic Tuning of Photoluminescent Dyes in Crystalline Colloidal Arrays
Justin R. Lawrence, Goo Hwan Shim, Ping Jiang, Moon Gyu Han, Yurong Ying, STEPHEN H.
FOULGER, School of Materials Science & Engineering, Clemson University,
foulger@clemson.edu
A number of people in the group have been working on approaches to dynamically (i.e. in real
time) tune the photoluminescent spectrum of dyes localized on crystalline colloidal arrays.
Though a number of experimental studies have studied the suppression of the spontaneous
emission of photoluminescent (PL) materials at frequencies inside the photonic bandgap of
ordered dielectric structures, the majority of these experimental efforts have focused on sterically
packed colloidal crystals composed of dye-labeled particles. Though these systems have offered
a number of insights into this class of materials and have established that the emission spectrum
of a dye may be controlled by the photonic lattice parameter, this control is usually exercised by
fabricating samples of different particle diameters to alter the rejection wavelength.
The ability to dynamically (i.e., in real time) tune the emission characteristics of the dye through
an in-situ modification of the rejection wavelength has not been previously demonstrated in
colloidally-based crystals.
To this end, we focus on the exploitation of mechanochromic tuning to modify the emission
spectra of hydrogel-encapsulated crystalline colloidal arrays composed of electrostatically selfassembled monodisperse polystyrene particles coated with the photoluminescent dye
Rhodamine-B. The broad rejection wavelength tuning range, relatively narrow bandwidths, and
non-hysteretic nature of the mechanochromism of these electrostatically based colloidal crystals
suggest that these systems can be exploited to tune the emission characteristics of an PL dye
coupled to a photonic crystal in a slew of optical/photonic based applications. The variation in
the PL spectra of the system is presented in the adjacent graph as a stop band is
mechanochromically tuned through the emission range; the approximate position of the rejection
wavelength is indicated with the arrows.
14-14
Driving Tomorrow’s Functional Electronics and Optics With Designer Nanopowders and
Nanostructures
R. E. RIMAN, G.A. Rossetti, Rutgers, The State University of New Jersey, Department of
Ceramic and Materials Engineering, 607 Taylor Road, Piscataway, NJ, riman@rci.rutgers.edu
Recent progress in the chemical synthesis of nanomaterials has created new opportunities for the
application of ceramics in advanced structures and devices. Our laboratory is focused on
developing low-cost and robust methods for the synthesis and processing of nanomaterials and
on establishing structure-property relationships at the nanometer length scale. Hydrothermal
crystallization is known to be a highly flexible process to prepare nanopowders and
nanostructured films. Methods for engineering hydrothermal crystallization processes are being
developed using traditional fundamental approaches based on thermodynamic and kinetic
principles. However, the non-classical mechanism of hydrothermal crystallization has brought
forward the importance of non-thermodynamic variables such as fluid hydrodynamics and
precursor characteristics. These variables provide additional degrees of freedom for controlling
the physical and chemical characteristics of designer particulates. Efforts are being dedicated
towards understanding crystallization mechanisms and applying that knowledge to design and
construct unique reactor systems. The availability of designer particulates enables new classes of
functional materials not accessible with conventional commercial ceramic powder processes.
For instance, various families of infrared optics based on transparent halide nanocomposites
would not be possible without the availability of nanoparticles that can be dispersed at length
scales below 100-nm. Dielectric materials based on titania or barium titanate at the 1-µm length
scale require particle sizes less than 200-nm. However, the production of uniform and
dispersible powders alone is insufficient to enable the fabrication of functional materials.
Appropriate mixing and particle assembly methods are needed and being developed to address
the homogeneity length scale requirements, with an emphasis on continuous processing. The
ability to create advanced materials with controlled nanostructure has generated a technology
pull for computational design of materials. Examples illustrating the steps along the path from
particle synthesis to functional materials will be presented for the specific case of new dielectric
and optical nanocomposites.
14-15
Engineering the Forces Between Nanocolloids: Challenges and Opportunities
DARRELL VELEGOL, Department of Chemical Engineering, The Pennsylvania State
University, 111 Fenske Lab., University Park, PAy, velego@psu.edu
Bottom-up assembly of nanocolloids depends in large part on the forces between particles.
Some forces – like the use of DNA as a “selective glue” – cause a desirable “directed” motion.
But other forces – especially the van der Waaals (VDW) forces – cause a random and
nonspecific aggregation of particles. A critical goal then is to minimize these nonspecific forces
between particles so that aggregation occurs only by design. Traditional methods for calculating
and measuring VDW forces between particles are not applicable to nanocolloids. In this talk we
describe how we use Axilrod-Teller-Muto theory to help us calculate VDW forces between
nanocolloids, and we will discuss our current approaches (e.g., particle force light scattering) to
measuring interparticle forces for polystyrene and silica nanocolloids. The focus of the talk will
be on bottlenecks to predicting nanocolloidal forces, possibilities for better models, and
opportunities for bottom-up assembly.
14-16
Preparation and Properties of “Raspberry”-Type Colloidal Building Blocks of ZnS and
Fluorescent Core-Shell Silica Nanoparticles
STEPHANIE H. LEE*, Ian D. Hosein*, Valerie L. Anderson+, Victoria D. Crockett||, Watt W.
Webb+,
Ulrich
B.
Wiesner*,
Chekesha
M.
Liddell*,
+
*Department of Materials Science and Engineering, Cornell University, Ithaca, NY, School of
Applied and Engineering Physics, Cornell University, Ithaca, NY, ||Department of Chemistry,
Tougaloo College, Tougaloo, MS, cliddell@ccmr.cornell.edu
A synthetic route to incorporate high-brightness core-shell silica nanoparticles (CU Dots 2030nm) onto high-refractive index (n) ZnS colloids in a “raspberry” configuration is
demonstrated. Motivation for this work lies in the promise of phenomena such as enhanced nonlinear optical properties leading to ultrafast switching in 3-D photonic crystals with active lightemitting sources. Previous approaches involved either infiltration of a low-n colloidal template
with quantum dots or surface modification of such colloids with dye molecules. In the former
case tunability at the single particle level is lost, while in the latter, the index contrast is
insufficient to promote bandgaps. For the present work, CU Dots and a thin layer of ZnS are cocondensed onto ZnS colloids via the thermal decomposition of thioacetamide in the presence of
metal salt. The fluorescent high-n building blocks (200nm-2m) exhibit complete and uniform
“monolayer” coverage without a decrease in monodispersity, and are suitable for assembly into
3-D structures. Incorporating nanoparticles in the raspberry configuration also provides potential
for brightness enhancement by avoiding quenching of neighboring dye molecules. The
preparation and characterization of these colloids will be highlighted along with preliminary
optical measurements of their assembly, including fluorescence microscopy, excitation-emission
fluorescence spectroscopy and transmission spectroscopy.
11-17
High-Resolution, High-Sensitivity Particle Size Analysis of Concentrated CMP Slurries and
other Nanoparticle Systems using the New Techniques of Focused Light Extinction and
Scattering
D.F. NICOLI, P. Toumbas, Y.J. Chang, J.S. Wu, K. Hasapidis, Particle Sizing Systems Inc.,
Santa Barbara, CA, dave@pssnicomp.com
The technique of single-particle optical sensing (SPOS) is effective for assessing the quality of
oxide “CMP” slurries used for semiconductor processing, ink-jet toners/pigments and a variety
of other nanoparticle-based dispersions and suspensions. The large-diameter “tail” of the
particle size distribution (PSD) can be measured effectively by combining the methods of light
extinction (LE) and scattering (LS), called “LE+LS” (Pat.). However, this approach requires
extensive sample dilution to achieve high sensitivity (> 0.5-um) and avoid PSD artifacts due to
particle coincidences and background scattering. New techniques, called focused extinction
(FX) and scattering (FS), have recently been developed (Pat.), which utilize a much smaller
active sensing zone and novel signal processing methods. The resulting FX sensor requires
much less sample dilution (often none), while still achieving excellent small-particle sensitivity
not possible using conventional LE technology. The companion LS sensor produces PSD results
of unprecedented resolution and sensitivity for particles as small as 0.1-um and concentrations
exceeding 10 million/ml. The combined FX and FS capabilities permit accurate particle size
measurement of many submicron systems that are poorly characterized using laser diffraction
and other ensemble techniques.
14-18
Colloidal Self-Assembly, Multibeam Holography and Photonic Crystals
PIERRE WILTZIUS, Beckman Institute for Advanced Science and Technology, Materials
Science and Engineering Department and Physics Department University of Illinois at UrbanaChampaign, 405 North Mathews, Urbana, IL, wiltzius@uiuc.edu
Photonic crystals are materials that allow the manipulation of light in new and unexpected ways.
Semiconducting materials played a tremendous role in microelectronics and we expect photonic
crystals to revolutionize the world of microphotonics in a similar way. Colloidal self-assembly
and multi-beam interference lithography are great tools to build crystals with interesting optical
properties. I will review some recent progress towards constructing photonic band-gap materials.
14-19
Synthesis and Characterization of Polymer Encapsulated Nanoparticles for
Microelectronic Applications
PRASHANT MESHRAM, Richard Partch, Center for Advanced Materials Processing and
Department of Chemistry, Clarkson University, Potsdam, NY,
rpartch@clarkson.edu; meshraps@clarkson.edu
There are two well-researched methods for constructing the core-shell morphology of particles.
The shell can be produced by adsorption of preformed macromolecules onto core surfaces by
electrostatic or by non-solvent deposition methods. An alternate method involves mixing core
particles with monomers and then initiating polymerization. This procedure is more favorable for
obtaining a uniform coating of each particle because of the substantially higher accessibility of t
he active surface of cores for molecules of a monomer compared to the corresponding
macromolecules. However, the formation of an organic shell on extremely small silica
nanoparticles (~ 20 nm) by the same method has received little attention. In the present work; we
demonstrate a process of coating of such small colloidal silica particles with polymers in two
layers; the first layer is PDVB (polydivinylbenzene) and the second layer is PHEMA (poly2hydroxyethylmetha-crylate). Results of several time based adsorption experiments are presented
to verify the hypothesis of monomer adsorption on inorganic core with and without initiator. The
presence of polymer encapsulating the silica surface was determined by FTIR spectroscopy,
transmission electron microscopy(TEM) and ALV particle sizing instruments; while the amount
of coated polymer on silica surface was assessed by thermogravimetric analysis(TGA). These
polymer coated particles can be used as soft abrasives in CMP application to minimize defects.
14-20
Enlargement of Dye-sensitized Solar Cell by Using High Performance Transparent
Electrode and Nano-porous TiO2 Film
SHOJI KANEKO, Masayuki Okuya*, G.R. Asoka Kumara*, SPD Laboratory, Innovative Joint
Research Center and *Department of Materials Science and Technology, Shizuoka University,
Johoku, Hamamatsu, Japan, kaneko@cjr.shizuoka.ac.jp.
Dye-sensitized photoelectrochemical cell based on nano-porous semiconductor materials are
gaining much attention as a promising solar energy conversion system. We have successfully
developed a spray pyrolysis deposition technique to prepare high transparent conducting oxide
and nano-structured TiO2 films for the fabrication of large-area dye-sensitized solar cell.
Transparent conducting oxide film, in which tin-doped indium oxide (ITO) inner layer was
covered with fluorine-doped tin oxide (FTO) outer layer, gave low resistivity 1.3 x 10-4 W cm
and high optical transmittance about 80 %. TiO2 film, which is formed mainly from a mixed
solution of Ti-containing compound and TiO2 sol, has much higher light-scattering properties
and dye adsorption porosities. A solar cell consisted of dye-impregnated TiO2 porous film of an
about 12 mm thickness and of a 7 x 4 cm2 active area, Pt counter electrode, and redox
electrolyte. This solar cell showed short-circuit photocurrent (Isc) 9.89 mA cm-2, open-circuit
voltage (Voc) 735 mV in AM-1.5 simulated sunlight (100 mW cm-2) with an efficiency of
5.08%.
14-21
Atomically-Flat Nanosurfaces: Flat Gold Nanoparticles as a Novel Substrate for STM and
Photonic Studies
D. H. Dahanayaka, J. X. Wang, S. Hosain, W. D. Tennyson, D. W. Kelle, D. J. Wasielewski, G.
D. Lian, L. A. BUMM, Center for Semiconductor Physics in Nanostructures, Department of
Physics and Astronomy, University of Oklahoma, Norman, OK, bumm@nhn.ou.edu
Flat gold nanoparticles (FGNPs) can be used as atomically-flat gold substrates for STM studies.
When supported on indium tin oxide (ITO) coated glass the FGNPs can also be used as
atomically-flat photonic substrates. Transmission electron microscopy (TEM) shows that
FGNPs can be prepared 100–500 nm across with shapes that range from triangular to hexagonal
with thicknesses of 15-25 nm. Dark-field optical microscopy is a convenient method for
evaluating the FGNP arrays because the FGNPs and spherical gold nanoparticles are
distinguished easily by their plasmon resonance spectra. Scanning tunneling microscopy (STM)
reveals atomically flat terraces on the large {111} FGNP facets, which are flat to a few atomic
layers over entire surface. No stepping (rounding) of the facet is observed even near the edges.
STM images demonstrate that well-ordered alkanethiol self-assembled monolayers (SAMs) form
on the FGNP/ITO substrates, thus they are excellent substrates for molecularly resolved STM
imaging. Our results indicate that our FGNPs grow as single crystals, rather than by aggregation
of smaller nanoparticles. An optimized method for growing the FGNPs and for depositing them
on ITO coated glass with a high particle density is presented.
14-22
14-23
Two Dimensional Arrangement of Gold Particles Less Than 10nm
LONG JIANG, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080,
P.R.China; Fax: 86-10-82612084, jiangl@iccas.ac.cn
Monodisperse nanogold particles 2-5nm in diameter with standard deviation less than 0.4 have
been prepared by using different methods. Many approaches to produce a homogeneous 2D
arrangement have been attempted. A well ordered packing domain with area more than 1 m2
has been achieved on liquid and solid substrates by capillary force. Compare with the result
which we obtained before, the area free from voids and quality of packing is much improved.
The controlled factors and possible mechanism have been examined and discussed.
14-23
Computer Simulation Study on Behaviors of Surfactants at the Liquid/Liquid Interface
YING LI*, Feng-Lan Dong, Xiu-Juan He, Key Lab for Colloid and Interface Chemistry of State
Education Ministry, Shandong University, Jinan 250100, P. R.China, yingli@sdu.edu.cn
Behaviors of surfactants at the interface play an important role in the industrial application, such
as oil extraction, deterging process and material preparation. However, the detail information of
interfacial region on a molecular level is scarce. Recently, computer simulation has become an
effective tool for the study of complex interfacial systems on a detail molecular level, such as
molecular dynamics (MD) simulations. However, the time and length scales accessible to
ordinary MD simulations are not large enough to study some phenomena in surfactant system.
Therefore, a mesoscopic level simulation named dissipative particle dynamics (DPD) is used to
investigate the behaviors of surfactants at the water/oil interface.
Dissipative particle dynamics simulation bridges the gap between atomistic and mesoscopic
simulations. The simulation strategy is to regard clusters of atoms as fluid particles or beads,
some of which are connected by harmonic spring. Soft spherical beads interact through an
effective pairwise interaction potential obtained from detailed atomistic molecular dynamics
simulations, and thermally equilibrate through hydrodynamics.
The orientation of sodium dodecylsulfonate (DDS) and sodium dodecylsulfate (SDS) adsorbed at
the water/carbon tetrachloride interface has been studied by considering the variation of root
mean square (RMS) end-to-end distances of surfactants. An increase in the interface
concentration of surfactants results in the increase in the orientation of surfactants before
reaching a full monolayer. Strong hydrophilic head groups are beneficial to form a well-ordered
configuration and appropriate salts make surfactant molecules more stretched and ordered, which
may be interpreted as a reduction on gauche defects for them.
The synergistic effects of mixed surfactants sodium dodecylbenzene sulphonate (SDBS) and
Triton X-100 (TX-100) at the oil/water interface has also been investingated. With the decrease
in aHH and aW E , SDBS and TX-100 are driven to adsorb more at the interface and can decrease
sharply the interfacial tension of the mixed system. Also we have observed that some cavities
between SDBS clusters at the interface can be filled with TX-100 clusters. The inhomogeneous
distribution helps to understand the mechanism of the synergism interaction and the decrease in
the interfacial tension.
Therefore, computer simulation method might be an attractive method to provide effective
information about behaviors of surfactants on a mesoscopic level.
14-24
14-25
High Dielectric Properties Ofnm-sized Barium Titanate Crystallites
and its Origin
S. WADA, T. Hoshina, H. Yasuno, S.-M. Nam, H. Kakemoto, M. Yashima, T. Tsurumi, Tokyo
Institute of Technology, Department of Metallurgy and Ceramic Science, 2-12-1 Ookayama,
Meguro-ku, Tokyo, Japan, swada@ceram.titech.ac.jp
BaTiO3 crystallites with various particle sizes from 20 to 1000 nm were prepared by the
modified 2-step thermal decomposition method of barium titanyl oxalate. Investigation of
impurity in these particles using both TG-DTAand FT-IR measurements revealed that no
impurity was detected in the BaTiO3 lattice while hydroxyl and carbonate groups were detected
only on the surface. Moreover, their relative densities werealways above 99%. The dielectric
constants of these powders were measured using suspensions by a modified powder dielectric
measurement method. As a result, the dielectric constant of BaTiO3 particles with a size of
around 140 nm exhibited a maximum of around 6,000. Thus, we discussed the origin of high
dielectric constant around 6,000 for BaTiO3 particles with a size of around 140nm. The crystal
structure of the BaTiO3 particles with sizes below 100 nm was always assigned to cubic m-3m
by a conventional X-ray diffraction measurement because of significant line broadening. Thus,
using a synchrotron radiation X-ray powder experiment with imaging plate, the crystal structure
of the BaTiO3 particles with sizes below 100 nm was investigate from 25? to 300?. As a result,
in the BaTiO3 particles with sizes over 40 nm, itwas confirmed that their crystal structure at 25?
was assigned to 4mm. This means that the c/a ratio decreased with decreasing particle sizes
from 1000 nm to 40 nm. On the other hand, the local and dynamic crystal structure of the
BaTiO3 particles with sizes below 1000 nm was assigned to tetragonal 4mm by a Raman
scattering measurement. It should be noted that in the particlesize with a maximum dielectric
constant of 6,000, its c/a ratio wassmaller than 1.011 as the same as single crystal value.
Finally, to explain the origin of high dielectric constant, the model related to superparaelectric
behavior was proposed.
14-26
Atomic Layer Deposition on Submicron ZrO2 and BaTiO3 Particles
BEAU B. BURTON, Steven M. George, Department of Chemistry and Biochemistry
University of Colorado, Boulder, CO, Beau.Burton@colorado.edu
BaTiO3 is a ferroelectric material with a large dielectric constant that is critical in the fabrication
of multilayer ceramic capacitors (MLCs). Because of the ultrathin thickness of the dielectric
layers in MLCs, submicron BaTiO3 particles are used to fabricate the dielectric layers. In the
past, BaTiO3 particles could be mixed with other impurity particles to improve the properties of
the dielectric layer. This approach is becoming increasingly difficult because the dielectric layer
thickness is approaching the size of the individual particles. One solution is to coat the BaTiO 3
particles uniformly with ultrathin films to achieve homogeneous behavior in the thin dielectric
layer.
Thin films can be deposited on particles using atomic layer deposition (ALD) techniques. ALD
is performed using sequential, self-limiting surface reactions. ALD can achieve atomic layer
controlled and conformal film growth. Our recent work has shown that ALD techniques can
deposit conformal and atomic layer controlled films on various particles. Our examples in the
literature are Al2O3 ALD on BN particles, SiO2 ALD on BN particles and BN ALD on ZrO2
particles. We have also recently demonstrated catalytic SiO2 ALD on ZrO2 and BaTiO3 particles
and ZnO ALD on ZrO2 and BaTiO3 particles. Our current research has focused on improving
SiO2 ALD on ZrO2 and BaTiO3 particles and developing new surface chemistry for Y2O3 ALD
on ZrO2 and BaTiO3 particles. ZrO2 particles are employed as model particles and yield
excellent transmission electron microscopy (TEM) images.
The atomic layer deposition (ALD) of SiO2 is very challenging. SiO2 ALD can be accomplished
using SiCl4 and H2O reactants at 600-800 K with large exposures of ~109 L or using TEOS and
H2O reactants at room temperature employing NH3 as a catalyst with large reactant exposures of
~109 L. Recently, we have observed much more efficient SiO2 ALD with HSi[N(CH3)2]3 and
H2O2 reactant exposures. HSi[N(CH3)2]3 is tris-dimethylaminosilane (Tris-DMAS). SiO2 ALD
was studied using Fourier transform infrared (FTIR) spectroscopy to monitor the surface
chemistry. The exposures required for the Tris-DMAS and H2O2 reactions were ~106L and
~107L, respectively. The SiO2 thin films were deposited at temperatures ranging from 525-825
K. The maximum growth rate of 1.9 Å/cycle at 825 K was determined by measuring the SiO 2
film thickness by TEM. This talk will discuss our results for SiO2 ALD and new results for
Y2O3 ALD on ZrO2 and BaTiO3 particles.
14-27
Preparation and Characterization of the Cobalt Titanate CoTiO3 Nanoparticles by
Evaporation-Induced Self-Assembly
G. W. ZHOU1, Y. S. Kang2, 1. School of Light Chemical and Environmental Engineering,
Shandong Institute of Light Industry, Jinan, China; 2. Department of Chemistry, Pukyong
National University, Daeyeon-3-dong, Nam-gu, Pusan, Korea, guoweizhou@hotmail.com
The nanostructured photocatalyst of cobalt titanate, CoTiO3 has been prepared by oxidation of
Co(OH)2 using titanium dioxide TiO2 powder (P-25) as base material in
cetyltrimethylammonium bromide (CTAB) micelle solutions, then followed the calcinations of
the produced powders. These nanoparticles were investigated with X-ray powder diffraction
(XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Xray photoelectron spectroscopy (XPS) and thermogravimetric/differential thermal analysis
(TGA/DTA) to determine the crystallite size and the phase composition. The spectroscopic
characterizations of these nanoparticles were also down with UV-Vis spectroscopy and FTRaman spectroscopy. XRD patterns show that CoTiO3 phase was formed at calcinations
temperature above 600 0C. The UV-Vis results showed that the CoTiO3 nanoparticles have
significant red shift to the visible region (400-700 nm). The new absorption peaks in FT-Raman
also show the formation of Ti-O-Co bonds at above 600 0C and just not the mixtures of titanium
dioxide with cobalt oxides.
14-28
Shrinking Composite Core-Shell Nanoparticles for Chemical Mechanical Planarization
SILVIA ARMINI*†,‡, Salvador Eslava†,‡, Caroline Whelan†, Valentina Terzieva†, Karen Maex†,‡,
†
IMEC, Kapeldreef 75, B-3001 Leuven, Belgium. ‡Department of Electrical Engineering,
Katholieke Universiteit Leuven, Kasteelpark Arenberg 1, B-3001 Heverlee, Belgium., IMEC,
SPDT/ADRT Division, Kapeldreef 75, B-3001 Leuven, Belgium, silvia.armini@imec.be
The rate at which material is removed during Chemical Mechanical Planarization (CMP) and the
degree of defectivity induced by this process are determined by the size, shape, concentration
and hardness of the abrasives used in the polishing slurry. The tunable properties of polymer
nanospheres, in particular size and hardness modulation, through synthesis design, make them
particularly promising as cores in composite organic core/inorganic shell structures for
application in CMP. In this work, monodisperse PMMA-based terpolymer particles were
synthesized by suspension polymerization. Significant reaction parameters were varied in an
effort to prepare particles with a wide and controllable range of size and polymer content. With
the aim of understanding the effects of the amount of main monomer, MMA, we found that the
average particle size increased within the range 250 to 550 nm with increasing amount in the
feed as expected. The particle size distributions obtained were narrow, with a variation of  14
nm. The reaction temperature, varied in the range 60-80 C, showed a significant impact on the
polymerization rate and the final particle size and shape. Finally, the influence of the
concentration of the initiator, 2,2’-Azobis(2-methylpropionamidine) dihydrochloride, is
surprisingly less pronounced and the trend in the particle size behavior is ill-defined.
