Tuesday 9 July 2013, Strathblane & Cromdale Halls, 16:30-18:30
Poster session A - Polymer structure and dynamics
P.104 SANS and SAXS Studies for amphiphilic multi-sugar type oligomers in aqueous solutions
K Akutsu1, H Iwase1, T Yoshimura2 and K Nakatani2
1
Comprehensive Research Organization for Science and Society, Japan, 2Graduate School of Humanities and
Sciences, Nara Women’s University, Japan
Amphiphilic multi-sugar type oligomer, which is sugar-based surfactant, has attracted attention as new type
surfactants having favorable characteristics such as biocompatibility and biodegradability. Recently, we
successfully synthesized new amphiphilic multi-sugar type oligomers, C12-mGEMA (m denotes polymerization
degree, GEMA is a glucosyloxyethyl methacrylate) with an alkyl chain. The aggregation properties in aqueous
solution were investigated by using small-angle neutron and X-ray scattering (SANS and SAXS) techniques.
SANS and SAXS experiments were performed on BL15 at J-PARC and BL40B2 at SPring-8, respectively. SANS and
SAXS results suggested that aggregates formed by C12-3.0GEMA and C12-4.0GEMA are globular micelles with the
radius of ca. 2 nm, and the C12-mGEMA aggregates become from globular micelles to ellipsoidal micelles with
increasing the polymerization degree. To determine structural parameters quantitatively, we employed a modelfitting analysis using a scattering function of core-shell ellipsoidal particles. The results of the model fitting analysis
will be presented.
P.105 Ring rotation dynamics of ferrocene and ferrocene-containing polymers
M Appel1, B Frick1, M Zbiri1, T Spehr2, J Elbert2, M Gallei2 and B Stühn2
1
ILL, France, 2TU Darmstadt, Germany
Ferrocene (Fc) is an organometallic compound consisting of two cyclopentadienyl rings with a reversibly oxidizable
iron atom sandwiched in between. When oxidized, the Fc complex exhibits a magnetic moment making Fccontaining polymers suitable candidates as magnetic 'soft control' materials.
In bulk Fc past neutron scattering studies of the ring rotation dynamics mainly focussed on the high temperature
phase [1]. We refine these experiments and extend results to the low temperature phase using neutron time-of-flight
and backscattering experiments including the new possibility of inelastic fixed window scans on IN16 at the ILL [2].
Furthermore, we include ferrocenium triiodide with oxidized Fc complexes in our studies. In contrast to previous
findings our data suggest jump rotation dynamics on 10 sites instead of 5. The measured barrier of internal ring
rotation is in good agreement with DFT simulations.
In poly(vinylferrocene), the ferrocene complex is laterally attached to a polymer chain. We use polarized neutron
diffraction to separate coherent from incoherent scattering. The combination of diffraction and spectroscopy enables
us to extract the elastic incoherent structure factor (EISF). The resulting EISF supports the assumption that only one
ring of the ferrocene sandwich complex is rotating.
[1]
[2]
Gardner et al., Chem. Phys. 57, 453 (1981)
Frick et al., Nucl. Inst. and Methods A 669, 7-13 (2012)
ICNS 2013 International Conference on Neutron Scattering
P.106 Observation of polymer dependent reentrant phase behavior in charged nanoparticle system
V Aswal1, S Kumar1, V Aswal1 and J Kohlbrecher2
1
Bhabha Atomic Research Centre, India, 2Paul Scherrer Institute, Switzerland
Small-angle neutron scattering has been carried out to examine the polymer (PEG) induced depletion interaction of
charged nanoparticles (Ludox silica) in aqueous solution. The polymer-nanoparticle system interestingly show a
reentrant phase behavior where the nanoparticles undergo particle clustering and back to individual nanoparticles
as a function of polymer concentration. The resultant interaction in these systems is governed by the competition of
the short-range as well as long-range attraction and repulsion. The data are fitted using combination of two Yukawa
potentials accounting for attractive depletion and repulsive electrostatic forces. The depletion interaction is found to
be long-range attraction and clustering of charged nanoparticles observed as a consequence of dominance of
depletion interaction over long-range electrostatic repulsion. The concentration dependent polymer adsorption is
believed to be the reason for the reentrant phase behavior as the combination of steric and electrostatic repulsions
at lower and higher polymer concentrations dominates over the depletion interaction. The clusters formed under
depletion interaction are large-sized (order of micron) and characterized by the surface fractal structure with simple
cubic type packing of particles within the clusters.