14-29
Synthesis and characterization of spirobenzopyran based photoactive polymeric coatings
grafted onto flat surfaces and colloidal particles
MARTIN PIECH, Nelson S. Bell, Sandia National Laboratories, Chemical Synthesis and
Nanomaterials Department, NM, mpiech@sandia.gov
To prepare robust photoactive coatings, the grafting of spirobenzopyran methyl methacrylate-comethyl methacrylate copolymers from flat silica surfaces and colloidal particles has been
performed applying the atom trasfer radical polymerization (ATRP) method. The reaction
conditions were optimized with respect to the kind and concentration of surface bound initiator,
the type of halide and ligand used in the catalytic complex, presence/absence of untethered
initiator and inhibitor, solvent, and temperature. This approach facilitated controlled synthesis of
very uniform coatings up to 80  3 nm thick. The content of spirobenzopyran chromophore in
the polymer matrix was systematically varied to produce the surfaces and particles with varying
characteristics. Exposure of these coatings to alternating UV and visible light irradiation
produced reversible wettability changes on surfaces and control of colloidal dispersion stability
in particulate suspensions. In this talk, the synthesis and characterization of these photoactive
materials will be described in detail with a brief summary of photophysical effects.
15-01
Non Classical Crystallization
HELMUT CÖLFEN, Max-Planck-Institute of Colloids and Interfaces, Colloid Chemistry, Am
Mühlenberg, D-14424 Potsdam, Germany, Coelfen@mpikg.mpg.de
In recent years, increasing evidence is reported that many crystallization events do not obey the
laws of classical crystallization i.e. an ion or molecule attachment to a critical crystal nucleus.
Starting from the consideration of biominerals with their often complex forms and several levels
of hierarchy, a view of particle mediated crystallization events is developed, often starting with
amorphous precursor nanoparticles. These precursor particles undergo mesoscopic
transformation to nanocrystals and assembly processes to superstructures with complex shape.
Some of such intermediates called mesocrystals are shown, which could explain the inclusion of
macromolecules in single crystalline biominerals. Subsequent crystallographic fusion of
mesocrystals can lead to single crystals with preserved shape. Direct nanoparticle fusion
according to the mechanism of oriented attachment can directly lead to single crystals, which
will be demonstrated. Also, Polymer Induced Liquid Precursors (PILP's) will be shown as
precursor species in non-classical crystallization events leading to complex morphologies for the
case of amino acid crystals.
15-02
Principles of Biominerals Architecture: Nucleation Mediated Self-Assembly Of Biomineral
Crystals
XIANG Y. LIU, Department of Physics, Faculty of Sci., National University of Singapore, 2
Science Drive 3, Singapore, phyliuxy@nus.edu.sg
Bones and teeth are biocomposites which are self assembled in a certain manner that require
controlled mineral deposition during their self-assembly to form tissues with unique mechanical
properties. Various biomolecules play a pivotal role during the formation biomineral nano
crystallite assembly. However, the mechanisms of biomolecule-mediated mineral initiation are
far from understood. In this contribution, I will present that the formation of the well-aligned
hydroxyapatite nano crystallite assembly is controlled by the so-called self (homo)-epitaxial
nucleation mediated assembly (SENMA) mechanism, which unfortunately will be demolished at
high supersaturations due to the unflavored kinetics (supersaturation driven structural mismatch).
It is identified for the first time that biomolecules, e.g. chondroitin sulfate, facilitate the
formation of a well-aligned HAP assembly by suppressing the supersaturation driven structural
mismatch rather than by “cementing” HAP crystallites.
15-03
Noncovalent Functionalization of Carbon Nanotubes Using Designed Peptides
G. R. DIECKMANN, Department of Chemistry and NanoTech Institute, The University of
Texas at Dallas, Richardson, TX , dieckgr@utdallas.edu
To fully realize the potential utility of carbon nanotubes, strategies for the effective
solubilization, separation and organization of these materials must be devised. In this
presentation the use of designed amphiphilic peptides to achieve these goals will be described,
with a focus placed on the peptide design, as well as the characterization of the resulting
peptide/nanotube composites. Results from circular dichroism, Raman, UV/Vis/NIR, SEM and
TEM studies will be discussed which demonstrate that designed amphiphilic peptides are
effective at solubilizing carbon nanotubes in aqueous solution, debundling the nanotubes
yielding long individual nanotubes, and organizing them into different macromolecular
architectures depending on solution conditions. The ability to control nanotube organization by
utilizing the self-assembly properties of the peptides provides a facile and versatile method for
the manipulation of carbon nanotubes for future applications.
15-04
Manufacturing with Micro-organisms: Merging Biological Self-Assembly with Synthetic
Chemistry to Yield Functional 3-D Nanoparticle Structures
KENNETH H. SANDHAGE1,2, Shawn M. Allan1, Samuel Shian1, Michael R. Weatherspoon1,
Christopher S. Gaddis1, Phillip D. Graham1, Ye Cai1, Michael Haluska1, Gul Ahmad1, Benjamin
Church1, Robert L. Snyder1, Dori Landry3, Mark Hildebrand3, Brian P. Palenik3 1School of
Materials Science & Engineering, Georgia Institute of Technology, Atlanta, GA, 2Institute for
Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 3Marine Biology
Research Division, University of California at San Diego, San Diego, CA,
ken.sandhage@mse.gatech.edu
Appreciable global effort is underway to develop new routes to three-dimensional (3-D)
nanostructured devices. To enable widespread commercialization, such processes must be
capable of: i) precise 3-D fabrication on a fine scale and ii) mass production on a large scale.
These often-conflicting requirements can be addressed with a revolutionary new paradigm that
merges biological self-assembly with synthetic chemistry: Bioclastic and Shape-preserving
Inorganic Conversion (BaSIC). Nature provides spectacular examples of micro-organisms
(diatoms, coccolithophorids, etc.) that assemble intricate bioclastic 3-D structures. For example,
tens of thousands of diatom species currently exist, with each species assembling silica
nanoparticles into a microshell with a distinct 3-D shape and pattern of fine features. Through
sustained biological reproduction, diatoms can generate enormous numbers of 3-D
micro/nanostructures with identical morphologies. Such massive parallelism and speciesspecific (genetically-controlled) precision are highly attractive for device manufacturing.
However, natural bioclastic chemistries are rather limited. With BaSIC, synthetic approaches
have been developed to convert biogenic assemblies into non-natural chemistries (e.g., TiO2,
ZrO2, MgO, BaTiO3, polymers, etc.), while preserving the 3-D shapes and fine (nanoscale)
features. Future research on the genetic engineering of biomineralizing micro-organisms may be
coupled with BaSIC to yield low-cost nanostructured devices with tailored shapes and tailored
chemistries.
15-05
Preparation of Small Materials by Interface Selective Reactions Using Biological Materials
as Templates
Y. B. KIM, Department of Nano-Polymeric Systems, PaiChai University, Daejon, South Korea,
ybkim@mail.pcu.ac.kr
Hydrolysis and condensation reactions of water soluble precursors of titania, alumina, silica,
silsesquioxane and iron oxide were examined in the presence of interfaces of oil and water or gas
and water. Hydrolyzed products from some of these precursors showed interface selectivity as
inorganic materials formed selectively at the interfaces. Oil drops and air bubbles coated with
silica, titania, alumina, or iron oxide were successfully prepared at room temperature. This type
of reaction was applied to coat biological templates that had regular structures such as lipid
tubes, hairs, gills of mushrooms, fungi, fibroblasts, and bacteria. The biological materials coated
with silica, alumina and titania formed smaller and more rigid replicas of their original shapes
than uncoated ones. The sizes of replicas were usually 1/10 to 1/20 of the original materials.
Results indicated that most biological materials would be useful as templates to prepare regularly
shaped smaller structures made of different inorganic materials.
15-06
Morphosynthesis of Complex Inorganic Forms Using Pollen Grain Templates
SIMON R. HALL*, Helen Bolger, Vicky Swinerd, Stephen Mann, School of Chemistry,
University of Bristol, Bristol, United Kingdom, s.hall@bristol.ac.uk
Biological structures are distinguished by the extremely high precision of their self-assembly,
replication and functionality, and as such provide novel platforms and templates on which to
construct and organize chemical processes.
In this work, we describe an exceedingly facile method for replicating the complex surface
morphology of flower and tree pollen grains, which in the case of silica produces complex
colloidal materials with surface areas higher than 800m2/g. Pollen is a ubiquitous and
inexpensive material with a high degree of species-specific morphological complexity. The
tough outer shell (exine) of pollen grains is amenable to inorganic mineralization without
consequent loss of fine structure, either as a result of geological processes, or as described here
through synthetic methods. We show that high-fidelity hollow inorganic replicas of pollen grains
can be achieved with both amorphous (silica) or crystalline (calcium carbonate, calcium
phosphate) minerals, and demonstrate their potential applicability by post-synthetic
functionalization with magnetic or metallic nanoparticles. As proof-of-concept, we also show
that the biocompatible replicas can be loaded with the anti-inflammatory drug, ibuprofen, the
anti-histamine, chlorpheniramine, and used as a potential drug delivery system with controlled
release properties.
15-07
From Organic Supramolecular Architectures to Inorganic Nanotubes
J. H. JUNG, Nano Material Team, Korea Basic Science Institute (KBSI), 52 Yeoeun-dong,
Yusung-ku, Daejeon, 305-333, S. Korea, jonghwa@kbsi.re.kr
A diversity of supramolecular structures can be created, not only in nature but also in artificial
systems, by self-assembly of designed “organic” building blocks. In contrast, creation of such
diverse supramolecular structures from “inorganic” materials seems to be very difficult or
nearly impossible. We have studied self-assembled superstructures of crown-appended
cholesterol, cyclohexane-based, and sugar-integrated gelators in organic solvents and water.
They acted as versatile gelators of organic fluids such as alcoholic and polar solvents. Crownappended cholesterol gels showed lamellar, multi-layered vesicular, helical and nano-tubular
structures. On the other hand, the sugar-based gels displayed the nano-sized bundle fiber and the
double-helical fiber structures. To transcribe of these superstructures into the silica or titania,
sol-gel polymerization of tetraethoxysilane (TEOS) was carried out using organogels as
templates to obtain novel structure of the silica in the absence or the presence of metal ions.
After calcination, crown-appended cholesterol gelators were induced single, multi-layered
nano-tubular, multi-layered vesicular and the helical ribbon structures of the silica. In addition,
sugar-integrated gels were created lotus-type, spherical and the double-helical nano-tubular
structures of the silica. Here, I shall discuss on the self-assembled superstructures of
organogelators and the transcription of these assembled structures into inorganic nanotubes.
15-08
GEPI: Genetically Engineered Polypeptides for Inorganics as Molecular Erectors in Nanoand Nanobio-technology
C. Tamerler,1 D. T. Schwartz,2 R. Samudrala,3 F. Baneyx,2, MEHMET SARIKAYA,1,2,
1
Materials Science and Engineering, 3Microbiology, and 2Chemical Engineering, University of
Washington, Seattle, WA, sarikaya@u.washington.edu
Physical and chemical functions of single celled and multi-cellular organisms are carried out
through recognition and sensing by a very large number (billions) of proteins through predictable
and self-sustaining molecular interactions. These functions include ion or charge exchange or
transport, chemical recognition and control via enzymatic reactions, material synthesis,
nucleation, growth and formation. Using biology as a guide, we design, synthesize, genetically
tailor and utilize short polypeptides for potential molecular erectors, linkers, bracers, and spacers,
or simply as molecular sensors, in recognition, self-assembly, ordered organization, and
fabrication of nanoinorganic materials and molecularly hybrid systems in nanotechnology
(molecular electronics and photonics) and nanobiotechnology (bio-sensors, -assays, and materials). Based on the fundamental principles of molecular biomimetics, i.e., molecular
recognition, self-assembly, and genetic-based fabrication, and adapting combinatorial biology
protocols, we can now genetically engineer polypeptides to specifically recognize inorganic
surfaces and synthetic functional molecules. Once combinatorially selected and their binding
experimentally characterized, combining the bioinformatics and biophysical approaches, these
GEPIs can be post-selection genetic engineered to further tailor their functions to create
molecular functional constructs, versatile fundamental molecular recognition elements. This
presentation will review the latest developments in this rapidly developing polydisciplinary field
and demonstrate practical utilizations.
15-09
Biomimicking Drug Transport Systems
A. J. KHOPADE, Sun Pharma Advanced Research Centre, Tandalja, Vadodara-390 020,
Gujarat, India, ajkhopade@sunpharma.com
The indigenous nutrient transport systems (Biovectors) of the body such as, circulating
lipoproteins, red blood cells and protein coacervates are inspiring for the synthesis of
nanomaterials for delivering bioactives because of the unique surface characteristics that render
them a very high biological half-life. Some of the bioinspired drug delivery systems are
described as follows: Lipoprotein mimicking biovectors (LMBVs) are nanoemulsions or solid
lipid nanoparticles made up of lipoprotein components or their synthetic counterparts. LMBVs
are useful in delivering/targeting lipid soluble drugs. Supramolecular biovectors (SMBVs) are
synthetic analogues of lipoproteins designed to deliver hydrophilic drugs. SMBVs consist of a
hydrophilic nanoparticle core (for drug loading), surface-grafted with lipid and surrounded by a
phospholipid monolayer. Ultrathin microcapsules prepared using layer-by-layer technique are
cell-mimicking biovectors (CMBVs), which display the typical characteristics of the cell
membranes such as nanometer thickness and elasticity. Different types such as pseudo-vesicles
and ultrathin capsule-liposome hybrid are possible variations of CMBVs. Globular proteins are
water rich structures that can be used for delivery of protein binding drugs. Globular protein
mimicking biovectors (GMBVs) are nano coacervates or nanogels that are water-rich, waterinsoluble bodies due to lot of water associated with them. Biomineralized spherical inorganic
nano-calcium phosphate covered with water-associated sugars, called aquasomes, are used for
protein delivery. The experimental experience regarding their synthesis and pharmaceutical use
shall be discussed in the presentation.
15-10
Biomimetic Polymer Networks as Functional Components in Diagnostic and Therapeutic
Microdevices
J. ZACH HILT, Department of Chemical and Materials Engineering, University of Kentucky,
Lexington, KY, hilt@engr.uky.edu
Biomimetic polymer networks with tailored affinities and transport properties for a target
molecule have been developed, and these networks have been demonstrated as functional
components in micro- and nanoscale diagnostic and therapeutic devices. For controlled drug
delivery, these polymers can enhance control over the transport properties of therapeutic
molecule and the corresponding release profile. In biosensors, these polymers are advantageous
alternatives since they do not incorporate any biological components but mimic biological
recognition pathways, while being more robust and cost effective. Specifically, glucose
responsive copolymer networks containing poly(ethylene glycol) n dimethacrylate (where n is
the number of EG repeat units) at various crosslinking percentages and acrylamide as a
functional monomer were synthesized in polar, aprotic solvent (dimethyl sulfoxide). Of
particular interest, methods were developed to micropattern these polymer networks with
controlled thicknesses. The equilibrium binding characteristics and the kinetic binding and
release characteristics of a fluorescent glucose analogue was analyzed using fluorescent
microscopy techniques. Methods were developed to integrate these networks with substrates at
the micro-/nanoscale, enabling the fabrication of microdevice platforms that are based on silicon
technologies.
15-11
Polymorphism of DNA-Anionic Liposome Complexes Reveals Hierarchy of Ion-Mediated
Interactions
GERARD C. L. WONG* *Department of Materials Science & Engineering, Department of
Physics, Department of Bioengineering, University of Illinois at Urbana-Champaign, IL,
†Laboratory of Physical and Structural Biology, National Institute of Child Health and Human
Development, NIH, Bethesda, MD, gclwong@uiuc.edu
Self-assembled DNA delivery systems based on anionic lipids complexed with DNA using
divalent cations have been recently introduced as an alternative to cationic lipid-DNA complexes
due to their low cytotoxicity. We investigate anionic lipid-DNA (AL-DNA) complexes induced
by different cations using synchrotron Small Angle X-ray Scattering (SAXS) and confocal
microscopy to show how different ion-mediated interactions are expressed in the self-assembled
structures and phase behavior of AL-DNA complexes. Divalent ions can mediate not just DNAmembrane attractions, but also inter-membrane and inter-DNA attractions, both absent in
cationic lipid-DNA complexes. Moreover, divalent cations can coordinate non-electrostatically
with lipids and modify the resultant membrane structure. We find that at low membrane charge
densities, AL-DNA complexes organize into a lamellar structure of alternating DNA and
membrane layers crosslinked by ions. At high membrane charge densities, a new phase with no
analog in cationic lipid-DNA systems is observed: DNA is expelled from the complex, and a
lamellar stack of membranes and intercalated ions is formed. For a subset of the ionic species,
high ion concentrations generate an inverted hexagonal phase comprised of DNA strands
wrapped by ion-coated lipid tubes. A simple theoretical model shows that this transition is
consistent with an ion-induced change in the membrane spontaneous curvature.
15-12
Directed Cell Migration via Chemoattractants Released from Degradable Microspheres
XIAOJUN ZHAOa,b,1, Siddhartha Jainb1, H. Benjamin Larmana, Sandra Gonzaleza, Darrell John
Irvineab, aDepartment of Materials Science & Engineering, Massachusetts Institute of
Technology, Cambridge, MA, bBiological Engineering Division, Massachusetts Institute of
Technology, Cambridge, MA, djirvine@mit.edu
Chemotaxis, cell migration directed by spatial concentration gradients of chemoattractant
molecules, is critical for proper function of the immune system. Materials capable of generating
defined chemoattractant gradients via controlled release may be useful for the design of
improved vaccines and immunotherapies that draw specific cells to an immunization site. To this
end, we encapsulated formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fN’LFN’YK) peptides or macrophage
inflammatory protein-3a (MIP-3a or CCL20) in degradable poly (lactide-co-glycolide)
microspheres that provided sustained release for more than 2 weeks in vitro.
fN’LFN’YK and MIP-3a chemoattract dendritic cells (DCs), the key antigen-presenting cells
involved in generation of primarimmune responses, and their precursors, monocytes. Using an in
vitro videomicroscopy migration assay, we detected strong chemotaxis of human monocytes and
monocyte-derived DCs through 3D collagen gels toward microspheres releasing fN’LFN’YK.
Similarly, microparticles releasing MIP-3a were able to attract mouse bone marrow-derived
dendritic cells. Strikingly, prolonged attraction of DCs from distances up to 500 mm from the
source to the point of contact with individual microspheres was observed. Such microspheres
could be of general interest for the design of vaccines that promote adaptive immunity and as a
platform for studying the biology of chemotaxis in vitro and in vivo.
15-13
Biomimetic Processing through a Polymer-Induced Liquid-Precursor (PILP) Process
Matthew J. Olszta, Yi-Yeoun Kim, Xingguo Cheng, Lijun Dai, LAURIE B. GOWER,
Department of Materials Science & Engineering, University of Florida, Gainesville, FL,
lgowe@mse.ufl.edu
Studies by the biomineralization community are finding that some of the classic examples of
biominerals are formed by an amorphous precursor phase. It seems reasonable to assume that
this is one of the primary functions of the acidic proteins associated with biominerals because
this can provide a relatively simple means of “molding” elaborate crystal morphologies, the
hallmark of biominerals. However, Meldrum and coworkers have demonstrated that elaborate
single-crystalline morphologies can also be molded simply by proper selection of the “mold” and
crystallization conditions. If this is the case, then one must wonder why Mother Nature has
apparently chosen to use the amorphous precursor route? This talk will attempt to address this
question through examples taken from our in vitro model system, which demonstrates that the
fluidity of the amorphous phase may be critical for achieving some of the morphological features
found in biominerals, such as mineral fiber formation via a solution-precursor-solid (SPS)
mechanism, templating single crystals via deposition of colloidal droplets, and intrafibrillar
mineralization of collagen. Therefore, our focus is not only on determining how the polymer
stabilizes the amorphous phase, but also on how it entraps sufficient hydration waters to impart
the amorphous precursor with fluidic character.
15-14
Aragonite Growth on Carbonate-Free Single Crystal Substrates
BOAZ POKROY, Emil Zolotoyabko, Department of Materials Engineering, Technion – Israel
Institute of Technology, Haifa, Israel, bpokroy@tx.technion.ac.il
Although biogenic crystals are grown under standard pressure and temperature, they often exist
as metastable polymorphs. A good example is aragonite formation in seashells. Among different
factors influencing the biomineralization process, much work had been done in understanding
the function of impurity atoms and macromolecules. Special attention has been given to the role
of lattice mismatch and stereochemistry. In this research, we tried to determine the net mismatch
effect on aragonite growth, eliminating as far as possible the stereochemical contribution. For
this purpose, we used several commercially available wafers free of carbonate groups, namely
rhombohedral sapphire and lithium niobate, trigonal quartz and cubic silicon. All wafers were
cut perpendicular to the threefold axis in order to obtain a trigonal symmetry of cations in the
surface plane, which is similar to the local symmetry of Ca ions in the (001) plane of calcite and
aragonite.
Experimental results [1] clearly show that aragonite can nucleate and grow c-oriented at
mismatches up to 11%. It appears, that up to this value, the reduction of interfacial energy
allowing aragonite formation prevails over the increase in the mismatch-induced strain energy.
Note that we did not completely suppress the formation of calcite, but facilitated the concurrent
nucleation of aragonite crystals. These findings could shed an additional light on the metastable
polymorph growth in biogenic crystals.
15-15
Morphological Control of Inorganic Crystals
F. C. MELDRUM, N. Hetherington, A. N. Kulak, E.Loste, R.J. Park, W. Yue, School of
Chemistry, University of Bristol, Bristol, United Kingdom, Fiona.Meldrum@bristol.ac.uk
One of the most immediately striking features of many biominerals is their remarkable
morphologies. While many biominerals exhibiting unusual shapes and curved surfaces are
amorphous in structure and therefore without a preferred morphology, many biogenic single
crystals also exhibit overall morphologies which do not reflect the internal crystal structure, such
as the sponge-like calcite skeletal plates of echinoderms. The research described here adopts a
biomimetic approach to investigate morphological control of inorganic single crystals. Calcium
carbonate has been precipitated within the confines of the regular cylindrical pores of track etch
membranes, and the role of an amorphous calcium carbonate (ACC) precursor in morphological
control of the product crystals was investigated. A more dramatic demonstration of the control
of single crystal morphology was obtained on precipitation of a range of crystals in polymer
membranes with sponge-like morphologies. Under a specific range of reagent concentrations,
single crystals with sponge-like morphologies were precipitated, as dictated by the confines of
the polymer membrane. These experiments demonstrate that simple shape-constraint is
sufficient to produce single crystals with non-crystallographic morphologies. Patterning of the
surfaces of single crystals has also been produced by precipitation of inorganic crystals on arrays
of close-packed silica or polystyrene spheres.
15-16
Preparation, Characterization and Properties of Nanocrystalline Apatites: Significance for
Bone Mineral and Biomaterials
D. Eichert, S. Cazalbou, C. COMBES, H. Sfihi*, C. Drouet, C. Rey, CIRIMAT, UMR CNRS
5085, Equipe Physico-Chimie des Phosphates, ENSIACET, 118 route de Narbonne, 31077
Toulouse cedex 4, France, *Laboratoire de Physique Quantique, ESPCI, 10 rue Vauquelin,
75231 Paris, France, Christele.Combes@ensiacet.fr
Biological poorly crystalline apatites are the main constituent of mineralized tissues (bone and
dentine) but despite their widespread occurrence, the structure, properties and mode of formation
of the apatite nanocrystals are still the subject of discussion. Synthetic nanocrystalline apatites
can be easily prepared in aqueous media under ambient conditions. One of the most interesting
characteristics of the nanocrystals, revealed by spectroscopic methods (FTIR, NMR), is the
existence of a hydrated surface layer, exhibiting a very fragile structure irreversibly altered on
drying, that is well developed in freshly formed precipitates. This surface layer contains labile
ionic species which can be easily and rapidly exchanged with ions from the surrounding fluids.
The ion mobility in the hydrated layer can be related to processes of regulation of the mineral ion
concentration in body fluids and also to “crystal fusion”, often observed in bone and tooth
enamel, by allowing direct crystal-crystal bonding. This process could occur in self-setting
biomimetic calcium phosphate cements. Although the precise structure of the hydrated surface
layer is not yet precisely known, we can take advantage of apatite nanocrystal surface reactivity
to prepare biomaterials (ceramics, coatings, composites) at low temperature with preserved and
adaptable bioactivity.
15-17
From Amorphous Calcium Phosphate to Artificial Implants
H. FÜREDI-MILHOFER, Casali Institute of Applied Chemistry, the Hebrew University of
Jerusalem, Jerusalem, Israel, Helga@vms.huji.ac.il
Osteointegration of artificial implants for bone and tooth replacement or repair is facilitated by
coating the surfaces of bioinert materials (metals, polymers) with calcium phosphates. In recent
years there is growing interest in biologically inspired methods in which calcium phosphate
deposition is initiated at room or physiological temperature from low concentration aqueous
solutions containing inorganic ions present in human blood plasma (simulated body fluid, SBF).
In order to facilitate crystal growth from these solutions, the implant surface is being modified by
introducing functional groups or by first depositing amorphous calcium phosphate, ACP, which
then serves as a template for subsequent crystal growth. Another important issue is the inclusion
of bioactive macromolecules (drugs, growth hormones, etc.) into the coatings, which has so far
been attempted by coprecipitation with the inorganic phase. However macromolecules, if present
in a crystallizing solution, profoundly influence the crystallization kinetics and properties of the
nascent of inorganic salts. Consequently, although coprecipitation of macromolecules is possible,
the properties of the calcium phosphate coatings may be profoundly affected in the process.
Apparently understanding the fundamental problems associated with nucleation and growth of
calcium phosphate crystals in the presence of macromolecules is of high relevance.
In the first part of this paper we shall address this problem in a review of our recent findings on
the influence of polyelectrolytes, PEs, on nucleation and growth of calcium phosphate crystals,
with specific attention to ACP – crystalline phase transformation and to the properties of the
nascent precipitates. It will be shown that most PEs exhibit a dual effect, i.e. any particular
macromolecule may inhibit or induce crystallization, the type and intensity of the effect
depending on the type, charge and solution concentration of the macromolecule.
In the second part of the lecture a new, generalized method for the production of coatings of
bioinert implant materials will be described, which allows one to avoid the problem of
coprecipitation altogether. The method is based on initial deposition of an organic matrix in the
form of a polyelectrolyte multilayer, PE ML, and subsequent deposition of ACP particles from
an aqueous suspension. The procedure is repeated several times until an organic – inorganic
multilayer coating of required thickness is obtained, which is then immersed into a metastable
calcifying solution to initiate “in situ” crystal growth within the organic matrix. Novel organicinorganic nanocomposite coatings, consisting of positively or negatively charged PLL – PGA
multilayers (where PLL is poly-L-lysine, PGA is poly-L-glutamic acid), and calcium phosphate
deposited in the amorphous form, or crystallized “in situ” upon and/or within the multilayers
have been prepared and characterized. Adhesion and proliferation of human osteoblast cells on
selected coatings has also been determined. Mechanical and biological tests have shown that
composite coatings containing “in situ” grown poorly crystalline apatite and final PLL-PGAlayers possess appropriate biomechanical stability with well adapted adhesion sites for cell
adhesion, sufficient cell growth and cell differentiation.
The advantages of the described coatings for bioinert implant materials are obvious. The coating
procedure is relatively simple and can be automatized. Both the organic matrix and the mineral
phase are prepared "in situ" and the growth kinetics and properties of the inorganic phase can be
controlled by strict control of the experimental conditions. The coating process is not sensitive to
the nature, size and topology of the substrate. Bioactive proteins (drugs, growth hormones, etc.)
can be incorporated within the organic matrix without loosing their bioactivity. Since the organic
matrix is laid down independently of the deposition of the inorganic material, the influence of the
added macromolecules on the properties of the inorganic phase can be minimized.
15-18
Exploiting Oriented Aggregation to Control Nanocrystal Size and Shape
R. LEE PENN, Anthony Ratkovich, David J. Burleson, Department of Chemistry, University of
Minnesota, 207 Pleasant St., Minneapolis, MN, penn@chem.umn.edu
Oriented aggregation of nanocrystals is an important mechanism of particle growth in the
solution-phase synthesis of oxide nanoparticles. Oriented aggregation is a special case of
aggregation in which primary nanocrystals are aligned with respect to one another, resulting in
the formation of new single crystals, often with unique morphologies. Nanocrystal growth by
oriented aggregation is highly dependent on solution chemistry and may provide a means by
which intricate nanostructured objects can be produced. Furthermore, surfactants can
dramatically change the rate of oriented aggregation. Results from zinc oxide and iron oxide
experiments will be presented.
15-19
Unusual Particle Shapes and Assembly Structures from Mineralized Hydrolgel
Microspheres – a Bioinspired Route to Hierarchical Structural Complexity
DAYANG WANG, Min Kuang, Gang Zhang, Helmuth Möhwald, Max Planck Institute of
Colloids and Interfaces, D-14424, Potsdam, Germany, dayang.wang@mpikg-golm.mpg.de
Hydrogel microspheres are spherical hydrophilic polymer networks, swelling or shrinking in
response to environmental variables such as pH and temperature. Thanks to their excellent
biocompatibility, aqueous inner interior environment, and facility of conjugation with biomacromolecules, hydrogel microspheres provide appealing analogues of biological organism,
such as single cell compartments. This presentation will be focused on mineralization of CaCO3
within hydrogel microspheres, creating inorganic/organic composite particles with unusual
shapes. Various nanoparticles were incorporated into the hydrogel spheres based on their
stimulus-sensitive swelling behavior. The introduction of nanoparticles enables not only adding
diverse functions into the composite particles obtained but controlling their shapes also. After
dip-coating on substrates, intriguingly, CaCO3-loaded hydrogel microspheres are organized in a
two-dimensional (2D) hexagonal non-close packing array, rather different from conventional 2D
colloidal crystals. The separation distance of the neighboring particles can be tuned in a
controlled fashion. Reminiscent to the corneas structure of moth eyes, the resulting 2D non-close
packing structures render the substrates anti-reflective, suppressing the reflection of light. Owing
to their similarity to lithographic patterns, they were further recruited as templates for selfassembly of other particles. The resulting binary structures can be easily manipulated by the
surface wettability.
15-20
Dendrimers and Diatoms: Bio-Inspired Routes to Functional Metal Oxides.
S.L. Sewell, K.C. Halfpenny, D.W. WRIGHT, Department of Chemistry Vanderbilt University,
Nashville, TN, david.wright@vanderbilt.edu
Unicellular plankton known as diatoms are able to produce ornate nanostructures of silica at
ambient conditions. In contrast, current materials approaches require extremes of temperature
and pH. Diatoms are able to biomineralize the silica using species specific peptides known as
silaffins that possess lysine residues heavily post-translationally modified with polyamines.
Herein, we report the use of amine-terminated dendrimers as mimetic templates for silica
condensation. Further, the unique host-guest capabilities of the dendrimer may be used to create
novel functional silica nanospheres with applications in supported heterogeneous catalysis,
biocatalysts, and as biological probes.
15-21
Bioinspired Nanomaterials Synthesis
MURALI SASTRY,Absar Ahmad, Nanoscience Group, Materials Chemistry Division, National
Chemical Laboratory, Pune – 411 008, India, sastry@ems.ncl.res.in
The study of the synthesis, exotic properties, assembly/packaging and potential commercial
application of nanomaterials is an extremely important topic of research that is expected to have
far-reaching impact global impact. The focus of my talk will be on an emerging branch of
nanotechnology that derives its inspiration from biology. Recognizing that some of the most
exquisite and highly functional nanomaterials are grown by biological systems (examples
include silica by diatoms and magnetic nanoparticles by magnetotactic bacteria), many
researchers have focused attention on understanding how inorganic materials are made by
biological systems and attempting to replicate such processes in the lab. In my laboratory, we
have investigated the use of plant organisms such as fungi in the synthesis of nanomaterials over
a range of chemical compositions that include metals, metal sulfides and oxides. An exciting
recent development is the use of plant extracts in nanoparticle synthesis wherein large
concentrations of gold nanotriangles have been obtained that have potential application in cancer
hyperthermia. Organisms such as fungi are not normally exposed to metal precursor stresses –
that they should be capable of a broad range of biochemical transformations to negate these
stresses is useful in materials chemistry and throws up exciting possibilities.
15-22
Bionanotechnology Approach in Material Synthesis and Device Fabrication by Applying
Peptide/Protein Assemblies
HIROSHI MATSUI, Department of Chemistry, City University of New York, the Graduate
Center and Hunter College, New York, NY, hmatsui@hunter.cuny.edu
Non-lithographic fabrications of devices such as electronics and sensor have been studied
extensively by assembling nanometer-sized building blocks into the device configurations. While
various nanocomponents have been applied as building blocks to construct nanodevices, the
more reproducible methods to assemble them onto precise positions are desirable. We have been
fabricating peptide-based nanotubes (antibody) and functionalizing them with various
recognition components (antigen), and our strategy is to use those functionalized peptide
nanotubes, which can recognize and selectively bind a well-defined region on patterned
substrates, as building blocks to assemble three-dimensional nanoscale architectures at uniquely
defined positions and then decorate the nanotubes with various materials such as metals and
quantum dots for electronics and sensor applications. This coating was obtained by incorporating
certain peptide sequences into peptide nanotubes that can selectively grow specific nanocrystals
on nanotubes via biomineralization. By controlling the peptide conformation on the nanotubes,
the nanocrystal size, packing density, and shape were controlled. This sequence peptideincorporated nanotube is expected to become a conductivity-tunable building block for
nanodevices.
In Nature, proteins and peptides mineralize various types of metal/semiconductor nanocrystals at
room temperature in ambient pressure, which are difficult to achieve in synthetic manner. For
future material syntheses, the production of monodisperse nanocrystals at an ambient condition
is an important technology to develop. We mimic natural biomineralization systems, and we are
succeeded to grow unusual nanocrystals at room temperature in ambient pressure in doughnutshaped peptide assemblies. The peptide nano-doughnuts were self-assembled from peptides and
organic salts. Nanocrystals grown inside the peptide nano-doughnuts were extracted by
destroying the doughnut templates via long UV irradiation. The size of nano-doughnut can be
control by pH, and therefore the size of nanocrystals can also be controlled. These nanodoughnuts can be self-assembled on specific locations of substrates patterned by AFM-based
nano-lithography. Since the size and the interval between nanocrystals are controllable, these
nano-doughnut assemblies can be applied to photonics and optics.
15-23
Self-Assembled Nanofibers and Tubes from Biobased Synthetic Amphiphiles
GEORGE JOHN, Department of Chemistry, City College of the City University of New York,
Convent Avenue at 138th Street, NY, john@sci.ccny.cuny.edu
The self-assembly of low molecular weight building blocks into nanoscale molecular objects has
recently attracted considerable interest in terms of the bottom-up fabrication of nanomaterials
The building blocks currently used in supramolecular chemistry are synthesized mainly from
petroleum-based starting materials. However, biobased organic synthesis presents distinct
advantages for the generation of new building blocks since they are obtainable from renewable
resources. This study is an effort to combine the philosophies of green chemistry and
supramolecular chemistry, making use of renewable plant-derived resources as the starting
materials (an alternate feedstock) for the noncovalent synthesis of meso- and nanoscale
structures. The use of cardanol (obtained from Anacardium occidentale L, a renewable resource
and by-product of cashew industry) and its derivatives for various applications is well known.
However its use in the synthesis of aryl glycolipids and their self-assembled nanostructures are
new to the literature. The glycolipids are self-assembled to form a variety of well-defined
nanostructures including liquid crystalline phases, nanofibers, low-molecular weight gelators and
nanotubes under suitable conditions, which could be of use in material applications. Also address
the synthetic strategy for new amphiphiles and advances that have led to the understanding of
chiral behaviour and the subsequent ability to control the structure of glycolipid nanostructures
and the resulting impact of this on future material applications.
15-24
Thermally Responsive Silica-Living Polypeptide Composite Particles.
S. Turksen, P. S. RUSSO, B. Fong, J. Qiu, E. Soto-Cantu, Department of Chemistry and
Macromolecular Studies Group, Louisiana State University, Baton Rouge, LA, chruss@LSU.edu
Core-shell composite particles have been prepared, each consisting of a silica-coated cobalt
-carbobenzyloxy-Lbenzyl-L-glutamate), is attached covalently. Core particles were coated with a mixture of amino
and passivating moieties through silylation reactions. The amino groups initiated the
polymerization, with attachment, of N-carboxyanhydride monomers, resulting in a
homopolypeptide shell. Characterization by dynamic light scattering confirmed the helix-coil
transition of the polypeptide shell, reminiscent of the coat proteins of certain viruses, through
repeated heating and cooling cycles in an organic solvent. The living nature of the polypeptide
shell has also been confirmed. The particles have a size and uniformity that leads to formation of
colloidal crystals. Magnetometer measurements suggest the particles are superparamagnetic.
Supported by NSF.
15-25
Active Transport and Assembly Using Motor Proteins
B. C. BUNKER, G. D. Bachand, A. K. Boal, S. B. Rivera, R. P. Manginell, J. M. Bauer, A. M.
Bouchard, G. C. Osbourn, E. D. Spoerke, Sandia National Laboratories, Albuquerque, NM, H.
Hess, University of Washington, Seattle, WA, V. Vogel, Swiss Institute of Technology, ETH,
Zurich, Switzerland, bcbunke@sandia.gov
Energy-consuming proteins including the motor protein kinesin and the microtubule-forming
protein tubulin participate in a wide range of materials transport and assembly functions in living
systems. Using such “nano-robots”, organisms can create and reconfigure materials via active
processes that are not limited by the diffusion and energy constraints encountered in classical
self-assembly processes. We are exploring the extent to which these active proteins can be
exploited in artificial microfluidic systems to transport and assemble objects ranging in size from
molecules to micron-sized objects. Our ultimate goal is to mimic biological processes such as
the assembly of diatom skeletons and the reconfiguration of particulate arrays in the colorchanging system of the chameleon. This talk will summarize progress made to date towards
achieving this goal, including stabilization of proteins for use in artificial environments, guiding
of transport, cargo manipulations (particle loading and unloading), and the generation of artificial
microtubule organizing centers as scaffolds for particle manipulations.
15-26
Biomaterials from Nanocolloids: Applications for Neurons
NICHOLAS A. KOTOV, Departments of Chemical Engineering, Biomedical Engineering and
Materials Science, University of Michigan, Ann Arbor, MI, kotov@umich.edu
The presentation will review the recent advances in the use of nanocolloids to add new
functionalities to biomaterials. Layer-by-layer assembly (LBL) affords preparation of ordered
layered structures from virtually unlimited palette of nanocolloids. Various functionalities of
nanocolloids afford preparation of targeted composites for evaluation of different neuronal
functions. Four examples will be discussed. Multilayers from TiO2 nanoshells afford selective
determination of neurotransmitters due to ion-sieving effect.
Strong, flexible and
electroconductive implants can be made from SWNT LBL multilayers. Stringent testing of
biocompatibility of these composites was undertaken and it was demonstrated that they are
suitable for long-term contacts with tissues. Stimulations of neurons through these films was
demonstrated. Nanoparticles with silver nanocolloids can be used to suppress inflammation
processes due to infection – one of the most important problems with implantable devices.
Photoactive multilayer from semiconductor particles were used to NG108*15 neuron precursor
cells on them. It was found that light adsorbed in the nanoparticle layers results in the electrical
excitation of the neurons making this system a functional analog of retina. Assemblies of claypolymer systems demonstrated exceptional toughness similar to that observed in bones. Layered
nanocomposites represent an exceptionally versatile tool for production of biomaterials with
novel applications derived from unique properties of nanostructured matter.
15-27
Electronic Nanodevice Piggyback on Live Bacteria
RAVI F. SARAF, Vikas Berry, Department of Chemical Engineering, University of NebraskaLincoln, Lincoln, NE, rsaraf@unlnotes.unl.edu
Biological motifs ranging from single biomolecule (i.e. DNA, proteins) and biomolecular
monolayers (i.e., S-layer), to single-cell (bacteria, viruses, diatoms) and multi-cellular
microorganisms (i.e., yeast), are shown to be highly versatile scaffolds for high density, selfassembly of nanoparticles. Leveraging the multi-scale organization in microorganism to fabricate
hybrid structure with ‘physical’ nanoscale devices can open doors to fabricate highly functional
(integrated) micro-systems. The key to exploiting the hierarchical structure of the microorganism
to fabricate electronic micro-system remains in obtaining physiologically well-integrated
biophysical hybrid structure interconnected to power and signal ports. We will discuss a
fabrication method of using the membrane nanostructure of bacteria to form micron-scale
(monolayer) percolating network of Au nanoparticles self-connected to power/signal ports.
Using the humidity-induced actuation characteristics of the bacterium to modulate the (single)
electron tunneling characteristics of the nanoparticle monolayer we demonstrate, a reversible and
robust, humidity-sensing device. A critical aspect that attributes to a successful device is that the
bacteria are alive during the entire device fabrication process. In contrast to most impedance
based microelectronic humidity sensors, the sensitivity of this device is best at low humidity
(relative humidity <20%).
15-28
Spontaneous Assembly of Macroporous Titania
A. Collins, D.C. Martin, S. DAVIS, S. Mann, School of Chemistry, University of Bristol, Bristol
BS8 1TS, United Kingdom, s.a.davis@bristol.ac.uk
Titania is a multifunctional material with a wide variety of potential uses in diverse areas such as
photocatalysis and bioactivity. There is considerable interest in the template-directed synthesis of
porous titania as the increased surface area and chemical accessibility of such materials offers
distinct advantages. Typically, porogens with well defined size and architecture, such as
emulsion droplets and colloidal crystals have been used in combination with preformed
nanoparticles or in-situ precipitation reactions to prepare macroporous ceramics. In this work, we
demonstrate the spontaneous formation of ordered macroporous titania from base catalysed solgel reactions and describe the photocatalytic properties of these materials.
15-29
Biotechnology and Biomimetics Opens New Routes to the Fabrication of Silica and Metal
Oxide Semiconductors
DAVID J. KISAILUS1,2,3,Mark Najarian1,2,3, James C. Weaver1,2,3, Yosuke Amemiya2,3, Joon
Hwan Choi1, Wenjun Yang2,3, Jan L. Sumerel2,3, Youli Li1;Daniel E. Morse1,2,3,4, 1Materials
Research Laboratory, UC Santa Barbara, Santa Barbara, CA, 2 California NanoSystems Institute,
Santa Barbara, CA, 3Institute for Collaborative Biotechnologies, UC Santa Barbara, Santa
Barbara. CA, 4 Dept. of Molecular, Cellular, and Developmental Biology, Santa Barbara, CA,
dkisa@engineering.ucsb.edu
Working with silica needles produced by marine sponges, our laboratory discovered that the
proteins we named “silicateins” catalyze and structurally direct the hydrolysis and
polycondensation of silica, titania, gallia and zinc oxide from alkoxide precursors at neutral pH
and low temperature. The silicateins are true enzymes, closely related to a well-known family of
hydrolases. These are the first reported examples of enzyme-catalyzed, nanostructure-directed
synthesis of these materials – and the first such syntheses at low temperature and neutral pH.
Interaction with the template-like protein surface is capable of stabilizing polymorphs of these
materials that otherwise are not normally observed at low temperatures. A preferential alignment
of the resulting nanocrystallites of gallia to the protein was recognized, suggesting an epitaxiallike relationship.
Biomimickry is currently being used to catalyze and template the growth of various metal
oxides. We are incorporating analogs of the critical amino acid residues found in silicatein’s
catalytic active site, anchoring these functional groups (via self-assembled monolayers on gold)
adjacent to one another to facilitate catalytic activity by the same mechanism exhibited by the
enzyme. Results have shown that biomimetics of the active site in silicatein are capable of
producing silica and metal oxides from alkoxide precursors at neutral pH.
15-30
Surface Patterning of Silica Nanostructures Using Bio-Inspired Templates and Directed
Synthesis
M. J. DOKTYCZ, E. A. Coffman, J. D. Fowlkes, A. V. Melechko, D. P. Allison, M. L. Simpson,
Life Sciences Division and Condensed Matter Sciences Division, Oak Ridge National
Laboratory, Oak Ridge, TN, doktyczmj@ornl.gov
Natural systems excel in directing the synthesis of inorganic materials for various functional
purposes. One of the best-studied systems is silica synthesis. Various biological and synthetic
polymers have been shown to template and catalyze silica formation from silicic acid precursors.
We will describe the use of poly-L-lysine to promote the synthesis of silica in neutral, aqueous
solution and when immobilized onto a silicon support structure under similar conditions. Either
reagent jetting or conventional photolithography techniques can be used to pattern the templating
polymer. Highly interconnected laminate structures are created after exposure to dilute solutions
of silicic acid. Photolithographic patterning of (3-aminopropyl) trimethoxysilane, a reagent that
mimics the lysine functional group, led to similar silica coatings. The described surface
patterning techniques offer a route to integrate conventional silicon patterning technologies with
biologically based material synthesis. Such combined fabrication techniques enable controlled
assembly over multiple length scales and an approach to understanding interfacial silica
synthesis as occurs in natural systems.
15-31
Biomaterials with Hierarchically Defined Micro- and Nano-Scale Structure
JIAN TAN1 and W. Mark Saltzman1, 2, 1 School of Chemical and Biomolecular Engineering,
Cornell University, Ithaca, NY, 2 Department of Biomedical Engineering, Yale University, New
Haven, CT, Jt75@cornell.edu
Biomaterials are becoming increasingly important in biomedical practice, particularly as the
population ages. Materials that are organized on multiple length scales bear a closer resemblance
to biological matrices than those with single scale features and materials with multi-scale
organization should be more advantageous in biomedical applications. Many studies have shown
that both the micrometer- and nanometer-scale features of materials could significantly influence
cellular responses, however, synthesis of organized structures with both length scales for direct
biomedical applications has been lacking. Nature has presented us numerous clues on how to
produce complex, organized structures. Using a hierarchical approach that mimics natural
material formation processes, we developed a method to produce materials with controlled
physical structures at both the micrometer and nanometer scale. Our method is based upon a preorganized micropatterned template and conformal transformation of the architecture with nanostructured minerals, namely hydroxyapatite. The newly developed materials were biocompatible
with bone cells, induced a range of desirable cellular responses, and may therefore have direct
application in bone tissue engineering. In addition, the design principles employed in this study
can be extrapolated to other classes of biomedical materials, including polymers, metals,
ceramics or hybrid combinations.