P.107 Nanoparticle influence on elastomer matrix modelling from SANS and SAXS Data
A M Balasoiu Gaina1, M Balasoiu2, A Rogachev3, O Ivankov3, A Zhigounov4 and I Ionita5
1
Moscow State University, Russia, 2JINR/IFIN-HH, Russia, 3JINR, Russia, 4IMC ASCzR, Russia, 5INR, Russia
The study of the properties of filled elastomers is a challenging and exciting topic for both fundamental science and
industrial application. It is known that adding of hard particulates to a soft elastomer matrix results in the properties
that do not follow a straightforward rule of mixtures.
In the present paper the microstructure properties of rubber elastomer matrix samples polymerized with ferrofluid
and nanoparticles produced from Fe(CO)5thermal decomposition are investigated .by means of small-angle neutron
and X-ray scattering experimental data using the fractals approach.
P.108 Small angle neutron scattering in soft magnetic elastomers
M Balasoiu1, G Stepanov2, Y Raikher3, A Kuklin4, D Soloviev4, A C Dragolici5 and I Ionita6
1
JINR/IFIN-HH, Russia, 2SSRICTOC, Russia, 3ICMM, Russia, 4JINR, Russia, 5IFIN-HH, Russia, 6INR, Russia
New generation of magnetic elastomers represents a new type of composites consisting of small magnetic particles,
usually in the nano- or micrometer range, dispersed in a highly elastic polymeric matrix.In recent years, polymer
composite materials with mechanical and rheological properties that are dramatically changed under the action of
external magnetic fields have been synthesized and are intensively studied [1-3].
The aim of this work is the small-angle neutron scattering examination of subtle structural features of polymeric
matrix and ensemble of embedded ferroparticles as resulted from the conditions of preparation of ferroelastomers
by the variation of concentration of ferroparticles and the strength of a longitudinal and orthogonal to the sample
surface external magnetic field applied during the polymerization process for a new type of a highly elastic
polymeric matrix.
The samples were investigated by small angle neutron scattering at the YuMO-SANS spectrometer [4] in function at
IBR-2 reactor, Dubna.
ICNS 2013 International Conference on Neutron Scattering
[1]
[2]
[3]
[4]
D. Szabo, G. Szeghy, and M. Zrinyi, Macromolecules 31 6541 (1998)
S. S. Abramchuk, D. A. Grishin, E. Yu. Kramarenko, G. V. Stepanov, A. R. Khokhlov,Polymer Science A 48(2)
138 (2006)
G. Stepanov, D. Borin, S. Odenbach, J. of Phys.: Conference Series 149 012098(4pp) (2009)
Neutron instrumentation at IBR-2, FLNP User Guide, Ed. O. Culicov (http://flnp.jinr.ru/img/27/1030_userguide-site-version.pdf)
P.109 Investigating the electrodeposition of polypyrrole using in situ neutron reflectometry
C Beebee1,2, A R Hillman2, K S Ryder2, E B Watkins1, R M Brown2 and V Ferreira2
1
Institut Laue-Langevin, France, 2University of Leicester, UK
Interest in intrinsically conducting polymer materials for use in electronic devices places great importance on
understanding the fundamental properties and structural details of these systems. Films can be polymerised and
deposited by chemical, mechanical or electrochemical methods. There is substantial evidence indicating that each
film preparation method results in different physical structures and/or electrochemical behaviour of these materials;
this has been the motivation for undertaking this research.