POSTER SESSIONS
ADVANCED NANOSTRUCTURED MATERIALS: SMART COLLOIDS
NANOPARTICLES. RESPONSIVE SURFACES AND THIN FILMS
AND
P1-01
Polymeric Nanotubes and Nanorods Made from Poly(Styrene alt. Maleic Anhydride) and
Poly(pyrrole)
Cécile Malardier-Jugroot, M.A. Whitehead, THEO G.M. VAN DE VEN, Pulp and Paper
Research Centre and Department of Chemistry, McGill University, 3420 University Street,
Montreal, QC, Canada, theo.vandeven@mcgill.ca
We recently discovered that it is possible to make nanotubes from alternating copolymers by
self-association. An example is poly(styrene-alt-maleic anhydride) (SMA). These polymers
consist of hydrophobic styrene groups, alternating with hydrophilic anhydride groups, which
hydrolyze in water into two carboxylic groups, which depending on pH, can be both protonated
(at low pH), both dissociated (at high pH), or one can be protonated and one dissociated (at
neutral pH). At neutral pH an internal H-bond stiffens the molecule. At low and high pH, SMA is
flexible and the conformation depends on the chirality of the chain, preventing self-association,
whereas for neutral pH the conformation is linear, irregardless of chirality, allowing for a regular
association between the chains. This association at pH 7 has been confirmed by dynamic light
scattering, Cryo-TEM and SANS. Molecular modeling has shown that the most stable
association complex is a nanotube in which 8 SMA chains make up one twist of a helix. The
outer diameter of the tube is about 4 nm and the inner diameter 3 nm. The tubes can grow to a
length of several microns. The tubes can also associate with themselves, forming sheets, which
can stack upon each other. Cryo-TEM and SANS confirm these structures. Filling the nanotubes
by monomers and polymerizing them, results in nanorods, which were imaged by AFM.
P1-02
The Role of Substrate Priming in Hydrogen-Bonded Polymer Self-Assembly of Capsules
and Films
V. KOZLOVSKAYA, Sukhishvili, Department of Chemistry and Chemical Biology, Stevens
Institute of Technology, Hoboken, NJ, vkozlovs@stevens.edu
Growth of hydrogen-bonded multilayers is affected by substrate shape and charge as well as by
deposition conditions of a polycation precursor layer. The growth of strongly-bound poly(Nvinylpyrrolidone)/poly(methacrylic acid)(PVPON/PMAA) and weakly-bound poly(ethylene
oxide))/poly(methacrylic acid)(PEO/PMAA) systems is contrasted when these multilayers are
deposited onto bare or poly(ethylene imine) (PEI)-treated surfaces of CdCO3 crystals, colloidal
silica particles, or silicon wafers. While in the PVPON/PMAA system robust multilayer
deposition occurred on the precursor-treated substrate regardless of the adsorption history of the
precursor layer, growth of PEO/PMAA films was critically dependent on the conditions of PEI
adsorption. PEO/PMAA films could be grown on CdCO3 substrates when the PEI precursor was
allowed to adsorb at a pH value higher than that used for hydrogen bonding deposition, but
PEO/PMAA film growth was inhibited when PEI was deposited at the same pH used for film
deposition. This effect is rationalized in terms of the different structure and charge of precursor
layers formed through two deposition routes. Two ways to facilitate growth of hydrogen-bonded
multilayers onto substrates which carry unfavorably high negative charge have been suggested:
construction of PVPON/PMAA/PEO hydrogen-bonded multilayers and the use of divalent
cations as promoters of PMAA binding.
P1-03
Responsive Layers from Heteroarm Star Copolymer
R. LUPITSKYY, S. Minko1, C. Tsitsilianis2, 1Department of Chemistry, Clarkson University, 8
Clarkson Avenue, Potsdam, NY, 2Department of Chemical Engineering, University of Patras,
Patras, Greece
A grafted layer from poly(2-vinylpyridine)-star-poly(styrene) was prepared and its responsive
behavior and phase segregation has been studied using Atomic Force Microscopy, water contact
angle measurements, and X-ray Photoelectron Spectroscopy. The heteroarm star copolymer
consists of 7 polystyrene and 7 poly(2-vinylpyridine)-arms (PS7-P2VP7) emanating from one
core made of polymerized divinylbenzene. AFM studies revealed that single molecules of PS7P2VP7 respond to solvent quality by changing there conformation and, therefore, act as spherical
mixed polymer brushes. Grafted layers of PS7-P2VP7 exhibit very pronounced phase
segregation. It was shown that surface composition, morphology, and wettability of such layers
reversibly change in response to external stimuli such as solvents of different quality.
P1-04
pH-Sensitive Membranes from Polyelectrolyte Gels
M. ORLOV, S. Minko, I. Tokarev, Chemistry Department, Clarkson University, Potsdam, NY
Cross-linked polymers were used to obtain pH-sensitive membranes. The properties of the
membranes were further investigated. Membranes were prepared according to the principles of
phase separation in polymer blends. Depending on the composition of the blend, pores’ sizes
could be changed from hundreds of nanometers to several micrometers. The pore-size of the
membranes can be regulated by the change of the pH and ionic strength since they are formed
from polyelectrolytes. Membranes could be applied for controllable water transport or selective
filtration.
P1-05
Surface Plasmon Resonance Spectroscopy Study of the Adsorption of Surfactants to
Electroactive Interfaces
L. L. NORMAN, Antonella Badia, Department of Chemistry and the Centre of Self-Assembled
Structures, University of Montreal, Montreal, QC, Canada, lana.norman@umontreal.ca
Well-defined electroactive monolayer films have been prepared by the self-assembly of
ferrocenylalkanethiols on gold surfaces. These self-assembled monolayers (SAMs) allow one to
electrochemically modulate surface interactions such as adhesion and wetting, as well as induce
bulk orientation changes in liquid crystals through potential induced changes in the surface
charge density. In the present study a combination of electrochemical characterization and
surface plasmon resonance (EC-SPR) was employed to investigate the association of anionic
surfactants to an electroactive self-assembled monolayer as the redox active monolayer is
oxidized. SPR was used to quantify the thickness and the refractive index changes resulting
from ion pairing between the ferrocenium cation and the counter ion in the solution. We show
that the introduction of charges at an electroactive SAMs/solution interface can be used to
influence the surface assembly of ionic surfactants and control the molecular organization of
surfactants at SAM/solution interfaces.
P1-06
The Use of Self-Patterned Phospholipid Films for Directed Enzyme Lithography
N.Y.-W. TANG, A. Badia, FQRNT Centre for Self-Assembled Chemical Structures and
Department of Chemistry, University of Montreal, Montreal, QC, nathalie.tang@umontreal.ca
A novel method based on Langmuir-Blodgett deposition was developed for creating patterned
monolayer and bilayer films of phospholipids. Regular stripe patterns with dimensions of few
hundreds of nanometers over several square centimetre areas have been generated. Atomic force
microscopy (AFM) imaging demonstrated that the stripe patterns are composed of two
phospholipids in different phases (solid and fluid). These stripes are easily controlled in terms of
lipid composition, surface pressure, and film deposition conditions. In this poster, I will present
the mechanism of stripe formation and how the patterned dimensions can be controlled by using
lineactants and a combination of different lipids. Preliminary results on selective phospholipid
degradation using lipolytic enzymes will be discussed. This work expands the repertoire of
template composition and pattern form usable for the fabrication of lipid based surface patterns
and nanostrutures which could serve to spatially direct enzyme action and enzymatic
lithography, and design biomimetic membrane architectures.
P1-07
Fabrication and Study of Responsive Nanoparticles and Colloids
MIKHAIL MOTORNOV, S. Minko, Department of Chemistry, Clarkson University, Potsdam,
NY, mmotorno@clarkson.edu
We report the design and fabrication of smart particles and colloids capable for reversible
switching between hydrophilic and hydrophobic states upon external stimuli. Smart
nanoparticles are silica nanoparticles with specially designed responsive coating–mixed polymer
brush. The mixed brush consists of two unlikely polymers grafted to silica nanoparticles. Two
different polymers (A and B) in the mixed brush segregate to avoid unfavorable interactions. The
mechanism of phase segregation depends strongly on outside conditions. This adaptive behavior
of the mixed polymer brush can be used for engineering surfaces of smart nanoparticles. Polymer
A is a water soluble hydrophilic polymer, and the second polymer is a hydrophobic polymer B.
In aqueous medium the mixed brush will segregate. Polymer B will segregate to the core, while
chains of polymer A will be exposed to the outside. However, in nonpolar organic solvent
polymer B will segregate to the core and polymer A will form the outer shell of the particle. In
an intermediate case (nonselective solvent for both polymers), the lateral segregation takes place
resulting in semi spheres constituted from different polymers. The latter morphology will appear
if the particles are introduced into the interface between two immiscible liquids. The goal of this
research is to design smart spherical mixed brushes (nanoparticles) which will change the surface
characteristics of different materials due to the responsive behavior of the mixed brushes.
P1-08
Modification of Gold Nanostructures by Using Temperature-Sensitive Core-Shell Microgel
as a Template.
D. SUZUKI, H. Kawaguchi, Graduate School of Science & Technology, Keio University,
Yokohama, Japan, dai95@orion.ocn.ne.jp
We demonstrate the novel thermo-sensitive hybrid core-shell microgels via in situ synthesis of
gold nanoparticles using thermo-sensitive core-shell microgel as a template. The template coreshell microgels whose core were mainly composed of poly(glycidyl methacrylate) (GMA) and
shell mainly (or fully) composed of poly(N-isopropylacrylamide) (PNIPAM) were synthesized in
aqueous medium, and then they were incorporated with functional groups such as thiol, or amino
groups. By designing the template structures, we could obtain two types of hybrid microgels.
One is hybrid particles with gold nanoparticles localized around the core, and the other is the
particles with gold nanoparticles immobilized in the shell. They showed thermo-sensitive
properties, especially, in the latter case, the hybrid particles exhibited a reversible color change
from red to purple originated from surface plasmon resonance of gold nanoparticles depending
on temperature between 25 and 40 degrees. In addition to the thermo-sensitive property, the
hybrid particles exhibited unique character of regularly arrangement on solid substrate. The
particles obtained by this approach have potential uses for thermo-sensitive applications such as
sensor, photonic or electronic devices.
P1-09
Fabrication of Metal Nanostructures Using Self-Assembled Polymer Layers as Templates
I. TOKAREV, S. Minko, Department of Chemistry, Clarkson University, Potsdam, NY,
itokarev@clarkson.edu
Thin film templates with diverse nanopatterns were designed using the principles of phase
separation in polymer blends and block copolymers. The special feature of our approach is the
application of low molar mass additives which are easily extracted from the polymer films
leaving either nanochannels or nanotrenches. Sputter-deposition and electrochemical deposition
were used to fill the templates’ cavities with various metals. An additional control over the metal
deposition was achieved by an appropriate combination of polar and nonpolar polymer
components of the templates.
P1-10
Organization of Gold Nanoparticles on PS-PMMA Block Copolymer Monolayers
C. LEMAY, A. Ritcey, CERSIM, Department of Chemistry, Laval University, Quebec, QC,
Canada, cynthia.lemay@chm.ulaval.ca
Ordered arrays of metal nanoparticles exhibit unique properties that may lead to important
applications in the fields of optics and catalysis. The formation of periodic, ordered structures by
block copolymers is well known. Phase separation in block copolymers spread at the air-water
interface offers an interesting route to the preparation of patterned surfaces. For example,
polystyrene-b-poly(methyl methacrylate) forms ordered arrays of well-defined surface micelles
when spread at the air-water interface. These structures are conserved during monolayer transfer
to solid substrates by the Langmuir-Blodgett technique. Our current research focuses on the
subsequent organization of metallic nanoparticles on these ordered copolymer surfaces. Several
strategies are being investigated. One approach involves the organization of amine capped gold
particles on sulfonated polystyrene domains of the PS-b-PMMA monolayers. Water-soluble
gold nanoparticles are prepared by the phase transfer method with two ligands. Gold is reduced
by NaBH4 in the presence of (3-mercaptopropyl)-trimethoxysilane and the particles thus formed
are observed to pass into the organic phase. An amine terminated ligand is then introduced and
reacts via siloxane binding to produce water-soluble particles. A second strategy involves the
direct spreading of polystyrene capped gold particles with PS-PMMA at the air-water interface.
The ordered arrays are characterized by AFM and TEM.
P1-11
Composite Films Prepared by Single Wall Carbon Nanotubes Coated Monodisperse
Polymeric Microspheres.
YUN-HO LEE†, Bumsu Kim‡, Jee-Hyun Ryu†, Kyung-Do Suh†, †Division of Chemical
Engineering, College of Engineering, Hanyang University, Seoul, Republic of Korea, ‡Div. of
Inorganic Chemistry Exam, Bureau of Chemistry & Biotechnology Exam, Korean Intellectual
Property Office (KIPO), Daejeon, Republic of Korea, kdsuh@hanyang.ac.kr
Functionalized monodisperse micron-sized polymeric particles were coated with functionalized
single-walled nanotubes (SWCNTs). To coat functionalized SWCNTs on the surfaces of
particles, polymeric microspheres (poly (styrene-co-acrylamide)) having the amine group on
surfaces were synthesized by dispersion polymerization. SWCNTs were functionalized by
chemical oxidation, also. The composite films of SWCNTs coated microspheres were obtained
by using hot press at temperature over the Tg of microspheres. The morphology and the
properties of the SWCNTs coated microsphere were investigated by a scanning electron
microscope, infrared spectroscope, thermal analysis (differential scanning calorimetry,
thermogravimetric analysis) and zeta potential analysis. In addition, the conductivity, the
hydrophobicity and the morphology of composite films were investigated. The small amount of
SWCNTs (the weight of ratio polymer : SWCNTs = 500 : 1) coated on microspheres strongly
affects the physical properties of microspheres and composite films.
P1-12
Controlled Alignment of Single-Walled Carbon Nanotubes Using the Langmuir-Blodgett
Technique
Chul Youm, Sang-Keun Oh, SUNG-WOOK CHOI, Jae-Ho Kim*, Department of Molecular
Science and Technology, Ajou University, San 5, Wonchun-dong, Yeongtong-gu, 9, South
Korea, jhkim@ajou.ac.kr
The use of single-walled carbon nanotubes (SWNTs) as key building blocks for carbon-based
electronics has, in recent years, been demonstrated for a variety of applications such as fieldeffect transistors, field-emission materials and sensors. Many of these applications require the
integration of SWNTs into ordered macroscopic structures in a controlled way. Despite of
extensive efforts, however, it is still a challenge to fabricate large scale, highly organized
SWNTs onto solid substrates. Here we describe a method for generating aligned, patterned
SWNT structures over large areas using the Langmuir-Blodgett (LB) technique. We synthesized
thiophenol-modified SWNTs (SWNT-SHs) through the conventional method based on amidation
of oxidized SWNTs. The resulting SWNT-SHs were found to be soluble in organic solvents
including chloroform, which allowed the nanotubes to form a stable monolayer at the water/air
interface. We found that the compression of SWNT-SHs on a LB trough leaded to a uniform
SWNT-SH film, where SWNT-SHs were aligned parallel to the trough barrier. Moreover the
SWNT-SH Langmuir films can be subsequently transferred onto either homogeneous or prepatterned solid substrates to form aligned SWNT films. Importantly, the electrical conductivity
of the resulting SWNT-SH films parallel to the tube axis was found to be ~15 times higher than
that perpendicular to the axis, reflecting anisotropic electrical properties due to the uniaxial
alignment of individual SWNT bundles.
P1-13
Opportunities Brought by Cationic Fluorinated Surfactants in Tuning the Mesoporous
Silica Particle Architecture
BING TAN1, Stephen E. Rankin1, Sandhya M. Vyas2, Hans-Joachim Lehmler2, Barbara L.
Knutson1; 1Chemical & Materials Engineering, University of Kentucky, Lexington, KY,
2
Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA
Fluorinated surfactants are special due to the hydrophobic and lipophobic fluorinated chains.
These surfactants tend to assemble into aggregates and form novel “intermediate” mesophases
more easily than hydrocarbon surfactants. These properties should allow co-assembly with
ceramic precursors to create materials with a wider range of pore size and shapes than are
available from hydrocarbon surfactants. Fluorinated surfactants also possess processing
advantages for organic functionalization and supercritical carbon dioxide processing. We report a
comprehensive investigation of the use of cationic fluorinated surfactants as templates for
ordered nanoporous silica. A homologous series of cationic fluorinated surfactants with tail
lengths between 4 and 12 carbons is synthesized. Using these surfactants, materials are
synthesized either in aqueous solution or in water/ethanol solution. Silica powder with pore size
as small as 1.6 nm was obtained by using the C4 cationic fluorinated surfactant. This pore size is
the smallest among all pore sizes obtained from a surfactant templating process. Silicas with
hexagonal pore structure as well as random mesh phase and vesicles were synthesized. The
random mesh phase structure and the vesicle structure with mesoporous shells are the first time
to be reported. The variety of pore architectures found in this study is much greater than would
be found for a homologous series of hydrocarbon surfactants. We relate this structure variety to
the known variety of micelle aggregates and mesophases formed by fluorinated surfactants.
P1-14
Synthesis of Fluorocarbon Functionalized Mesoporous Silica Using Fluorinated Surfactant
Templates
GIFTY OSEI-PREMPEH1, Barbara L Knutson1, Stephen E Rankin1, Hans-Joachim Lehmler2,
1
University of Kentucky, Chemical and Materials Engineering, 177 Anderson Hall, Lexington,
KY, 2University of Iowa, 222 IREH, Department of Occupational and Environmental Health,
Iowa City, IA, bknutson@engr.uky.edu, gosei2@uky.edu
Cationic fluorinated surfactants have been successfully used as templates in the synthesis of
ordered porous silica materials by our group. This work explores the direct synthesis of organic
functionalized silica materials through fluorinated surfactant templating. The general templating
mechanism, in which the organic functional groups of the silica precursor are incorporated into
the micelle core, is favored by the surfactant and the organic functional group being of like
chemical nature. Therefore, in the case of fluorinated surfactant templating, a fluorocarbon
functional group may be well aligned within the silica pores. Investigation of direct synthesis of
C6F13C2H4-, C8F17C2H4- and C10H21- (for comparison) functionalized porous silica materials has
been performed. The materials were synthesized using cationic fluorinated surfactants,
C6F13C2H4NC5H5Cl and C8F17C2H4NC5H5Cl, and cetyltrimethylammonium bromide
(C16H33N(CH3)3Br-) as templates.
Fourier transform infrared spectroscopy (FTIR) analysis and TGA confirm the incorporation of
the functional groups in the materials after surfactant extraction. Powder X-ray diffraction,
transmission electron microscopy (TEM) and nitrogen adsorption analysis are used to
characterize the textural properties of the materials obtained from the four different combinations
of functional group and surfactant.
P1-15
Self-Assembly of Nanoporous Silica Shapes: Synthesis, Morphogenesis, and Applications
YA. YU. KIEVSKY, I. Yu. Sokolov, Center for Advanced Materials Processing, Department of
Physics, and Department of Chemistry, Clarkson University, Potsdam, NY,
kievskyy@clarkson.edu
We study the process of self-assembly of nano(meso)porous silica particles via surfactant
templating. Process of formation of the mesoporous silica includes growth of the liquid
crystalline template and solidification of this template via polymerization of silica precursor.
Material obtained as a result of such synthesis (MCM-41) features highly uniform porosity, a
large variety of shapes and their sizes. To control the assembly of the desired shapes, we study
their morphogenesis. New conditions of self-assembly are found to form monoshaped
nanoporous fibers. Recently suggested Origami-type mechanism for synthesizing a rich family of
nanoporous silica shapes (cones, tubes, and hollow helixes) is examined. Shape details and their
evolution are analyzed by means of XRD, SEM, TEM, AFM, and optical microscopy techniques.
The shapes can possibly serve as templates for various electronic and optical applications.
Nanoporous shapes are the prospective hosts for lasing dyes (sealing laser dye molecules inside
the silica pores saves them from oxidation and prevents their dimerization). Diffusion from the
nanoporous shapes can be used for a control drug release. Another application of mesoporous
silica is the coating of optical fibers by uniform low refractive index film with a good adhesion –
a possible host for laser dyes or quantum dots.
P1-16
Fabrication and Stabilization of Chain Structures from Fe3O4 Nanoparticles in the
Magnetic Field
ROMAN SHEPAROVYCH1, Yudhisthira Sahoo3, Mikhail Motornov1, I. Sokolov2, Paras N.
Prasad3, Sergiy Minko1, 1Department of Chemistry, Clarkson University, 8 Clarkson Ave.,
Potsdam, NY, 2Department of Physics, Clarkson University, 8 Clarkson Ave., Potsdam, NY,
3
Institute of Lasers, Photonics and Biophotonics, University at Buffalo, The State University of
New York, Buffalo, NY
A simple method of a magnetically induced formation of chain-like structures from magnetite
nanoparticles and a polyelectrolyte in aqueous solution was developed. Massart's co-precipitation
method was used for preparing of the aqueous solution of superparamagnetite (Fe3O4)
nanoparticles stabilized with citric acid. Chain structures were fabricated from the magnetite
nanoparticles in the applied magnetic field. The wires were stabilized with polyelectrolyte
molecules so that the structures conserve the shape upon dilution, centrifugation, and deposition
onto solid substrates. The stabilized magnetic wires were used to fabricate aligned structures by
applying external magnetic field. We demonstrate that this strategy could be used for the
fabrication of complex hierarchical structures.
P1-17
ESR Study on Nanomolecular Valve Effect of Cu Complex Crystal in Gas Adsorption
Koji Nakabayashi1, Hiroshi Noguchi1, Atsushi Kondo1, Aya Tohdoh3, Hiroshi Kajiro2,
HIROFUMI KANOH1, Katsumi Kaneko1, 1Chiba University, 1-33 Yayoi-cho, Inage, Chiba,
JAPAN, 2Nippon Steel Corporation, Futtsu, JAPAN, 3IRI, Takada, Kashiwa, JAPAN,
kanoh@pchem2.s.chiba-u.ac.jp
A microporous metal organic solid has a great advantage for designing and construction of the
porous framework appropriate for selective adsorption. Li and Kaneko found a remarkably
specific adsorption behavior of high reproducibility for CO2 in Cu complex-assembled
microcrystal [Cu(bpy)(BF4)2(H2O)2(bpy)]n (bpy = 4,4’-bipyridine) irrespective of no open
channels. CO2 is vertically adsorbed and desorbed at specific pressures at 273 K. Thus, this Cu
complex solid is denoted a latent porous copper crystal (LPC). Although the mechanism has not
been clear, the mechanism of the nanomolecular valve effect will be presented based on the
model structure in another paper in this symposium.
In the present study, the mechanism of the nanomolecular valve effect was examined by the ESR
measurement on Cu2+ of LPC before and after the gate adsorption of CO2. The ESR data show
the characteristics for monomeric species with axial symmetry before the gate adsorption. The
distances between atoms along z-axis are elongated longer than those between atoms in the xy
plane because of the Jahn-Teller effect. After the gate adsorption, LPC seems to change to a
more isotropic octahedral structure, probably accompanied by the shrinkage of the bond distance
along z-axis.
AGGREGATION AND DEPOSITION OF COLLOIDAL PARTICLES
P2-01
Influence of Anions on Formation of -FeOOH Particles
T. ISHIKAWA1, S. Miyamoto1, K. Kandori1 and T. Nakayama2, 1School of Chemistry, Osaka
University of Education, 4-698-1 Asahigaoka, Kashiwara, Osaka, Japan, 2Materials Research
Laboratory, Kobe Steel, LTD., 5-5 Takatsukadai 1-chome, Nishi-ku, Kobe, Hyogo, Japan,
ishikawa@cc.osaka-kyoiku.ac.jp
-FeOOH particles in environments containing of Cl- such as marine and
coastal districts where steels are easily corroded. Besides Cl- ions, various anions such as SO42and NO3- result from SOx and NOx in the atmosphere and SiO32- exists in soils, and also PO43- is
contained in surface treatment agents of steels
-FeOOH particles were
synthesized by oxidation of FeCl2 and hydrolysis of FeCl3 in solutions containing different
anions. The resulting particles were characterized by various techniques. The crystallite sizes
obtained by XRD steeply decreased with the addition of SO42- and HPO42- in Fe(II)-oxidation
and Fe(III)-hydrolysis. The particle morphology turned from rod to irregular shape on adding
SO42- and the addition of SiO32- increased the particle size. The presence of HPO42- also
increased the particle size in Fe(II)-oxidation but decreased it in Fe(III)-hydrolysis. The pore size
distribution obtained by N2 adsorption showed that the products with SO42- in Fe(II)-oxidation
were microporous but those in Fe(III)-hydrolysis were mesoporous.