Here we describe the use of neutron reflectometry to probe the internal structure of films of the conducting polymer,
polypyrrole (PPy), deposited electrochemically. The films are grown in a customised cell that permits in situ
reflectivity measurements during the deposition process. The effect of the growth method (potentiodynamic,
potentiostatic or galvanostatic) on structure is explored. The electrodeposition conditions (e.g. scan rate, number of
cycles, anodic limit potential, deposition charge and current) were selected envisaging the formation of PPy films
with similar thickness; all other conditions such as monomer concentration and electrolyte were kept constant. The
resulting electrochemical behaviour and polymer structure are analysed and discussed, with the benefit of
supporting morphological characterisation using surface imaging techniques (AFM and SEM) to provide topological
features for each deposition protocol.
P.110 Complementary vibrational spectroscopy studies of novel iodonium photoinitiators for cationic
polymerization
D Chudoba1, K Drużbicki2 and J Ortyl3
1
Joint Institute for Nuclear Research, Russia, 2Department of Chemical Physics, Faculty of Chemistry, Jagiellonian
University, Poland, 3Institute of Chemistry and Technology, Cracow University of Technology, Poland
One of the hottest topics in polymer science, being the subject of numerous industrial and academic studies, is
photoinduced cationic polymerization (PICP). Radiation cure technology has found a number of industrial
applications because it is fast, efficient, and solvent-free. Its applicability and common usage may be expressed by
the examples of light-polymerized dental composite materials or photocurable coatings used in the polygraphic
industry. The iodonic photoinitiators are the class of innovative compounds with a real applicable potential in
cationic polymerization due to their good absorption characteristics in the UV range, matching the spectral
characteristic of the commercially available middle pressure mercury lamps, and their good efficiency as
photoinitiating processes.
In our project we are focused on the ground state structural-vibrational aspects. The selected coumarine’s iodonium
derivatives were structurally characterized by using X-Ray diffraction and complementarily studied with vibrational
optical and neutron spectroscopy. INS along with Infrared and Raman measurements have been performed. The
experimental studies were strongly supported by theoretical calculations, performed using modern quantumchemical tools, including linear-response periodic boundary conditions computations in frame of density functional
theory, delivering a complex view into the vibrational dynamics of the studied systems.
ICNS 2013 International Conference on Neutron Scattering
P.111 Separation of collective and single-particle dynamics in a pyridinium-based Ionic liquid by means of
polarized neutrons
J P Embs1, T Burankova1 and R Hempelmann2
1
Paul Scherrer Institut, Switzerland, 2Saarland University, Germany
The analysis of QENS data measured on hydrogen-rich organic samplesis usually started with the assumption that
the incoherent signal from hydrogen determines the total scattering intensity, while the coherent contributionis
considered to be negligible.On the other hand the static structure factor ofmany ionic liquids features so-called prepeaks in theQ-range accessible normally by QENS; andthusthis assumption for such kinds of samples is
questionable. Here we report experiments on separation of collective and single-particle contributions of the total
scattering intensity of [BuPy][Tf2N](1-butylpyridinum bis(trifluoromethylsulfonyl)imide), performed on the cold
neutron multidetector time-of-flight spectrometer with polarization analysis D7 at Institute Laue Langevin, France
[1]. The intensity of the coherent part, which describes collective dynamics, follows the static structure factor ofthe
totally deuterated sample measured on the diffractometer HRPT at the Swiss spallation source SINQ.Thequasielastic
broadening ofthecoherent contribution corresponds to a slow collectivemotion on the timescale ofseveral
picoseconds. The incoherent intensity decreases monotonously withQ and can be characterizedby two processes: a
slow motion (of the whole cation), which is diffusive in nature and faster localized dynamics, associated with chain
and ringlibrations.