P2-02
Synthesis of Lanthanide Fluoride Nanoparticles of Varying Shape and Size
JEAN-LUC LEMYRE, Anna M. Ritcey, Département de chimie and CERSIM, Université Laval,
QC, Canada, lemyre@chm.ulaval.ca
Recent scientific literature demonstrates a growing interest in new methods of nanoparticle
synthesis, driven primarily by an ever increasing awareness of the unique properties and
technological importance of nanostructured materials. Major issues associated with nanoparticle
preparation include the control of particle size and internal structure. We have explored several
synthetic routes for the preparation of nanoparticles containing rare earth elements. The
fabrication of nanoparticles within reverse microemulsions has been shown to be a convenient
route to monodisperse particles of controllable size. Yttrium fluoride nanoparticles of varying
crystallinity, shape and size are prepared by precipitation in reverse microemulsions of water in
cyclohexane stabilized with polyoxyethylene isooctylphenyl ether. YF3 particles obtained by the
classical microemulsion method are found to be monodisperse amorphous spheres, with
controllable diameters between 6 and 50 nm. Furthermore, particles of the same material
obtained by a relatively minor variation of this method are found to be monodisperse single
crystals of octahedral and triangular shapes. The size of the crystalline particles can be varied
between about 25 and 350 nm. The formation of single crystals can be attributed to the slower
incorporation of the precipitant into the micelles when introduced in this fashion.
P2-03
Synthesis of Copper (I) Oxide and Metallic Copper Particles in Polyols
A.Anžlovar, Z. CRNJAK OREL, M. Žigon, National Institute of Chemistry, Hajdrihova 19, SI1000 Ljubljana, Slovenia, zorica.crnjak.orel@ki.si
Polyol-mediated synthesis was used for the conversion Cu (II) in to Cu (I) oxide and metallic Cu.
Cu acetate (0.001-0.04 mol/l) either in di(ethylene glycol) (DEG) or in 1,2-propane diol (PD)
was heated close to the boiling temperature of polyols for different periods of time. The chemical
composition, average particle size, and morphology were studied (SEM microscopy, X-ray
diffraction and FT- IR spectroscopy) in dependence of the temperature, the polyol used and the
concentration of precursor. In DEG copper (I) oxide forms nanorod consisted spheres, that
collapse into individual nanorods and they decompose and form irregular shaped metallic Cu
particles (30 – 200 nm). In PD copper (I) oxide intermediate forms particles (100-300 nm)
composed of small units (10-20 nm). With further heating particles become hollow and Cu
particles (100 – 700 nm) are formed. The occurrence of hollow structures in DEG and in PD may
indicate that transformation of Cu (I) oxide to Cu involves dissolution of the oxide structure (1).
The band at 620 cm-1 due to optically active lattice vibrations in oxide was obtained only when
the reduction temperature was lower than195 oC in DEG and 175 oC in PD.
P2-04
Coprecipitation of Composite Colloidal Compounds Copper and Zinc Basic Carbonates
ZORICA CRNJAK OREL1, Jadran Maček2, Marjan Marinšek2 Stane Pejovnik2, Egon
Matijević3, 1National Chemical Institute, Ljubljana, Slovenia , 2University of Ljubljana, Faculty
of Chemistry and Chemical Technology, 3Clarkson University, Potsdam, NY,
zorica.crnjak.orel@ki.si
Previously it was shown that uniform colloidal spheres of mixed metal oxides could be prepared
by coprecipitation in solution of metal salts, but the resulting particles were internally
inhomogeneous.
This study describes the formation of composite copper/zinc basic carbonates by decomposition
of urea in solutions of two metal nitrates in different molar ratios. This system is of particular
interest because the copper compound yields spherical and zinc rod-like particles when formed
individually under the same conditions. It was found that in the majority of cases by using
solutions of both metal salts and ageing them for 90 minutes, the resulting particles are spherical
with only a small fraction (1-3%) being zinc base carbonate. Only when zinc nitrate was at least
in four fold excess, the obtained solids appear as spherical assemblies formed from nanoribbons.
In these instances the selected area diffraction shows that such particles contain up to 80% of the
zinc compound.
The particle size increases with the reaction time, most likely by the Ostwald ripening. At still
longer aging times (180 minutes) spherical shapes consisting of nanoribbons (zinc base
carbonate) are formed.
P2-05
Preparation of the Au Nanoparticles Using NaHCO3 as a Reducing Agent
YOUNG-HO LEE, Dae-wook Kim, Seong-geun Oh, Division of Chemical Engineering and
Center for Ultramicrochemical Process System (CUPS), Hanyang University, Seoul, Korea,
nanoyh@ihanyang.ac.kr
In this paper, the Au nanoparticles were synthesized by polyol process with NaHCO3 (sodium
hydrogen carbonate) as a reducing agent. Utilizing NaHCO3 in polyol process achieved the low
reaction temperature and the short reduction time. Decomposition of NaHCO3 serves carbonate
ions (CO32-) and a small amount of H2O which dissolves the carbonate ions in. Carbonate ions
increase pH of the mixtures and accelerate the reduction rate of AuCl4 . In our experiments, the
effects of the NaHCO3/Au weight ratio and the PVP concentration on the reduction rate of
AuCl4 and the particle size of the Au nanoparticles were investigated. The NaHCO3/Au weight
ratio was varied to 10, 5, 3, 1 and 1/5. The reduction rate of AuCl4 was observed by the speeds
of the color changes of the mixtures. UV-vis spectra and TEM images indicated that the size of
the Au nanoparticles was controlled by the NaHCO3/Au weight ratio and the PVP concentration.
P2-06
Synthesis of Nanocrystals in Ionic Liquids
YONG WANG, Hong Yang, Department of Chemical Engineering and Laboratory for Laser
Energetics,
206
Gavett
Hall,
University
of
Rochester,
Rochester,
NY,
hongyang@che.rochester.edu
Ionic liquids (ILs) were used in the synthesis of nanostructured CoPt alloys with different
compositions and shapes ranging from nanorods, to hyperbranched nanorods and to spherical
nanoparticles. The 1-butyl-3-methylimidazolium bis(triflymethyl-sulfonly) imide ionic liquid,
[BMIM][Tf2N] was employed as the solvent and the reaction was typically conducted at 350 °C
under the protection of argon. Platinum acetylacetonate (Pt(acac)2) and cobalt acetylacetonate
(Co(acac)3) were used as the precursors. The morphology, composition and crystal phase of the
resulting CoPt alloy nanocrystals could be controlled by changing the concentration and molar
ratio of the platinum and cobalt precursors. The rods synthesized were found having a
composition of CoPt using powder X-ray diffraction (PXRD) and energy dispersive X-ray
(EDX) spectroscopy. The nanoparticles were found to be CoPt3. PXRD, EDX, HR-TEM and
micro-electron diffraction (ED) were also used in the characterizations of these nanocrystals.
P2-07
Uniform Ag and AgPd Nanoparticles for Ultra-Thin Conductive Metallic Layers
B. P. FARRELL, D. V. Goia, Center for Advanced Materials Processing and Department of
Chemistry, Clarkson University, Potsdam, NYgoiadanv@clarkson.edu
The aggressive reduction in materials costs and the relentless drive to increase the specific
volumetric capacitance are two of the most important trends that characterize multi-layer ceramic
capacitor technology. Here we present a novel precipitation process capable of generating highly
dispersed Ag and AgPd, core-shell, nanoparticles that can be used to construct ultra-thin (150-200
nm) uniform conductive layers and could pave the way for capacitors with a very high number of
electrodes and, therefore, high volume capacitances. Characterization of the particles by Field
Emission SEM, X-ray Diffraction, TGA and Laser Diffraction Particle Size Analysis confirms the
high purity of the metallic phase and reveals the high degree of uniformity and dispersion of the
resulting particles. The precipitation process developed allows for the deposition of Pd shells
representing 2-30 wt%, and is suitable for large scale manufacturing. A novel deposition technique
that can be integrated along with these materials in the existing MLCC manufacturing lines with
minimal disruption and in a cost effective manner, is also proposed.
P2-08
Multi-Layer Microfluidic Device to Assemble Uniform Colloidal Clusters and Double
Emulsions
HUA HU, Steven D. Hudson, Polymers Division, National Institute of Standards and
Technology, Gaithersburg, MD, huahu@nist.gov
We fabricated a novel multi-layer PDMS microfluidic device, which integrates a valve and a
Coulter counter, to prepare uniform colloidal assemblies and double emulsions. First, bonding
techniques, such as oxygen plasma and a chemical bonding method, and their effects on the
bonding strength between two PDMS layers were investigated systematically by monitoring
fracture pressure. Second, in this multi-layer device, we developed a novel valve that can stop
flow in a microchannel with arbitrary width and depth. The efficiency and the response of the
valve are reported. The in-line Coulter counter signals actuation of the valve to prepare
controlled-size colloidal assemblies or double emulsions that contain a uniform number of
particles or droplets. These advanced structures are expected to have broad applications and
significant impact in optical materials and biomaterials.
P2-09
Heteroaggregation Rates and Light Scattering Form Factors of Asymmetric Particle
Doublets by Multi-angle Static and Dynamic Light Scattering
W. LIN, P. Galletto, M. Borkovec, Laboratory of Colloid Surface Chemistry, Department of
Inorganic, Analytical, and Applied Chemistry, University of Geneva, Sciences II, 30 Quai
Ernest-Ansermet, 1211 Geneva 4, Switzerland, wei.lin@unige.ch
Heteroaggregation denotes aggregation processes in which particle charge and/or size are
different. Such phenomena are of greater relevance in applications and natural environments than
the analogous processes with identical particles (i.e., homoaggregation). In spite of their
relevance, however, heteroaggregation has not been studied much. In this work, the
heteroaggregation of two oppositely charged polystyrene latex particles is followed by timeresolved simultaneous static and dynamic light scattering (SSDLS), and from its initial time
dependence we can obtain absolute aggregation rates and extract the form factor of the doublets.
The heteroaggregation rates are obtained by analyzing the SSDLS data without the need to
invoke the optical form factors for the doublets. The experimental form factors are compared
with independent calculations based on the T-matrix method and the Rayleigh-Debye-Gans
(RDG) approximation. While the RDG approximation is found to be reliable only up to particle
diameters of about 250 nm, the superposition T-matrix method is very accurate for all types of
doublets investigated, which shows clearly the appropriateness of the T-matrix method to
estimate the optical properties of colloidal particles in the micrometer range reliably.
P2-10
Colloid-Colloid and Colloid-Surface Mass Transport Relaxational Kinetics
A. CADILHE, N. Araújo, GCEP-Centro de Física, Universidade do Minho, 4710-057 Braga,
Portugal, cadilhe@fisica.uminho.pt
We present preliminary results of a Monte Carlo study of mass transport between colloidal
particles and colloidal particles and the substrate. Colloidal particles growth has recently taken
notorious advances in the literature, but their contact with other particles and to the substrate
leading to restructuring has been less studied from a theoretical perspective. We quantify the
time scales involved during the restructuring of both particles or between the particle and the
substrate. Our study may also shed some light into the ripening of colloids.
P2-11
Measuring Heteroaggregation Rate Constant of Binary Particle Suspension in the Presence
of Homoaggregation
WEILI YU1, M. Borkovec2, 1Pfizer Groton Laboratories, Pfizer Inc., Groton, CT, 2Department of
Inorganic, Analytical, and Applied Chemistry, University of Geneva, 30, Quai Ernest-Ansermet,
1211 Geneva 4, Switzerland, yuw@groton.pfizer.com, michal.borkovec@unige.ch
Heteroaggregation between particles of different sizes and properties plays an important role in
various applications, such as medicine, ceramics, filtration, flotation, and water purification. In
this study, the time-resolved multiangle simultaneous static and dynamic light scattering is used
to measure absolute heteroaggregation rate constants in aqueous binary colloidal particles
mixtures despite the simultaneous occurrence of homoaggregation. The differences in the form
factor of asymmetric dimmers were exploited by using particles of unequal sizes in the range of
100-200 nm, where the Rayleigh-Gans-Debye approximation is accurate. The formation
aggregation rate constant for the asymmetric dimmers as a function of the ionic strength was
studied up to 300mM.
P2-12
A Coupled Coagulation Model with Arsenic Sorption Kinetics and Equilibrium
on Fractal Colloids of Hydrous Ferric Oxide (HFO)
JIN-WOOK KIM, Timothy A. Kramer*, Department of Civil Engineering, Texas A&M
University, College Station, TX, tkramer@civilmail.tamu.edu
In recent years, numerous studies have attempted to solve the continuous population balance
equations (continuous integro-particle differential equations). To obtain numerical solutions of
the continuous population balance equations, extensive computation time and hardware are
required. A realistic maximum size used in coagulation modeling would therefore produce an
unmanageable number of simultaneous equations to solve. To overcome this computational nonefficiency of the uniform discrete model, various non-uniform discrete schemes have been
introduced.
An improved discretized population balance equation (PBE) is proposed in this study. This
improved discretized population balance equation has new probability distribution functions for
aggregates produced in non-uniform discrete coagulation modeling. In this study, this model was
found to be a substantial improvement in terms of numerical accuracy, stability, and
computational efficiency over the continuous model. Further, this model was able to simulate the
particle aggregation and breakup with fractal dimensions lower than 3. Moreover, comparisons
were made using the fractal aggregate collision mechanisms of orthokinetic coagulation with the
inclusion of flow induced breakup. This new algorithm makes it possible to solve fractal particle
aggregation and breakup problems with high accuracy, perfect mass conservation and
exceptional computational efficiency, thus the new model can be used to develop predictive
simulation techniques for the coupled coagulation using computational fluid dynamics (CFD)
and chemical reaction modeling.
In this study, this improved coagulation model developed was coupled with arsenic sorption
equilibrium and kinetics on fractal colloids of hydrous ferric oxide (HFO). The model coupling
was achieved by using the colloid stability factor of W(ri , r j ) and/or particle collision efficiency
α(ri , r j ) as one component of the aggregation rate constant ( kagg  αβ ) and a main function for
coupling coagulation model with chemical reactions such as arsenic sorption. The study
reviewed the collision efficiency studies for perikientic and orthokientic mechanisms and
provided the numerical algorithms to calculate collision efficiency for two different transport
mechanisms, depending on two colliding particle geometric sizes and surface potentials or
surface charges. Finally, unified model that is coupled coagulation modeling with arsenic
sorption kinetics consisting of a sorption diffusion transport model and surface complexation
model was developed. Using the coupled model developed in this study, it was possible to
predict arsenic sorption (equilibrium and kinetics) and colloid particle collision (surface potential
time evolution, coagulation kinetics and particle size distributions) during the arsenic sorption
and coagulation, simultaneously.
P2-13
Shape Controlled Growth of Colloid Particles: Numerical Simulation
Dan V. Goia1, V. Gorshkov2, S. Libert2, E.Matijevic1, V.Privman2, I. SEVONKAEV2,
1
Department of Chemistry, 2Department of Physics, Clarkson University, Potsdam, NY
In this study we proposed a combinational mechanism of the shape control particle growth. We
assume that the aggregation consists of two main processes: deposition, and
rearrangement. Numerical simulation analysis was used to study the parameters of the shape
maintained growth of the initial particles. The Gaussian distribution function (GDF) was
proposed as the main deposition rule for the arriving building blocks. Uniform distribution
function (UDF) was suggested as the main mechanism for the rearrangement. Two main
parameters: the standard deviation σ and the ratio of deposition ρ have been chosen for the shape
maintained growth manipulation. The simulation showed that the combination of parameters σ =
0.5
and
ρ
=
0.2
gives
adequate
results
up to 20,000 deposited building blocks; this corresponds to the growth of the initial particle twice
in volume. Additional rules for further study are proposed.
P2-14
Preparation Methods and Infrared Attenuation Capabilities of Highly Conductive
Anisotropic Metallic Particles
D. LE, C. Goia, D.V. Goia, Center for Advanced Materials Processing, Clarkson University,
Potsdam, NY, goiadanv@clarkson.edu
In the present work we have prepared highly conductive anisotropic metallic particles and
investigated the ability of their aerosols to scatter and absorb infrared radiation. Copper and
silver flakes of high aspect ratio were produced by milling spherical particles of the respective
metals. Additional treatments, such as silver coating by conventional galvanic displacement,
have been applied to the copper flakes to enhance their dispersion, chemical stability, and
attenuating properties. It has been found that during the silver deposition by electrodisplacement with metallic copper, silver fibers can form. The formation of these fibers occurs
through the growth of the silver clusters at the expense of the copper substrate, their properties
being strongly affected by the size and shape of the latter. Mass extinction values for the
metallic platelets and fibers were calculated from transmittance measurements acquired by
Fourier transform infrared spectroscopy.
P2-15
Control of Micro-Spheroid Silica Structure and Organic Functionalization via a Sol-Gel
Method in W/O Emulsion
Y. G. LEE, C. Oh, S. G. Oh, Department of Chemical Engineering, Hanyang University, 17
Haengdang-Dong, Seongdong-gu, Seoul, seongoh@hanyang.ac.kr
A controlled fabrication of silica materials with micro-spheroid type of structure containing a
layer of organic functional groups outside the surfaces by using a sol-gel method in W/O
emulsion was designed. The presence of Pluronic P123 and surfactants during the acid-catalyzed
condensation greatly influenced the final particle morphology.
When Pluronic P123 copolymer was used in the W/O emulsion under the low pH condition, 2 or
3 of water droplets were linearly arranged and inter-condensation of hydrolyzed TEOS
molecules occurred. Depending on the surfactants such as non-ionic (Span 80 or AOT), anionic
(SDS), cationic (CTAB), used in the aqueous phase, the particle morphology was changed
because of the interaction between silica sols and surfactants, including rod-type or egg-type
structure. To combine thiol or amine group with the surface of silica particles, 3-mercaptopropyl
trimethoxysilane (MPTMS) or 3-aminopropyl trimethoxysilane (APTMS) were used. All
samples exhibited characteristic Type II BET isotherms, consistent with non-porous materials.
The structure and functionality of these materials were characterized by field-emission scanning
electron microscopy, fourier transform infrared spectroscopy, nitrogen adsorption and
desorption, optical microscopy, and Energy-dispersive X-ray.
GENERAL PAPERS IN COLLOIDS AND SURFACE SCIENCE
P3-01
Hydrophobically Modified Polyvinylamine and Poly (ethylene oxide)-Poly (propylene
oxide)-Poly (ethylene oxide) Complexes
YI WANG, Xiaonong Chen, Robert Pelton, Centre for Pulp and Paper Research, McMaster
University, Hamilton, ON, Canada, wangyi@mcmaster.ca
Aqueous solution properties of hydrophobically modified polyvinylamine (HMPVAm) and the
formation mechanism of HMPVAM / poly (ethylene oxide)-poly (propylene oxide)-poly
(ethylene oxide) (PEO-PPO-PEO) triblock copolymer complex were studied by dynamic light
scattering and fluorescence. The HMPVAm was synthesized by the reaction of polyvinylamine
(PVAm) with alkyl bromides. The solution properties of HMPVAm were explained in terms of
the balance of hydrophobic interactions and electrostatic repulsion. The influences of the
HMPVAm degree of substitution (DS) and solution pH on HMPVAm conformation were
significant. Higher DS and pH resulted in a more compact structure. HMPVAm / PEO-PPO-PEO
complex solutions were further investigated by dynamic light scattering and fluorescence
spectroscopy. Significant changes of light scattering intensity, polymer equivalent size and
fluorescence intensity ratio (I1/I3) were observed. These results suggested that the HMPVAm and
PEO-PPO-PEO complex formation was driven by hydrophobic interactions.
P3-02
Surface modification of EPDM rubber by plasma treatment
K.F. GRYTHE, F.K. Hansen, Department of Chemistry, University of Oslo, P.O.Box 1033
Blindern, 0315 Oslo, Norway, k.f.grythe@kjemi.uio.no
The effect of plasma treatment of thin, solvent cast EPDM films has been investigated by means
of AFM, XPS and Surface Energy Measurements. Argon, oxygen and nitrogen plasma was used,
and the changes in the surfaces were observed as function of treatment conditions and storage
times. A modified surface is normally stable, but some treatment conditions also can lead to
unstable surfaces. Surface energies were calculated from advancing contact angle measurements
by different methods. Plasma treatment lead to changes in the surface energy from 25 up to 70
mN/m, but the absolute values for the surface energies depended on the method used for
calculations.
XPS analyses of the modified surfaces revealed that up to 20wt% oxygen can be easily
incorporated in the surfaces, and that variations on the order of 5wt% can be controlled by the
plasma conditions. Oxygen was mainly found as hydroxyl groups, but also carbonyl- and
carboxyl oxygen functionalities were seen.
AFM measurements revealed different surface structures with the three gases that were used. The
surface roughness increased generally with treatment time, and dramatic changes could be
observed at longer times. At short times, however, surface energy changes were much faster that
the changes in surface structure, showing that plasma treatment conditions can be utilized to
tailor both surface energies and surface structure of EPDM rubber.
P3-03
AFM Visualization of Polyelectrolyte Single Molecules under Aqueous Media
YU. ROITER, S. Minko, Department of Chemistry, Clarkson University, Potsdam, NY,
sminko@clarkson.edu
We report on in situ AFM experiments for the visualization of single polyelectrolyte molecules
adsorbed on the mica substrate under aqueous environment at different pH and ionic strength. In
this experiments we study a weak polyelectrolyte poly(2-vinyl pyridine) when the conformation
is affected by the charge density on the polyelectrolyte molecule. The charge density is tuned by
change of pH of the aqueous solution and ionic strength (regulated by salt). The experiments
allows for the in tact study of the polyelectrolyte conformation introduced by the environment as
well dynamic changes of the conformation upon tuned environmental conditions. We compare
the conformations obtained in the in situ experiments and the conformations of the molecules in
a dry state upon solvent evaporation.
P3-04
Antifreeze Protein: from Interfacial Structure to Antifreeze Effect
NING DU, Xiang Y. Liu, Choy L. Hew, Biophysics & Micro/nanostructures Lab, Department of
Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore,
phydn@nus.edu.sg
Antifreeze Proteins (AFPs), occurring in some polar animals and plants, are capable of inhibiting
ice freezing at subzero temperatures. The antifreeze effect of Antifreeze Proteins on ice
nucleation, which was neglected in most studies, was examined based on a “micro-sized ice
nucleation” technique in this study. It follows from our experiments antifreeze proteins can
inhibit the ice nucleation process by adsorbing onto both the surface of ice nuclei and dust
particles, which leads to an increase of the ice nucleation barrier and the desolvation kink
kinetics barrier, respectively. It was found that the antifreeze activity of AFPs can be enhanced
either by their aggregation at higher concentration or by adding electrolyte into AFPs solutions.
This promotion in antifreeze activity is attributed to the rise of surface activity for AFPs
aggregates compared to AFPs monomers, and the screening effect of electrolyte to the surface
charge of AFPs molecules, respectively. This study enables us to obtain a comprehensive
understanding on the antifreeze mechanism of AFPs for the first time.
P3-05
Influence of Ammonia Vapor Post-Treatment on the Porosity of Mesoporous Silica
Prepared with Mixed Cationic and Glycoside Surfactant via Nanocasting
R. XING, S. E. Rankin, Chemical and Materials Engineering Department, University of
Kentucky, Lexington, KY, srankin@engr.uky.edu.
2D-hexagonal structured mesoporous silica samples with variable pore size are synthesized via
an acid-catalyzed nanocasting technique using mixtures of cationic and glycoside surfactants,
CTAB and n-Octylβ-D-glucopyranoside (C8G1). The pore diameter can be tuned by posttreatment of the as-made materials using NH3 vapor at a mild temperature of 50 °C. Without
ammonia treatment, the pore size distribution of silica materials remain almost the same,
independent of the ratio of C8G1 to CTAB. XRD and TEM indicate only a slight decrease in
long-range order. However, the composition of C8G1 greatly affects the pore size distribution
and degree of long-range order of the materials when the as-made materials are treated by
exposing them to vaporized aqueous ammonia. To study the influence of ammonia vapor postsynthesis on the porosity in these samples, two key factors are varied: the amount of silica
precursor and the amount of NH3 vapor. Based on the results, we propose that the results cannot
be explained entirely by a difference in the interaction between silica and cationic or nonionic
surfactants at elevated pH. Instead, we propose that the Maillard reaction takes place during
ammonia treatment, leading to an increase in pore size but also to a loss of long-range order.
P3-06
ATR-FTIR Study of Adsorption and Structural Arrangement of an Anionic Fluorinated
Surfactant at Germanium/Water Interface
R. XING, S. E. Rankin, Chemical and Materials Engineering Department, University of
Kentucky, Lexington, KY, srankin@engr.uky.edu.
Adsorption of anionic fluorinated surfactants, tetraethylammonium perfluorooctylsulfonate
(TEA-FOS) onto hydroxylated germanium from aqueous solution is studied in situ using
polarized attenuated total reflection FTIR spectroscopy. At pH 6.0, slow and extensive
adsorption leading to multilayer formation is observed for a series of bulk solution
concentrations spanning from 10% of the critical micelle concentration (1.0 mM) to well above
the cmc. Three kinetic stages, with an autoaccelerating last stage, are observed by monitoring
the intensity of the fluorocarbon bands. Circular dichroism measurements of CF2 stretching
bands indicate a slight orientation of the fluorocarbon director normal to the surface as
adsorption proceeds, but not perfect close-packed layer formation. Further studies indicate that
both pH and salt concentrations have significant effect on the adsorption kinetics as well as
structural arrangement. With increase of pH, the final surface coverage decrease. However, at
even pH ~10, far above the IEP of germanium, the adsorption of anionic surfactant onto
negatively-charged surface still can be observed, which indicates that the tetraethylammonium
ions mediates the interactions between the surfactant head groups and the surface. The presence
of salt increases the initial adsorption rate and change the sequence of steps leading to multilayer
formation.
P3-07
Direct Study of Interaction of a Single Nanoparticle with Surfaces by the AFM
QUY K. ONG, Igor Sokolov, Physics Department, Clarkson University, Postdam, NY,
isokolov@clarkson.edu
Study of interactions of nanoparticles with various surfaces is of great interest for modern
nanotechnology. For the first time, we present a new method to measure such interactions
directly. By immobilizing nanosized particles onto the tip of atomic force microscopy (AFM),
we are able to carry out direct measurements of the particle interaction with various surfaces.
Interactions of ceria nanoparticles and either silica or polyurethane surfaces are demonstrated.
The results are applicable to Chemical-Mechanical planarization (CMP). The fundamental issue
of interaction between silica nanoparticles and silica plane wafer is addressed by connection of
adhesion and long-range forces. We measure both types of forces by means of the AFM in
aqueous solutions of various acidities.
P3-08
A Simple and Convenient Method for the Measurement of Electrokinetic Mobility Using a
Moving Boundary Method
MASATAKA OZAKI,1,2* Teppei Ishikawa2, Dashdondog Bayarama2, 1Department of
Environmental Science and 2Graduate School of Integrated Science, Yokohama City
University,Kanazawa-ku, Yokohama, Japan, ozaki@yokohama-cu.ac.jp
Zeta potential is essential for the study of the stability of hydrophobic colloids, and a variety of
methods are used for the measurement of the potential. Among them electrophoresis is
frequently used. Although many apparatuses for the measurement of the potential are
commercially available, most of them are not only expensive but also some of them are not
available for small particles in nano-scale. We developed a simple and convenient apparatus for
the measurement of electrokinetic mobility using moving boundary method. In this method, a
sharp boundary could be created automatically under a flat metal plate or a semi-permeable
membrane. This method is not only convenient for the measurement of electrokinetic mobility
but also applicable to dispersions of nano-scale particles.
P3-09
A New Approach to Investigate the Deposition of Submicronic Particles by Laser
Reflection
C. Pignolet, F. Membrey, C. Filiâtre, M. Euvrard, C.PARNEIX, A. Foissy, Laboratoire de
Chimie des Matériaux et des Interfaces, Université de Franche-Comté, Besançon, France,
celine.pignolet@univ-fcomte.fr
The electrophoretic deposition of micrometer to nanometer size range colloidal particles onto an
electrode in aqueous media can result in an ordered array of particles. Such structures are very
attractive in a large range of applications: coatings, optical devices, biosensors… In a former
investigation, electrodeposition of micronic polystyrene particles on a nickel electrode in a dc
electric field was studied. The deposition was observed in situ in a laminar flow cell using
optical microscopy. The purpose of the present work is to extend these investigations to the
submicronic range of particle size. For that purpose we have developed an experimental setup
based on the reflection of a laser beam on the electrode surface. In order to validate the
procedure, preliminary experiments were performed using micrometric particles, which could be
simultaneously observed with both the regular microscope and the reflection apparatus. A
correlation between the two techniques was experimentally and theoretically established, leading
to the calibration of the system. This new approach allows in situ investigations of the
electrodeposition of nanometric particles (in the range of a few hundred nanometers).
P3-10
Millisecond Time Resolved Neutron Reflection Studies of Electrochemical and Surfactant
Systems.
J.M. Cooper, R. Cubitt, R.M. DALGLIESH, N. Gadegaard, A. Glidle, A.R. Hillman, Y.G.J. Lau,
E.A. Mas, R.J. Mortimer, R.M. Richardson, D.J. Riley, K.S. Ryder, E.L. Smith, ISIS, Rutherford
Appleton Laboratory, Chilton, Didcot, Oxfordshire,United Kingdom, r.m.dalgliesh@rl.ac.uk
By synchronizing data collection on a pulsed or chopped neutron source with the application of
an external stimulus to a sample it has now become possible to study neutron reflection on time
scales from milliseconds to tens of seconds. Recent measurements performed on the CRISP
reflectometer at ISIS and the D17 reflectometer at the ILL have investigated the dynamics of the
oxidation and reduction of polyvinylferrocene (PVF), the adsorption and desorption of Sodium
dodecylsulfate (SDS) at a gold interface and the switching of a nematic liquid crystal phase.
Unlike many other surface sensitive techniques neutron reflection has revealed information about
the internal dynamics of PVF at an in-situ solvated interface. The use of isotopic substitution
(H2O/D2O) allows a unique determination of the solvent and polymer depth profiles and has
revealed rate dependent effects in the solvation and desolvation of the polymer film. The
continuing development of this neutron reflection technique will add significantly to the
information which may be obtained from electrochemical systems as it may be used to probe the
relationship between the individual components.
NANOPARTICLES AND COLLOIDS IN ANALYSIS
P4-01
Modeling and Laboratory Column Study of Transport of Polydisperse Colloids through
Saturated Porous Media
S. PEDDIREDDY, J. Ren, Department of Environmental and Civil Engineering, Texas A&M
University-Kingsville, Kingsville, TX
Colloid transport through saturated porous media has been studied by many researchers due to its
importance in facilitating the transport of highly adsorbing contaminants in subsurface.
However, much of the work has assumed monodisperse colloids. It is well known that natural
colloidal particles are normally highly polydisperse. Recent studies have also shown the
importance of the advances in understanding the transport of polydisperse colloidal suspensions
on the analysis of contaminant transport in streams and pore waters. In this work, we conducted
both laboratory column experiments and numerical simulations to study the transport of
polydisperse colloids through saturated porous media. Both colloid concentration and particle
size distribution of effluent samples collected at the end of the column were measured
continuously over time. A polydisperse colloid transport model was developed to simulate the
effluent colloid concentration and temporal particle size evolution by considering processes
including advection, dispersion, and dynamic colloid filtration. The preliminary experiment
results clearly showed a decreasing of particle size over time and a significant higher colloid
deposition when background electrolyte concentration was high. The polydisperse colloid
transport model was used to simulate both the effluent particle concentration and particle size
distribution.
P4-02
Surface Immobilization of Individual Ag Nanoparticles for SERS-based Chem/Bio Sensing
S. TAN, D.Pristinski, M. Erol, H. Du, S. Sukhishvili, Department of Chemical, Biomedical and
Material Engineering; Stevens Institute of Technology, Hoboken, 1 Castle Point on Hudson, NJ,
stan@stevens.edu
We report a study on polymer-mediated immobilization of non-aggregated Ag nanoparticles on
planar glass substrates and the resultant surface-enhance Raman scattering (SERS) activity using
Rhodamin 6G (Rh6G) as a model molecule. Ag colloidal solution with an average particle
diameter of 70 nm was prepared by citrate reduction of AgNO3 using Lee-Meisel method and
subsequent fractionation. Self-assembled polyallylamine hydrochloride (PAH) monolayer was
employed as the intermediate polymer layer. We have shown that the coverage density of Ag
nanoparticles on the glass substrates correlates with the amount of adsorbed PAH. This
parameter can be easily controlled by varying the pH and ionic strength during polymer
deposition, with pH 9.0 and 0.25 M NaCl in the buffer solution yielding the highest coverage
density. The glass substrates immobilized with non-aggregated SERS-active Ag nanoparticles
exhibited in-situ detection sensitivity of Rh6G at sub-ppt level, even under highly acidic or basic
conditions. The SERS-active substrates could be regenerated by removing the adsorbed Rh6G in
a dilute hydrogen-peroxide solution. The effect of salt addition in the analyte solution on the
SERS activity of the glass substrates will be discussed.
04-03
The Growing Usage and Importance of Near Infrared Technology
AMANDA UPTON, Clarkson University, Potsdam, NY
The recent research involving the use of Near Infrared (NIR) has shown to be valuable to the
university. NIR is a close resemblance of Infrared (IR) because of its’ ability to pick out
functional groups that are contained within a substance. This is a fairly new spectroscopic
technique that has been able to improve upon the current way an IR sample can be taken. This is
a time efficient and a non-destructive way of analyzing substances of all sorts. NIR has many
practical applications in numerous analytical fields including both pharmaceutical and forensics.
These fields are able to use NIR technology to build a library containing various samples in order
to perform both qualitative and quantitative analysis. Once the library has been built, it becomes
possible to use new samples and compare them to the library that has been created to determine
if the sample meets the company’s needs.
NANOPARTICLES,
CONSUMER PRODUCTS
COLLOIDS
AND
INTERFACES
IN
P5-01
Smart Plant Protein Inside Microdevices
AMY SHEN1, William Pickard1, Michael Knoblauch2, Winfried Peters1, 1Department of
Mechanical and Aerospace Engineering, Washington University, St. Louis, MO, 2Fraunhofer
Institute for Molecular Biology and Applied Ecology, Germany, aqshen@me.wustl.edu
With the discovery of the plant protein forisome, a novel, smart non-living, ATP-independent
biological material became available to the designer of smart materials for advanced actuating
and sensing. The in vitro studies show that forisomes (1-3 micron wide and 10-30 micron long)
can be repeatedly stimulated to contract and expand anisotropically by shifting either the ambient
pH or the ambient calcium ion concentration. We probe the forisome's conformation change
inside a microfluidic device with the pH modulation. We demonstrate that the surface properties
of the channel wall and the flow condition can influence the anisotropic shape change of
forisomes, and their actuation kinetics significantly. This study provides insights for
multifunctional microvalve fabrication.
P5-02
The Synthesis of Polyvinylamine Microgels and Their Effect on Paper Strength
CHUANWEI MIAO, Robert Pelton, McMaster Centre for Pulp and Paper Research, Department
of Chemical Engineering, McMaster University, Hamilton, ON, Canada, peltonrh@mcmaster.ca
Polyvinylamine (PVAm) microgels were synthesized by post-polymerization crosslinking. In
this method, linear PVAm aqueous solution was induced to separate phase by adding salt and
adjusting pH, followed by the addition of glutaraldehyde which reacted with amine groups on
PVAm chains to crosslink the formed polymer aggregations. Three PVAm microgel samples
with different mean size were prepared and their contributions to paper strength were tested and
the results were compared with those of linear PVAm. Handsheets containing these polymers
were made and their dry tensile, wet tensile and internal bond strengths were measured. The
results demonstrated that PVAm microgels can improve strength compared to linear PVAm
when the polymer dosage is higher than 0.2 wt % based on the weight of dry pulp. The size of
microgels does not have significant effect. Two mechanisms of the better performance of
microgels were postulated. Firstly, microgels can achieve higher retention due to their bulk
volume; secondly, the deformation of microgels during drying process can fill the voids between
rough fibre surfaces to increase the bonding area.
P5-03
Effect of Porosity and Carbazole Concentration on the Reflective Electrochromic Display
Prepared by Monodisperse Carbazole-Modified Polymeric Microspheres
JUNG-HUN LEE, Jee-Hyun Ryu, Kyung-Do Suh, Division of Chemical Engineering, College of
Engineering, Hanyang University, Seoul, Republic of Korea, kdsuh@hanyang.ac.kr
Polycarbazole and its copolymer are the well-known electrochromic materials, which show a
dark green color at the applied potential. Reflective electrochromic display (R-ECD) based on
polymeric microspheres containing carbazoyl pendants were prepared using the seeded swelling
and polymerization method, then synthesized bicarbazole were refluxed with the chlorofunctional groups. The porosity and content of carbazole groups were diversified by controlling
the amount of toluene and chloropropene in the 2nd monomer mixture, respectively. Response
time of R-ECD was considerably affected by the specific surface area of microspheres, and the
concentration of carbazole incorporated. The swelling procedure and morphology of polymeric
microspheres were monitored utilizing an optical microscopy and SEM, respectively.
Reflectance changes were measured by spectrophotometer. Response time and color efficiency
of R-ECD were measured by electro-optic spectrometer.
P5-04
Novel Use of Surfactants in Copper Chemical Mechanical Polishing
YOUNGKI HONG, Udaya B. Patri, Suresh Ramakrishnan, and S.V. Babu, Interdisciplinary
Engineering Science, Department of Chemical Engineering, Center for Advanced Materials
Processing, Clarkson University, Potsdam, NY, hongy@clarkson.edu
Surfactants have been used as one of the components of CMP slurries to mainly stabilize the
slurries. However, ionic surfactants can interact with material surfaces and change the property
of its surface. In this study, Sodium Dodecyl Sulfate (SDS), one of the conventional anionic
surfactants was examined as an inhibiting agent of copper dissolution in chemical mechanical
planarization (CMP) slurry. SDS showed superior performance on the inhibition of copper
dissolution to Benzotriazole (BTA) at acidic condition. SDS of 1mM effectively shut downed the
dissolution of copper film as low as ~0nm/min. and the loss of polishing rate was comparable to
that of BTA in the case of typical slurry system of glycine and hydrogen peroxide. According to
the contact angle measurement result that can determine the hydrophilicity of material surface,
SDS turned the hydrophilic surface of copper film into hydrophobic.
SDS and a positively charged copper-film surface at acidic and neutral pHs (IEP = 9~10)
develop electrostatic attraction between them. This electrostatic attraction could introduce a
surfactant layer onto the copper-film surface and develop a hydrophobic layer of surfactant. This
hydrophobic layer could protect the copper-film surface from the slurry chemicals that could
dissolve the copper surface. And this hydrophobic layer can be removed by the physical forces.
So this aspect can maximize the planarization efficiency of copper CMP and minimize the
dishing of copper wire.
P5-05
Selective Polysilicon Chemical-Mechanical Planarization (CMP) during Fabrication of
Micro-Electro-Mechanical-Systems (MEMS) Devices using Surface-Modified Aabrasives
ANITA NATARAJAN1, Sharath Hegde1, S. V. Babu1, 2, 1Department of Chemical Engineering,
2
Center for Advanced Materials Processing, Clarkson University, Potsdam, NY
An important step in micro-electro-mechanical system (MEMS) device fabrication is deposition
and etching of few microns thick layers of polysilicon and silicon dioxide. To minimize the
processing difficulties in subsequent processes like patterning, deposition and etching, it is
desirable to planarize each deposited polysilicon layer using CMP. In one of the several
polishing steps during the device fabrication sequence, selective polishing of the polysilicon top
layer over the underlying silicon dioxide/nitride layer is required. Hence, a polishing slurry that
selectively removes polysilicon over underlying silicon dioxide or silicon nitride is critical to
prevent erosion of either silicon dioxide/nitride, which would be detrimental to the subsequent
fabrication steps.
Colloidal silica (~50nm) and calcined ceria (~250 nm) based slurries were used to achieve high
polysilicon polish rates (250-500 nm/min) and high selectivity of polysilicon over silicon dioxide
and silicon nitride (> 75:1). The surface characteristics of the abrasive and wafer surface were
modified in the presence of several additives. The additive role in the suppression of silicon
dioxide and silicon nitride removal rates by adsorption to the abrasive and wafer surface was
confirmed through Fourier transform infra- red (FTIR) spectroscopy and zeta potential
measurements.
P5-06
Role of Complexing/Chelating Agents in Copper CMP Slurries
U. B. PATRI, S. Pandija, S. V. Babu, Center for Advanced Materials Processing and Department
of Chemical Engineering, Clarkson University, Potsdam, NY
Typically copper CMP slurries are composed of an oxidizer, the most preferred one being
hydrogen peroxide (H2O2), a corrosion inhibitor like benzotriazole (BTA), a
complexing/chelating agent and other additives along with abrasives like silica or alumina.
Glycine, citric acid, ethylene diamine, ethylene diamine tetra acetic acid are some of the many
complexing/chelating agents that have been investigated in Cu CMP slurries. However, there has
been no definitive elucidation of the role of the molecular structure of the complexing agents different functional groups (eg: -NH2 vs. -COOH), their relative positions, the length of the
carbon chain, etc., - in interacting with copper surface and controlling the material removal rates.
In this study, several complexing agents containing amine and/or carboxyl groups (acetic acid,
succinic acid, ethylene diamine, glycine, alanine, amino butyric acid and others) have been
studied to understand better the role of the molecular structure in determining copper removal
rates. The results are consistent with the known activity of –COOH groups at acidic conditions
and that of –NH2 groups in an alkaline environment. In comparison with glycine, it was also
observed that an increase in the carbon chain length increased the removal rates at acidic pH
values and decreased the removal rates at alkaline pH values. Also, Cu removal rates decreased
with an increase in the distance between the –NH2 and –COOH groups in an amino acid at all pH
values except at 4.
P5-07
Influence of Particle Surface Charge with Charged Oxidizing Agents for Cu CMP
KENNETH RUSHING, Yuzhuo Li, Department of Chemistry and Center for Advanced
Materials Processing, Clarkson University, Potsdam, NY, yuzhuoli@clarkson.edu
Hydrogen peroxide has played a vital role in many of the copper CMP systems involved in the
manufacturing of IC chips. Recent studies on the use of hydrogen peroxide have suggested
mechanisms for the formation of hydroxyl radicals (*OH) as the key component in modifying
the copper surface. These hydroxyl radicals are highly reactive intermediates bearing no formal
charge leading to very little or no interaction among the charged abrasive particles within a CMP
slurry.
Substituting potassium persulfate for hydrogen peroxide in a traditional system has shown
promise in the removal and planarization of the overburden copper. Knowledge of potassium
persulfate suggests a mechanism, through single-electron transfer and the presence of water, in
which there is a production of sulfate radical anions and hydroxyl radicals. These sulfate radical
anions carry a formal charge of -1 allowing for interaction among charged abrasive species.
This presentation will demonstrate how the charge of a particle will influence the removal and
planarization of copper using anionic oxidizing agents. The particles being studied will possess
no surface charge, negative surface charge or positive surface charge within the aqueous slurry.
P5-08
Effect of total surface area of solids on material removal rate in metal polishing
S. RAMAKRISHNAN, S. B. Janjam, E. Matijević, S. V. Babu, Chemical Engineering
department and Center for Advanced Materials Processing, Clarkson University, Potsdam, NY,
ramaksur@clarkson.edu
The properties of abrasive particles play a significant role in chemical mechanical planarization
(CMP) of metal films. The effect of particle size (silica) on the material removal rates of copper
and tantalum in hydrogen peroxide based slurries containing glycine as a complexing agent was
investigated earliera. It was shown that the total surface area of the solids in the slurry controlled
the material removal rates for both Cu and Ta. The present work extends these studies to other
complexing agents: citric acid, maleic acid and acetic acid.
P5-09
Role of Oxalic acid in Slurry for Copper CMP
S. PANDIJA, D. Roy, S. V. Babu, Department of Chemical Engineering and Center for
Advanced Materials Processing, Clarkson University, Potsdam, NY, pandijas@clarkson.edu
Copper (Cu) disks were polished using oxalic acid and H2O2, with and without abrasives (3 wt %
colloidal silica – 50 nm), at different values of the solution pH. Cu polish rates with and without
abrasives were similar, indicating that oxalic acid is an effective complexing agent in abrasivefree slurries. At pH ~ 1.5, dissolution rates of Cu in slurry containing oxalic acid and H 2O2 were
low and the rates increase with an increase in the pH till pH = 3.0. A similar trend was observed
with the polish rates of Cu. At pH = 3.0, when the concentration of H2O2 was increased from 0
wt % to 5 wt % in the slurry, the dissolution rates increased, becoming almost constant thereafter
till 8 wt % H2O2 and then decrease with a continued increase in the H2O2 concentration.
Electrochemical and UV/Visible spectroscopic measurements were performed in order to
understand the observed trends of Cu polish rates and formation of Cu-oxalic acid complex.
NANOPARTICLES, COLLOIDS AND INTERFACES IN MEDICAL/BIOMEDICAL
DIAGNOSTIC APPLICATIONS
P6-01
Controlled Release of Plasmid DNA from Gold Nanorods Irradiated by Pulsed NearInfrared Light
H. TAKAHASHI, Y. Niidome, T. Niidome, S. Yamada, Department of Materials Physics and
Chemistry, Graduate School of Engineering, Kyushu University, Hakozaki 6-10-1, Higashi-ku,
Fukuoka, Japan, thirotcm@mbox.nc.kyushu-u.ac.jp
Gold nanorods (NRs) are rod-like nanoparticles that have unique optical properties depending on
their shape. In order to use NRs for biochemical applications, we have first partially modified
them with phosphatidylcholine (PC). Partial modification of NRs with PC has been successful
by extraction with chloroform containing PC. The resultant PC-modified NRs (PC-NRs) could
form complexes with plasmid DNA by electrostatic interactions, denoted as PC-NR/DNA.
Pulsed laser irradiation of NRs induces shape changes into spherical nanoparticles. Irradiation of
pulsed 1064-nm laser light (250 mJ/pulse, 2 min) to PC-NR/DNA complexes induced shape
changes of PC-NRs and at the same time plasmid DNA were released from the complexes as
confirmed from gel electrophoresis. Thus, it is clear that the shape changes of PC-NRs trigger
the release of DNA from the complexes. It was also found that the plasmid DNA was released
without any damage by laser irradiation. Thus, the near-IR laser irradiation onto the PCNR/DNA complexes has realized the selective release of the plasmid DNA without appreciable
structural changes.
P6-02
Preparation and Characterization of Genistein-Modified PLGA Nanocapsules by
Introducing the Cationic Moiety
JEONG-BEOM NAM1, Jee-Hyun Ryu1, Jin-woong Kim2, Kyung-Do Suh1, 1Division of
Chemical Engineering, College of Engineering, Hanyang University, Seoul, Republic of Korea,
2
Div. of Engineering & Applied Sciences, Harvard University, Cambridge, MA,
kdsuh@hanyang.ac.kr
Nanocapsules, which formulated from the biodegradable polymers such as poly(D,L-lactide-coglycoide) (PLGA), poly(D,L-lactide) (PLA), are being extensively investigated as drug release
vehicle, or specific carriers for gene delivery. Genistein, extracted from soybeans, is one of the
good anti-oxidant agents, therefore, it was chosen a model drug in this study. A cationic moiety,
amine structure, was incorporated to the PLGA to capsulate the genistein more efficiently. The
modified PLGA-genistein nanocapsules were prepared by using a emulsion-evaporation method.
At first, the modified PLGA and genistein in acetone solvent were poured into the Tween 60
aqueous solution with a mechanical stirring. Encapsulation of genistein was achieved by means
of the ionic interaction between anionic hydroxyl groups of genistein and cationic amine groups
of modified PLGA in the micelles. The content of genistein in nanocapsules and antioxidant
activity of capsules were examined utilizing an high performance liquid chromatograph (HPLC)
and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method, respectively. Depending
on the concentration of cationic moiety in the modified PLGA, the in vitro release profiles of
genistein was also investigated.
P6-03
Patterns of the Salt Effects on Protein-Protein Interactions and Their Implications for
Protein Crystallization
A. C. DUMETZ, E. W. Kaler, A. M. Lenhoff, Department of Chemical Engineering, University
of Delaware, Newark, DE, dumetz@che.udel.edu
Proteins have a typical size of few nanometers, and so are in the lower range of the colloidal
domain. In order to map out the main patterns of protein-protein interactions, the second osmotic
virial coefficient (B22) has been measured using self interaction chromatography (SIC) for seven
different proteins (ovalbumin, ribonuclease A, myoglobin, α-lactalbumin, BSA, catalase,
cytochrome C) under different conditions of salt and pH. At low salt concentrations the protein
interactions can be either attractive or repulsive. At higher salt concentrations, when electrostatic
interactions are completely screened, the trends depend of the type of salt. In sodium chloride,
for all the proteins studied the B22 remains unaffected, whereas in ammonium sulfate B22 drops
steeply at different salt concentrations for each protein. These last trends emphasize the
importance of non-DLVO forces on protein interactions and are mainly interpreted in terms of an
hydration effect.
NANOPARTICLES, COLLOIDS AND INTERFACES IN MEDICAL/BIOMEDICAL
DIAGNOSTIC APPLICATIONS
P7-01
Thermodynamic Study of the Effects of Procaine on Phospholipid Monolayers
M. TOMOAIA-COTISEL1, A. Mocanu1, P.T. Frangopol1, D. A. Cadenhead2, 1 “Babes-Bolyai”
University of Cluj-Napoca, Physical Chemistry and Biophysics Department, 3400 Cluj-Napoca,
Romania, and 2State University of New York at Buffalo, NY, mcotisel@yahoo.com
The influence of the local anesthetic procaine (PR) on 1,2 – dipalmitolyl-sn-glycero-3phosphocholine (DPPC) monolayers was investigated at the air/water interface by Langmuir
technique. Compression isotherms were investigated as function of concentrations of procaine
hydrochloride in aqueous solutions in the range from 10-6 to 10-2 M. The amount of PR
penetrating into the DPPC monolayers was derived from the surface pressure increase with
increasing procaine concentrations recorded at constant molecular area of DPPC by using the
Gibbs’ adsorption equation adapted to interfacial penetration phenomena. The findings show that
the presence of DPPC monolayers produces an enhanced adsorption of PR at the air/water
interface. At the monolayer collapse an exclusion of PR molecules from the DPPC monolayers is
evidenced by atomic force microscope observations on Langmuir-Blodgett films transferred on
solid substrates. The pressure dependence of the penetration of the local anesthetic procaine into
the phospholipid monolayers may be of relevance in the phenomenon of pressure reversal in
anesthesia.
NANOPARTICLES, COLLOIDS AND INTERFACES IN THE ENVIRONMENT
P8-01
Colloid Retention and Transport in Porous Media with Mixed Wettability
JIE HAN, Yan Jin, Department of Plant and Soil Sciences, University of Delaware, Newark, DE
Migration of colloids can facilitate transport of bacteria, virus, metal, and radionuclide in the
subsurface environment. In this study, saturated and unsaturated column experiments were
conducted to examine the behavior of latex particles with diameter of 19 nm in 300 to 355 m
sand with mixed wettability using buffer solution with a constant ionic strength of 100 mM and
constant pH of 7.5. Batch experiments were conducted with hydrophilic sand, hydrophobic sand
and the mixture of them. The initial colloid concentrations were 1, 2, 5, 10, 20, 50 and 100 mg/L.
Air was completely eliminated from all tubes in order to avoid colloid attachment at the air-water
interface and examine sorption of colloids onto solid surfaces only. Results from this study
suggested that there was significant retardation of latex particles breakthrough in the presence of
hydrophobic sand and it became more significant as the fraction of hydrophobic sand increased.
Strong partitioning of colloids onto the hydrophobic surface was likely the main mechanism
contributing to the delay. Colloids behaved differently between homogeneous hydrophilic media
and mixed media under unsaturated conditions, which was attributed to the different water flow
paths.
P8-02
Design Criteria for Laboratory Reactors Used to Evaluate the Deposition of Colloidal
Particulates on the Surface of Steady State Aerobic Biological Films of Any Thickness
J. P. BOLTZ,1, E. J. La Motta,2, 1CH2M HILL, Inc., Montgomery, AL, 2University of New
Orleans, New Orleans, LA, , jboltz@ch2m.com
Generally, a substantial effort is put forth in the design of a bench-scale experimental apparatus
when evaluating fixed-film biological wastewater treatment systems.
During kinetic
investigations, steady state conditions with respect to effluent particle concentration are desirable
because they allow for the most simplistic model development and verification. The steady state
conditions in an ideal biofilm reactor include evenly distributed biofilm with constant values of
film thickness, pH, colloidal particulate concentration remaining in the effluent, DO level, and
negligible suspended growth. Realistically, these variables will fluctuate slightly. However, the
laboratory reactor must minimize this variation in order to obtain a quasi-steady state with
respect to effluent particle concentration. There is a paucity of information in the literature
detailing the design criteria for such a reactor. This presentation details the experimental setup
including: nutrient solutions necessary for film development and maintenance, commercially
available colloids (organic and inorganic), construction material, motor integration, and
sampling. Additionally, appropriate inoculation sources as they pertain to experimental
objectives are addressed. A presentation of recent research that demonstrates particle removal by
aerobic biological films is governed by a physical surface dependent process, namely
bioflocculation, indicates colloid analyses can be conducted on films of any thickness.
P8-03
Kinetic Study of Cell Proliferation of Saccharomyces cerevisiae Strains by
Sedimentation/Steric Field Flow Fractionation in Situ
J. Kapolos1, L. Farmakis2, G. Karaiskakis2, A. KOLIADIMA2, 1Department of Agricultural
Products Technology, T.E.I. of Kalamata, 24100 Kalamata, Greece, 2Department of Chemistry,
University of Patras, Patras, Greece, akoliadima@chemistry.upatras.gr
The Sedimentation/Steric Field Flow Fractionation (Sd/StFFF) technique is applied to the kinetic
study of cells proliferation of Saccharomyces cerevisiae (S. cerevisiae) strains. The size
distribution and the mass ratio of the yeast cells were determined as a function of the time from
the preparation of the yeast sample dispersion in the culture medium. The results were combined
with the growth of the yeast cells and their life cycle and compared with those obtained by
scanning electron microscopy (SEM) and those found in the literature. Useful conclusions
concerning the budding and the fission of these yeast cells were also extracted.
P8-04
Diffusion Coefficients and Partition Coefficients of SO2 in Water – Air Interface at
Different pH Values in the Presence or Absence of Surfactants.
J. Kapolos1, L. Farmakis2, G. Karaiskakis2, A. KOLIADIMA2, 1Department of Agricultural
Products Technology, T.E.I. of Kalamata, Kalamata, Greece, 2Department of Chemistry,
University of Patras, Patras, Greece, akoliadima@chemistry.upatras.gr
The physical and chemical phenomena controlling the exchange of gas pollutants between
atmospheric and water environment are of great significant in environmental chemistry.
Research in this area requires working at scales far smaller than those normally associated with
the bulk processes on either side of interface, and requires new experimental and theoretical
approaches.
In this work the relatively new technique of reversed flow gas chromatography (RF-GC) has
been applied for measuring the diffusion coefficients of one of the most common pollutant, SO2,
in water at different pH. Also their partition coefficients in water-air interface were calculated
giving information not only on phase equilibria but also on interface transport across the air –
water boundaries.
Finally the effect of surfactants (FL-70 and Triton) on the transfer of SO2 into water was studied.
P8-05
Influence of dissolved organic matter and pH on the transport of Cryptosporidium parvum
oocysts in a geochemically heterogeneous saturated porous medium
R. A. ABUDALO1, J. N. Ryan1, R.W. Harvey2, D. W. Metge2, 1University of Colorado at
Boulder, Department of Civil, Environmental, and Architectural Engineering, University of
Colorado, 428 UCB Boulder, CO, 2U.S. Geological Survey, Water Resources Division, 3215
Marine Street, Boulder, CO, rula.abudalo@colorado.edu
Dissolved organic matter (DOM) may affect the attachment of Cryptosporidium parvum oocysts
(a pathogenic protozoan pathogen) in aquifer sediments by altering the surface characteristics of
the oocysts and the grains. To test the effect of DOM on oocyst transport in geochemically
heterogeneous porous media, we measured removal of oocysts in flow-through sand columns in
the presence of a well-characterized fulvic acid (FA) from the Florida Everglades (0 to 20 mg L1
) under low pH (pH 5.6-5.8) and ionic strength (10-4 M) conditions. The columns were packed
with a mixture of quartz sand (96%) and ferric oxyhydroxide-coated quartz sand (4%).
Deposition of oocysts within the sand columns decreased with increasing FA concentration.
Collision efficiencies () decreased from 0.25 to 0.12 as the FA concentration increased. To test
the effect of pH on oocyst transport in similar geochemically heterogeneous porous media, a
second set of flow-through sand columns were conducted over a pH range of 5.7 to 10.0 at low
ionic strength (10-4 M NaCl). Results of these experiments demonstrated that the magnitude of
oocysts breakthrough was sensitive to pH; the increase in pH from 5.7 to 10.0 decreased α by
50%.
NANOPARTICLES, COLLOIDS, AND SURFACES IN ADVANCED CATALYTIC
MATERIALS
P9-01
Characterization of Ni-Zn/TiO2 nanoparticles synthesized by liquid phase selectivedeposition method
YOJI SUNAGAWA1, Katsutoshi Yamamoto2, Sarantuya Myagmarjav1, Hideyuki Takahashi2,
Kiyoshi Kanie2, Nobuaki Sato2, Atsushi Muramatsu2, 1Graduate School of Environmental
Studies, Tohoku University, Sendai, Japan, 2Institute for Multidisciplinary Research for
Advanced Materials, Tohoku University, Sendai, Japan
Liquid phase reduction method is among various methods to synthesize nanometer-size metallic
particles as catalyst. It has been reported that nickel and nickel-zinc nanoparticles synthesized by
liquid-phase reduction method had amorphous-like structure with a diameter from 5 to 10 nm.
Additionally, the catalytic activity was promoted for 1-octene hydrogenation by adding Zn to Ni
nanoparticles. However, unsupported nanoparticles lost their high catalytic activity due to
aggregation. In order to solve this problem, we have been reported that Ni nanoparticles were
selectively deposited onto support materials such as TiO2. In the present study, the addition of Zn
proved to decrease the nanoparticles size, leading to the increase in the total area of catalytically
active Ni surface. In addition, nanoparticles were highly stabilized by the deposition on TiO 2, so
that the catalytic activity of Zn-added TiO2-supported Ni nanoparticles (Ni-Zn/TiO2) in the 1octene hydrogenation was ca. 10 times higher than that of unsupported Ni nanoparticles.
NANOSTRUCTURES FOR QUANTUM DEVICE TECHNOLOGY
P10-01
Material Properties Optimization for Solid State Quantum Computing
L. Fedichkin1, A. FEDOROV1, V. Privman1 and M. Yanchenko2, 1Center for Quantum Device
Technology, Department of Physics and Department of Electrical and Computer Engineering,
Clarkson University, Potsdam, NY, 2Russian Academy of Sciences, 34, Nakhimovsky prosp.,
Moscow, Russia, fedorov@clarkson.edu
Different approaches in quantifying environmentally-induced decoherence are considered. We
identify a measure of decoherence, derived from the density matrix of the system of interest, that
quantifies the environmentally induced error, i.e., deviation from the ideal isolated-system
dynamics. This measure can be shown to have several features useful for optimization of a
particular quantum computer design which includes selection of the suitable materials and
regimes for coherent control. As a representative example, decoherence of an electron in double
quantum dot due to the interaction with acoustic phonons is considered for different
experimentally accessible materials.
P10-02
Quantum Dynamics of Electron in a Cycle of Coupled Quantum Dots
L. FEDICHKIN, D. Solenov, C. Tamon, V. Privman, Center for Quantum Device Technology,
Department of Electrical and Computer Engineering, Department of Physics and Department of
Mathematics and Computer Science, Clarkson University, Potsdam, NY, leonid@clarkson.edu
We derive the set of dynamical equations describing quantum evolution of electron in the array
of semiconductor quantum dots forming circle. In the limit of week decoherence the
asymptotically exact analytical solution of these equations is obtained. The effect of decoherence
on particle dynamics at stronger decoherence rates obtained numerically is also presented.
Results show non-trivial dependence of hitting and mixing times upon the decoherence rate.
P10-03
Loss of Coherence in a Qubit Subject to Time-Dependent Gates
D. SOLENOV, V. Privman, Center for Quantum Device Technology, Department of Physics and
Department of Electrical and Computer Engineering, Clarkson University, Potsdam, NY,
solenovd@clarkson.edu
We present the results of the investigation on decoherence processes in qubit systems
manipulated by external gates. Different types of time-dependence for the gate functions are
considered. We utilize Magnus unitarity-preserving expansion to formulate the approximation
for the evolution operator suitable to handle essentially time-dependent gates. Estimates to
decoherence of a qubit controlled by the external rotating wave are obtained.
P10-04
Decoherence and Loss of Entanglement
D. TOLKUNOV, V. Privman, Center for Quantum Device Technology, Department of Physics,
Clarkson University, Potsdam, NY, tolkunov@clarkson.edu
We review our recent work establishing by an explicit many-body calculation for an open
quantum-mechanical system of two qubits subject to independent noise modeled by bosonic
baths, a new connection between two important issues in the studies of entanglement and
decoherence. We demonstrate that the decay of entanglement is governed by the product of the
suppression factors describing decoherence of the subsystems (qubits). This result is the first
detailed model calculation proving an important and intuitively natural physical property that
separated open quantum systems can evolve coherently, quantum mechanically on time scales
larger than the times for which they remain entangled.
Our result also suggests avenues for future work. Specifically, for multiqubit systems, it is
expected that similar arguments should apply “by induction.” This will stimulate research to
develop appropriate quantitative measures of entanglement, and attempts to quantify
entanglement and decoherence in a unified way.
P10-05
Qubit Decoherence due to Interaction with Non-Ideal Phonon Bath.
S. SAIKIN1,2, V. Privman1, 1Center for Quantum Device Technology, Department of Physics
and Department of Electrical and Computer Engineering, Clarkson University, Potsdam, NY,
2
Department of Physics, Kazan State University, Kazan, Russia, saikin@clarkson.edu
Most recent studies of non-markovian evolution of a two-level quantum system due to
interaction with a bath are based on a spin-boson model, where a thermal bath is represented by a
set of non-interacting oscillators. However, in realistic systems the later assumption of noninteracting modes of a bath is not valid. We study how internal dynamics of a phonon bath due to
phonon-phonon interactions and isotope scattering affects irreversible evolution of a qubit.
P10-06
Monte Carlo Simulation of Spin-polarized Injection in a Schottky Diode
M. SHEN, S. Saikin, M.-C. Cheng, V. Privman, Center for Quantum Device Technology,
Department of Physics and Department of Electrical and Computer Engineering, Clarkson
University, Potsdam, NY, shenm@clarkson.edu
Spin-polarized injection in an Fe(100)/GaAs(100) Schottky diode is investigated by Monte Carlo
simulation approach. Scattering mechanisms of both intra-valley and inter-valley are considered.
Spin dynamics in the Γ and L valleys are taken into account in the model. The simulation shows
that the upper (L) valleys have significant influence to spin transport close to the Schottky
barrier. The simulation results are in good agreement with experimental data.
P10-07
RKKY Interaction in 1D Electron Systems
ALEX DEMENTSOV, Dima Mozyrsky, Denis Tolkunov, Center for Quantum Device
Technology, Department of Physics, Clarkson University, Potsdam, NY
The indirect interaction between localized spins in 1D electron systems is considered within the
frameworks of Luttinger model. It is shown that interaction between conduction electrons
serving as carriers of indirect interaction between localized spins plays a significant role.
PREPARATION AND APPLICATIONS OF SOFT COLLOIDS
MICROEMULSIONS, EMULSIONS AND RELATED SYSTEMS)
(MICELLES,
P11-01
Thermodynamic Approach on Specific Interactions in Mixed Lipid and Carotenoid
Monolayers
A. MOCANU1, G. Tomoaia2, Cs. Racz1, M. Tomoaia-Cotisel1, 1“Babes-Bolyai” University of
Cluj-Napoca, Department of Physical Chemistry and Biophysics, and 2”Iuliu Hatieganu”
University of Medicine, Department of Orthopaedic Surgery, 3400 Cluj-Napoca, Romania,
amocanu@chem.ubbcluj.ro
Mixed lipid and carotenoid monolayers spread at the air/water interface, namely (1) egg lecithin :
β-cryptoxanthin; (2) egg lecithin : β-cryptoxanthin palmitate; (3) egg lecithin : zeaxanthin
monopalmitate; (4) distearoyl lecithin : zeaxanthin; (5) distearoyl lecithin : astaxanthin; and (6)
distearoyl digalactosyl glycerol : astaxanthin have been investigated. The curves of surface
collapse pressure versus monolayer composition are discussed in terms of surface mixture
thermodynamics. It has been found that the system (1) presents a perfect behaviour throughout
the entire range of composition, while systems (2) and (3) can be satisfactorily described by the
regular solution theory. For systems (4) - (6) a new approximation is proposed, considering the
formation of supramolecular associations in monolayers. The stability constants of the
supramolecular complexes in monolayers are calculated and correlated to the specific
interactions that can occur in these mixed monolayers in substantial agreement with the
molecular structures of the investigated biocompounds.
P11-02
Formation of Nanolatices within Phase Segregated Micelles
S. ROGERS, J. Eastoe, School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
United Kingdom, sarah.rogers@bristol.ac.uk
The growth of polymer nano-lattices in novel microemulsions has been studied. The systems
used exploited the natural incompatibility of fluorocarbon and hydrocarbon materials to drive
local phase segregation inside the microemulsion droplets. This was achieved by using a matrix
of systems comprising of fluorocarbon and hydrocarbon surfactants and monomers.
Both thermal and UV initiated polymerizations have been carried out and the effect this has on
the final lattices studied. These polymerizations have been followed via 1H NMR and
SANS/SAXS and the final products imaged via TEM. Results will be reviewed and future
prospects presented.
P11-03
Thermal and Rheological Properties of Carbon nanotube-in-oil Dispersions
YING YANG1, George Z. Zhang2, Eric Grulke1, Gefei Wu2 , 1Department of Chemical and
Materials Engineering, University of Kentucky, Lexington, KY, 2The Valvoline Company, P.O.
Box 14000, Lexington, KY, yyang7@uky.edu
Prior work on asymmetric thermally conducting nanoparticles in dispersions with low thermal
conductivity liquids has shown that it is possible to tailor fluids with higher thermal
conductivities than the base fluid at modest volume fractions of nanoparticles. Stable and
reproducible nanotubes dispersions require careful control of the dispersant chemistry as well as
an understanding of their response to shear and temperature changes. This paper addresses the
effects of dispersant concentration, energy per unit volume for dispersion, and nanoparticle
loading on thermal conductivity and steady shear viscosity of nanotube in oil nanofluids. The
thermal conductivities and viscosities of these dispersion correlate to each other, and vary with
the size of large scale agglomerates, or clustered nanoparticles, in the fluids. Fluids with large
scale agglomerates have high thermal conductivities. Dispersion energy such as sonication can
decrease agglomerate size, but also breaks the nanotubes, decreasing both the thermal
conductivity and viscosity of nanofluids. Developing high thermal conductivity nanoparticle
dispersions may require a balance between the high thermal conductivity of agglomerate
structures and the high viscosity of these fluids.
P11-04
Selective Aggregation of Morin in Different TritonX-100 micelles
Weiya
Liu,
Rong
Guo,
Yangzhou,
University,
Yangzhou, Suzhou, P. R. China, liuweiya@hotmail.com
27
Wenhua
Rd.,
Morin (3,2’,4’,5,7-pentahydroxyflavone) is one of the effective antioxidant substances from
natural plants and vegetables which can occur dimerization in the solution. The interaction
between morin and the TritonX-100 micelles are studied by electronic absorption, fluorescence
emission, ATR-FTIR spectra, FF-TEM (Freeze-fracture TEM), and the ab initio quantum
calculation. Some interesting results are found.
Morin can be solubilized in the TritonX-100 spherical micelle mainly in the form of the dimer
and the hydrophobic force is the main driving force. The morphology of the micelle is changed
from spherical to rock-like and the size of the single spherical micelle is increased with the
solubilization of the morin. Morin cannot be located inside the TritonX-100 rod-like micelles
because of the compact structure and limited solubilization space of the rod-like micelles, but
morin can exist in the form of the monomer and link the rod-like micelle by forming H-bonding
with TritonX-100 to form a kind of network structure. The ab initio quantum chemical
calculations of morin show that the stable structure of morin is not planar with the phenyl (Bring) connected to the C-ring by a single C-C bond around which rotation can occur, and the Bring deviates with 38.98 o from the planarity. No matter morin interacts with TritonX-100 micelle
in the form of monomer or dimer, the active site involves in the interaction is always the phenyl
group in the molecule, which leads to the limitation of the rotation of B-ring and the increased
planarity of the whole morin molecule. The structure of morin dimer is determined by the
nanoscale solubilization space of the spherical TritonX-100micelle.The two B-rings (deviating
with 38.98 o from the planarity of the morin molecule) are linked by the H-bonding in a face to
face mode making the two morin molecules pile up into dimer and the two piled up phenyls are
whole located in the TritonX-100 spherical micelle.
RHEOLOGY AND DYNAMICS OF COMPLEX FLUIDS
P12-01
Evaluating the Intrinsic Bending Force in Chiral Bilayer Membranes by Molecular
Dynamics Simulations
N. GOUTEV, Shimizu, CREST, Japan Science and Technology Agency, Nanoarchitectonics
Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba
Central 4-4, 1-1-1 Higashi, Tsukuba, Ibaraki, Japan, nikolay.v.goutev@aist.go.jp
Bilayer membranes made of certain lipids can form twisted or helical ribbons as well as tubules
with chiral molecular packing. According to a current continuum elasticity theory, such chiral
supramolecular structures originate from an intrinsic bending force that appears in bilayer
membranes with broken chiral symmetry. All variants of the continuum theory developed so far
start by assuming a functional for the elastic energy of the bilayer membranes and end up
expressing the optimal dimensions of the supramolecular structures in terms of several elasticity
moduli. On the example of two glucolipids, which form tubules and twisted ribbons,
respectively, we show here that instead of being assumed the relevant functional and elasticity
moduli can be derived by molecular dynamics simulations of model bilayer membranes with an
all-atom force field like CHARMM. The results of the simulations support directly the concept
of an intrinsic bending force in chiral bilayer membranes.
P12-02
Atomic Force Microscopy Studies of Langmuir-Blodgett Films: Phase Transitions in
Phospholipid Monolayers
G. Tomoaia1, M. Tomoaia-Cotisel2, A. Mocanu2, C.-R. ISPAS2, A. Dumitru2,I. Halaciuga3,
1
”Iuliu Hatieganu” University of Medicine, Orthopedic Surgery, and “Babeş-Bolyai” University
of Cluj-Napoca, 2Physical Chemistry and Biophysics Department and 3Physics Department, 3400
Cluj-Napoca, Romania, cispas@chem.ubbcluj.ro
Phase behavior and surface structure of dipalmitoyl phosphatidyl choline (DPPC) spread as
Langmuir monolayers at the air/water interface in the absence and in the presence of two drugs
in the aqueous phase, such as procaine (PR) or deferoxamine (DFO), at a drug concentration of
10-3 and 10-6 mole dm-3, respectively, have been investigated using Langmuir-Blodgett (LB)
technique and atomic force microscopy (AFM). The LB films were transferred on solid
substrates, like glass optically polished and mica, at different controlled surface pressures by
using vertical transfer and horizontal deposition method. Depending on the lateral surface
pressure, highly ordered structures and less organized features have been directly evidenced. In
addition these observations reveal some specific molecular interactions between these
biologically relevant biocompounds. The data also indicate that both procaine and deferoxamine
can penetrate and interact with phospholipid monolayers stabilizing the membrane lipids at both
internal and external membrane interfaces.
P12-03
The Rheology and Shear-Induced Microstructure of Nanoaggregate, Fumed Silica
Dispersions
C. H. NAM, J. Wagner, Department of Chemical Engineering, University of Delaware, Newark,
DE, wagnernj@udel.edu
The rheology of polymeric suspensions of fumed silica particles of varying volume fraction,
sizes, and surface modifications are examined. Fumed silica particles are often described as
aggregated, fractal-like structures. These fractal aggregate suspensions shear thicken at much
lower particle loadings than suspensions of hard, spherical particles. For example, discontinuous
shear thickening was observed for a suspension (fumed silica in polyethylene glycol) with a
particle loading of only 7% by vol. In this work we explore the mechanism and underlying
structure of fumed silica particle dispersions by rheology, microscopy, and light scattering.
Thixotropy of the suspensions is also explored with rheological experiments. The results are
compared to previous results for shear thickening in near hard sphere suspensions.
P12-04
Numerical Simulation of Particle-Surface Interaction in a Turbulent Channel Flow
H. NASR1, M.D. Emami2, Ahmadi1, 1Department of Mechanical and Aeronautical Engineering,
Clarkson University, Potsdam, NY, 2Department of Mechanical Engineering, Isfahan University
of Technology, Isfahan, Iran
This study presents a computational model for Lagrangian simulation of particle transport,
dispersion, and deposition including the possibility of rebound from the wall in a turbulent
channel flow. An empirical mean velocity profile for the fluid velocity and experimental data for
turbulent intensities are used in the analysis. The instantaneous fluctuating velocities are
simulated by a continuous Gaussian random field model. The particle equation of motion takes
into account the Stokes drag, the Saffman lift, the Brownian motion, and the gravitational forces.
The Brownian diffusion is simulated as a white noise process. Starting with an initially uniform
concentration near the wall, an ensemble of particle trajectories is generated and statistically
analyzed. Several simulations for deposition of aerosol particles of various sizes are performed
and the corresponding deposition velocities are evaluated. The computational model predictions
for particle deposition velocity are compared with the existing experimental data and earlier
simulation results and favorable agreements are observed.
P12-05
Gas-Liquid Dynamic Behavior in a Bubble Column Reactor
W. CHEN, G. Ahmadi, Department of Mechanical and Aeronautical Engineering, Clarkson
University, Potsdam NY, chenw@clarkson.edu
Bubble coalescence and breakup-up are important processes that control the bubble size
distribution in bubble column reactors. An experimental and computational study of the effect of
gas superficial velocity on the bubble size distribution in a (200×10×1000 mm3) rectangular
bubble column was performed. Bubble size distributions were measured using a high speed
digital CCD camera and analyzed by LabVIEW image process system. Dispersed gas-liquid
flow in bubble column was simulated by a population balance model Eulerian multiphase flow
approach within the FLUENT code. The mechanisms of bubble breakup by the turbulence eddy
and bubble coalescence were included in the analysis. It is seen that a central wave-like bubble
plume appears with two staggered rows of vortices which control the roughly chaotic oscillation
characteristics of the bubble column. The relations between the bubble size distributions in
horizontal and vertical direction were studied. The model predictions were found to agree well
with the experimental data.
P12-06
The Use of Spin-Echo NMR Experiments for the Investigation of the Dynamics in a Model
Slurry System for CMP Containing Silica Particles
FADWA ODEH, Yuzhuo Li, Department of Chemistry, Clarkson University, Potsdam, NY,
odehfm@clarkson.edu
With continuous increase in the complexity of current microelectronic devices and integration of
Cu as interconnect, it is required that CMP provides a good surface planarity with minimal
surface defectivity. One of the prominent roles of the abrasive particles is its ability to interact
with chemical components found in the slurry. Surface adsorption of chemical components on to
the abrasive particles can alter the intended chemical and mechanical balance of the slurry.
Slurries consisting of abrasive particles of similar characteristics but different surface adsorption
characteristic may perform differently in a CMP process. Furthermore, the introduction of copper
ions during copper CMP may exacerbate the complexity. These copper ions could interact with
the chemical components in the slurry to form copper complexes and also could change the
adsorption characteristic of the abrasive particles. The formation of the copper complex and the
change in the adsorption characteristic of the particles could have a great impact on the copper
CMP performance. Performance will be exemplified with silica based slurry.
The longitudinal relaxation times (T1) of the different components of CMP slurries were
measured using Spin Echo-NMR (SE-NMR) at a constant temperature. The fact that NMR is
non-invasive and gives information on the molecular level gives more advantage to the
technique. The model CMP slurry was prepared in D2O to enable monitoring of T1 for the
various components' protons. SE-NMR provide a very powerful tool to study the various
interactions and adsorption processes that take place in a model CMP silica based slurry which
contains BTA and/or glycine and/or Cu+2 ions, it was found that BTA is very competitive
towards complexation with Cu+2 ions and BTA-Cu complex adsorbs on silica surface.
P12-06
Competitive surface adsorption of key chemicals on abrasive particles in copper CMP
slurry
SURESH KUMAR GOVINDASWAMY1, Fadwa Odeh2, Sameer Dhane2, Yuzhuo Li2,
1
Department of Chemical Engineering, 2Department of Chemistry andCenter for Advanced
Material Processing, Clarkson University, Potsdam, NY
Chemical mechanical planarization (CMP) is an enabling technology for the production of
advanced semiconductor devices. It is used for producing global planar semiconductor wafer
surface. One of the important constituent of CMP process is the CMP slurry. Slurry is a
heterogeneous system consists of solid abrasive particles and reactive chemicals. Choosing
appropriate slurry for the process will yield a better Cu CMP performance with less defects and
high yield. To achieve this, it is important to understand the interactions among various
components in the slurry. One of the prominent roles of the abrasive particles is its ability to
interact with key chemical components found in the slurry due to its high surface area. During
the CMP process the chemical components in the slurry undergo surface adsorption onto the
abrasive particles. Surface adsorption of chemical components on to the abrasive particles can
alter the intended chemical and mechanical balance of the slurry. It is equally critical to realize
that such a surface adsorption characteristic is unique to each type of particles and the chemical
profile of the surface. Slurries consisting of abrasive particles of similar characteristics but
different surface adsorption characteristic perform differently in a CMP process. The difference
in the surface adsorption characteristic between the abrasive particles results in variation in the
interaction between the particles and the chemical constituent in the slurry.
In this talk, competitive surface adsorption of key chemicals on abrasive particles in copper CMP
slurry will be discussed. The experimental techniques used in this study will be described.
Some potential implications and applications will be discussed.
P12-07
A New Passivating System for Copper CMP
Yuzhuo Li1,2, Junzi Zhao1,2, DEENESH BUNDI2,3, KRISHNAYYA CHEEMALPATI2,3,
VIVEK DUVVURU2,3, 1Department of Chemistry, 2Center for Advanced Materials Processing
(CAMP), 3Dept of Mechanical & Aeronautical Engineering, Clarkson University, Potsdam, NY,
bundidk@clarkson.edu, cheemalk@clarkson.edu, duvvurvr@clarkson.edu
In today’s slurry for Chemical Mechanical Polishing (CMP) of copper interconnect during wafer
processing for advanced microelectronic manufacturing, the commonly used passivating
mechanism is based on the formation of a thin layer of water insoluble copper complex. The low
solubility of such a complex film prevents the dissolution of copper which protects the lower
lying area from chemical attack. One of the most commonly used compounds for such a purpose
is benzotriazole (BTA). Although BTA has been widely used in commercially available CMP
slurries and other corrosion prevention formulations, it also yielded many challenges such as post
CMP clean, over sized particle formation during CMP, and batch to batch consistency.
This poster presents a study in which an alternative mechanism for passivating metal surface is
suggested. More specifically, a surfactant system was used to replace molecules such as BTA to
form an adsorption layer on the surface of copper. It is found that the strength of the passivation
effect is a function of pH, surfactant structure, surfactant concentration, and counter ions.
In this poster presentation, some background information on CMP slurry requirement and
working principles will be first introduced. A set of comparative experimental results based on
BTA and a surfactant system will be described. The feasibility of using such a surfactant system
for copper CMP slurry formulation, especially in the acidic region such as pH = 5, will be
analyzed. An even broader implication of using such a concept in other anti-corrosion
applications will be further speculated.
ROLE OF PHASE SCIENCE IN COLLOID AND SURFACE SCIENCE
P13-01
Investigations of Emulsion Films using Electrochemical Methodology.
J. CZARNECKI1, D. Exerowa2, K. Khristov2, J. Masliyah3, E. Musiał3 and N. Panchev2,3,
1
Syncrude Canada Ltd., Edmonton Research Centre; 2Inst. Phys. Chem., Bulgarian Acad. Sci.,
3
Dept. Chemical Material Eng., University of Alberta, czarnecki.jan@syncrude.com
A new method for studying properties of thin liquid emulsion films has been developed. The
Exerowa-Scheludko thin liquid film cell was modified by inserting a pair of electrodes into the
water containing compartments. DC voltage applied across the film allowed measurements of a
critical voltage at which the film breaks. A small AC signal was used to measure the film
capacitance. Measurements were conducted for water – Athabasca bitumen diluted with 50:50
mixture of heptane and toluene. The measured changes in the film capacitance can be due to film
thinning and/or changes in the film structure or composition. Build-up of the surface layer that
stabilizes water-in-crude oil emulsions is a slow process taking at least minutes if not hours. The
dependence of the initial rate of change in the film capacitance with time on bitumen
concentration indicates that surface composition at low concentrations is markedly different from
that at high bitumen concentrations.
P13-02
Stratification and “Stained Glass” Behaviour in Foam Films from Complex
Aerosol-OT Solutions.
JAN CZARNECKI1, Jacob Masliyah2, Nikolay Panchev2,3, 1Syncrude Canada Ltd., Edmonton
Research Centre, 2Dept. Chemical Material Eng., University of Alberta, 3Inst. Phys. Chem.,
Bulgarian Acad. Sci., czarnecki.jan@syncrude.com
Stratification of foam films drawn from aqueous Aerosol-OT solutions at concentrations well
below lamellar liquid crystal (LLC) phase boundary is due to layers of ordered micelles.
However, at higher concentrations, where LLC coexists with normal micellar solution in bulk,
film stratification is due to stacked bilayers of surfactant molecules. The distance between the
ordered bilayers, i.e., d-spacing, in the film is smaller than that for the bulk LLC phase. As the
Aerosol-OT concentration increases, the thickness at which the first stratification step occurs
increases and the final equilibrium film thickness decreases. Contrary to popular believe the first
stratification step can occur well above 60-70 nm. Indeed, for films showing LLC-like structure,
film stratification was observed in films several micrometers thick. Here, the film is composed of
a number of domains of uniform color (thus of uniform thickness) with sharp boundaries,
resembling 'stained glass'. Those thick domains may coexist with black film domains, 18 nm
thick, in a single film specimen.
P13-03
Capillary Forces between Surfaces in a Liquid Crystal near its Isotropic-to-Nematic Phase
Transition Temperature
H. SHINTO, K. Kobayashi, T. Hyodo, K. Higashitani, Department of Chemical Engineering,
Kyoto University, Kyoto, Japan, shinto@cheme.kyoto-u.ac.jp
The interaction forces between the particle and plate in 8CB liquid crystal near its isotropic-tonematic transition temperature have been measured in-situ using an atomic force microscope
(AFM) with temperature controllers. As a result, we found that 8CB molecules orient
perpendicular to the DMOAP-coated glass surfaces (i.e., homeotropic orientation), whereas they
orient parallel to the graphite and the carbon surfaces (i.e., homogeneous orientation). When two
surfaces were of the same kind, attractive forces were observed between them. These attractive
forces are attributed to the confinement-induced phase separation of the liquid crystal. On the
other hand, only repulsive forces were observed between two surfaces of the different kind.
P13-04
An ATR-FTIR Study of Dicarboxylic Acids at the Hematite/Water Interface
YU SIK HWANG, John J. Lenhart, Department of Civil and Environmental Engineering and
Geodetic Science, The Ohio State University, Columbus, OH, hwang.156@osu.edu
The focus of the present study is on a molecular-level understanding of the bonding mode and
structure of simple carboxylic acids at the hematite/water interface. We present results for four
simple dicarboxylic acids (phthalic, maleic, fumaric, succinic acid) and investigate how surface
complex structures and modes are affected by small differences in the molecular structures of the
organic acids. Applying attenuated total reflectance Fourier-transform infrared (ATR-FTIR)
spectroscopy and batch adsorption experiments, we characterized the adsorption of these organic
acids to hematite as a function of pH, ionic strength, and surface loading. Our macroscopic
results show that the pH for maximum adsorption is closely related to the pKa2 of these organic
acids. In the circum-neutral pH range the highest adsorption density is found for phthalic acid
and maleic acid, followed by succinic acid. Fumaric acid shows the weakest adsorption. The IR
spectra for adsorbed acids are similar to the spectra for phthalate, maleate, fumarate, and
succinate ion in solution, exhibiting only small variations with pH, ionic strength, and surface
loading. We interpret these IR results to indicate the presence of single dominant fully
depronated outer-sphere complex (i.e., FeOH2+X2-) for all of the dicarboxylic acids in the study.
P13-05
IR-Raman Investigation of the Structure and Energy Transfer Dynamics of a Reverse
Micelle Surfactant Layer
T.D. SECHLER1, J.C. Deak1, Y. Pang2, Z. Wang2, D.D. Dlott2, 1Department of Chemistry,
University of Scranton, Scranton, PA, 2Department of Chemistry, University of Illinois, Urbana,
IL, sechlert2@uofs.edu
IR-Raman spectroscopy is used to analyze the structure and energy transfer dynamics of a
reverse micelle surfactant layer. This technique uses a femtosecond infrared laser pulse to excite
a specific vibrational motion in the system while subsequently monitoring the anti-Stokes Raman
signal with a second laser pulse at varied delay times. The movement of vibrational energy in
the system can then be determined by analyzing the changes in the Raman signal. Also, the
emulsions used in this experiment were formulated such that each structural domain of the
system gave a unique response in the vibrational spectrum of the system allowing for a
correlation between spectral and spatial resolution. Both the rate and mechanism of vibrational
energy transfer across the interfacial region were then measured. The rate of vibrational energy
transfer to the nonpolar continuum is shown to be dependent on where the energy was deposited
into the system.
SYNTHESIS AND CHARACTERIZATION OF NANOMATERIALS FOR ADVANCED
MICROELECTRONIC AND PHOTONIC APPLICATIONS
P14-01
New Liquid Mirrors from Silver Nanoparticles: Optimization of Reflectivity by Controlling
Nanoparticle Size
N. CARUFEL, E.F. Borra, A.M. Ritcey, Center for Optics, Photonics and Lasers (COPL) and
Department of Chemistry, Laval University, QC, Canada, nancy.carufel.1@ulaval.ca
We have been investigating thin reflective surface films of silver nanoparticles at the air-water
interface. Such films represent a new class of liquid mirrors that constitute an excellent
alternative to mercury mirrors because of their low density and low toxicity. The optical
properties of the surface films clearly depend on certain characteristics of the silver nanoparticles
employed in their fabrication. In particular, we have demonstrated that reflectivity depends on
the size and shape of the constituent particles. Larger nanoparticles (80-120 nm) form better
liquid mirrors than do smaller nanoparticles (20-50 nm). For this reason we have investigated the
influence on particle size of various experimental parameters related to the preparation of the
silver colloid. The suspensions of silver nanoparticles are prepared by the citrate reduction of
silver nitrate (AgNO3) in aqueous solution. The concentrations of both silver and citrate ion are
found to influence nanoparticle size in an important way. The exact way in which citrate is
introduced (all at once or stepwise) also has an important effect on nanoparticle formation.
Finally, preliminary results involving the use of small silver particles as precursor seeds suggest
that this procedure has much promise for the control of particle size through the number of germs
introduced. The particles are characterized by transmission electron microscopy. The optical
properties of the surface films are determined with a UV-visible spectrophotometer equipped
with a reflectivity accessory. Future work will include experiments to establish the relationship
between nanoparticle size and surface film thickness.
P14-02
Nanoparticles of Conjugated Polymer and Well-Organized Nanoporous TiO2 Shell
Kwang-Suk Jang, Jae Hyun Jeong, Sung-Ho Cho, JONG-DUK KIM*, Department of Chemical
& Biomolecular Engineering, and the Center for Ultramicrochemical Process Systems, Korea
Advanced Institute of Science and Technology, Daejeon, Republic of Korea, jdkim@kaist.ac.kr
Synthesis of conjugated polymer-TiO2 nanocomposites has been attracted for their useful
applications in optoelectronic devices, such as solar cells, electrochromic devices, light-emitting
diodes, and charge-storage devices, which make a heterojunction between organic and inorganic
semiconductors where charge transfer occurs. A conjugated polymer-TiO2 core-shell
nanocomposite could be obtained by synthesizing polymethineimine and nanoporous TiO2 shell
simultaneously. Polymethineimine was synthesized by the ring opening polymerization of striazine as a complex with metal halide, such as ZnCl2, SnCl4, and TiCl4. In addition, an ordered
array of nanoporous TiO2 was synthesized with frameworks of supramolecular assemblies.
Recently, highly organized nanoporous TiO2 was prepared by hydrolysis of TiCl4 in the presence
of surfactants or amphiphilic block copolymers. In this study, the core-shell nanoparticles of
polymethineimine-nanoporous TiO2 were synthesized within a short time by adding s-triazine to
the mother solution of nanoporous TiO2. The mixture of two triblock copolymers was used as a
template material for nanoporous inorganic shell, and TiCl4 was used as a catalyst for the ringopening polymerization of polymethineimine and as a precursor of TiO2.
P14-03
Synthesis and Characterization of Polymer Encapsulated Nanoparticles for
Microelectronic Applications
PRASHANT MESHRAM, Richard Partch, Center for Advanced Materials Processing and
Department of Chemistry, Clarkson University, Potsdam, NY, rpartch@clarkson.edu,
meshraps@clarkson.edu
There are two well-researched methods for constructing the core-shell morphology of particles.
The shell can be produced by adsorption of preformed macromolecules onto core surfaces by
electrostatic or by non-solvent deposition methods. An alternate method involves mixing core
particles with monomers and then initiating polymerization. This procedure is more favorable for
obtaining a uniform coating of each particle because of the substantially higher accessibility of
the active surface of cores for molecules of a monomer compared to the corresponding
macromolecules. However, the formation of an organic shell on extremely small silica
nanoparticles (~ 20 nm) by the same method has received little attention. In the present work; we
demonstrate a process of coating of such small colloidal silica particles with polymers in two
layers; the first layer is PDVB (polydivinylbenzene) and the second layer is PHEMA (poly2hydroxyethylmetha-crylate). Results of several time based adsorption experiments are presented
to verify the hypothesis of monomer adsorption on inorganic core with and without initiator. The
presence of polymer encapsulating the silica surface was determined by FTIR spectroscopy,
transmission electron microscopy (TEM) and ALV particle sizing instruments; while the amount
of coated polymer on silica surface was assessed by thermogravimetric analysis (TGA). These
polymer coated particles can be used as soft abrasives in CMP application to minimize defects.
SYNTHESIS, CHARACTERIZATION AND APPLICATIONS OF BIOINSPIRED
NANOMATERIALS
P15-01
Formation and properties of polysaccharide-based polyelectrolyte complexes
RODOLPHE OBEID, Piotr Kujawa, Françoise M. Winnik, Department of Chemistry and
Faculty of Pharmacy, University of Montreal, CP 6128 Succursale Centre Ville, Montréal, QC,
Canada
So far the formation of polyelectrolyte complexes has been mainly studied for synthetic
polyelectrolytes. Here we describe the complexation between two charged polysaccharides,
polycationic chitosan and negatively charged hyaluronic acid. Dynamic light scattering shows
that upon mixing these two polymers form submicrometer particles with the hydrodynamic
radius depending on polymer concentration, molar ratio as well as molecular weight of two
complexing polyelectrolytes. Chain length of chitosan is the major parameter affecting the
dimensions of the complexes, i.e. an increase in the molecular weight of chitosan results in the
formation of larger particles. The complexes were additionally characterized by atomic force
microscopy, which shows the granular morphology and the size similar to that determined from
light scattering data. Finally, the thermodynamics of interaction between chitosan and hyaluronic
acid was studied using isothermal titration calorimetry.
P15-02
Enzymatic Synthesis of a Skin Scaffold
KRISHNA BALANTRAPU1, Monisha Madalaywala2, Anja Mueller1*, 1Department of
Chemistry, Box 5810, Clarkson University, Potsdam, NY, 2Department of Chemistry, Carnegie
Mellon University, Department of Chemistry, 5000 Forbes Avenue, Pittsburgh, PA
The objective of skin substitutes is to restore the anatomy and the function of the normal skin
after healing of the wound. Artificial skin grafts heal with extensive scarring and loss of some of
the skin functions.
We are developing a polymeric scaffold based on a cross-linked polysaccharide. Horse Radish
Peroxidase is being used as a catalyst in the synthesis. All the materials synthesized are based on
the Poly(glucuronic acid). Several copolymers and cross-linked polymers will be presented.
Degradation studies of the polymers and the surface characterization will also be included in the
presentation.
15-03
Development and Characterization of Biomimetic Interfaces Using Lipid Bilayer Arrays on
Patterned Polyelectrolyte Templates
Neeraj Kohli, Sachin Vaidya, Robert Y. Ofoli, Robert M. Worden, Ilsoon Lee, Department of
Chemical Engineering and Materials Science, Michgan State University, E. Lansing, MI,
ofoli@egr.msu.edu
We present novel and robust methods to produce arrays of lipid bilayers on patterned
polyelectrolyte multilayers. Such arrays may be useful for high-throughput screening of
compounds that interact with cell membranes, and for probing, and possibly controlling,
interactions between living cells and synthetic membranes. Liposomes composed of 1,2dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phosphate
(monosodium
salt)
(DOPA)
were
found
to
adsorb
preferentially
on
poly(dimethyldiallylammonium chloride) (PDAC) and poly(allylamine hydrochloride) (PAH)
surfaces. On the other hand, liposome adsorption on sulfonated poly(styrene) (SPS) surfaces was
minimal, due to electrostatic repulsion between the negatively charged liposomes and the SPScoated surface. Poly(ethylene glycol) (m-dPEG acid)-coated surfaces were also found to resist
liposome adsorption, as liposomes appear to only bind loosely to these surfaces. These results
were exploited to create arrays of lipid bilayers by exposing PDAC, PAH and m-dPEG patterned
substrates to DOPA/DOPC vesicles of various compositions. The patterned substrates were
created by stamping PDAC (or PAH) on SPS-topped multilayers and m-dPEG acid on PDACtopped multilayers, respectively. We characterized the resulting interfaces by total internal
reflection fluorescence microscopy (TIRFM) along with fluorescence recovery after pattern
photobleaching (FRAPP), quartz crystal microbalance (QCM), and fluorescence microscopy, to
assess the feasibility of this approach. The results suggest that such biomimetic interfaces can be
functionalized for potential applications as biosensors and in biocatalysis.