[1]
J.P.Embs , T.Burankova, E.Reichert, R.Hempelmann, J.Phys.Chem.B 2012, 116, 13265-13271
P.112 SANS investigations of functionalized single wall carbon nanotubes dispersed in block copolymer systems
J-M Ha, H-S Jang, S-H Lim and S-M Choi
Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Korea
Single-walled carbon nanotubes (SWNTs) have remarkable electrical, thermal, and mechanical properties which
provide a broad range of potential applications. Self-assembly or guided assembly of SWNTs into highly ordered
superstructures with well defined morphology, density, and direction has been of great interest as a route to
collectively enhance their physical properties and is the key to the realization of various potential applications of
SWNTs. Block copolymers exhibit rich phase behaviors and have been extensively used as excellent templates for
various nanostructured materials. Many efforts have been made to incorporate various nanoparticles into selfassembling block copolymers as an efficient and scalable way of fabricating well-controlled and highly ordered
nanoparticle superstructures with various architectures. Recently, this approach has been successfully applied for
SWNTs [1, 2, 3] but it is in its very early stage. In this presentation, we will report the contrast matched small angle
neutron scattering investigations on the selective distribution of hydrophilically functiontionalized SWNTs in Pluronic
block copolymer systems at different phases.
[1]
[2]
[3]
C. Doe, H.-S. Jang, T.-H. Kim, S. R. Kline, and S.-M. Choi, J. Am. Chem. Soc., 131, 16568 (2009)
H.-S. Jang, C. Do, T.-H. Kim, and S.-M. Choi, Macromolecules, 45, 986 (2012)
H.-S. Jang, T.-H. Kim, C. Do, M.-J. Lee, and S.-M. Choi, Soft Matter, ASAP (2013)
ICNS 2013 International Conference on Neutron Scattering
P.113 Aggregation properties of gemini-type amphiphilic dendrimers in aqueous solution investigated by SANS and
SAXS
H Iwase1, K Akutsu1, N K Kawano2, A Ebihara2 and T Yoshimura2
1
Comprehensive Research Organization for Science and Society, Japan, 2Graduated School of Humanities and
Sciences, Nara Women's University, Japan
A gemini-type amphiphilic dendrimer, which consist of two poly (amidoamine) (PAMAM) dendrons (generation
number of 1 – 5) and alkyl-chains connected by spacer chains have been successfully synthesized. By employing
surface tension measurements, the gemini-type amphiphilic dendrimer was shown to have a higher efficiency in
lowering the surface tension of water. Moreover, the dendrimer-head moiety was more efficiently packed at the airliquid interface. In this study, in order to reveal aggregation properties of gemini-type amphiphilic dendrimers in
aqueous solutions, by combining the use of small-angle neutron scattering (SANS) and small-angle X-ray scattering
(SAXS), we investigated the meso-scale aggregate behavior of the amphiphilic dendrimer in aqueous solutions with
varying generations, sample concentrations, and pH, respectively. SANS and SAXS measurements were performed
on the SANS instrument (TAIKAN) installed at BL15 in the MLF Facility in J-PARC and on BL40B2 station at SPring8. In order to determine structural parameters quantitatively, we employed model-fitting analysis using a scattering
function of charged core-shell spherical particles. The results of these experiments will be discussed in this
presentation.
P.114 Neutron reflectivity studies on the release mechanism of model polymer multilayer thin films: Enthalpic and
entropic aspects of the release
Y Jang1, J Seo1, B Akgun2, S Satija2 and K Char1
1
The National Creative Research Initiative Center for Intelligent Hybrids, The WCU Program of Chemical Convergence
for Energy & Environment, School of Chemical & Biological Engineering, Seoul National University, Korea, 2NIST
Center for Neutron Research, NIST, USA
The layer-by-layer (LbL) deposition has received a great deal of attention because it is regarded as one of the
powerful methods to design functionalities within multilayer thin films by controlling intermolecular interactions
between neighboring layers. However, the structural changes within the LbL films during stimuli-triggered release
process have so far not been well understood because of difficulty in detecting the internal structure of multilayered
thin films. In the present study, we have monitored the pH-induced changes in the internal structure and, at the
same time, corresponding in-situ changes in physical properties of LbL films as a function of external pH by using
neutron reflectivity (NR) and quartz crystal microbalance with dissipation (QCM-D). The model multilayer thin films
investigated in this study have been designed with different physical parameters for the polyelectrolytes (PEs) (i.e.,
types of PEs (strong and weak), charge density and molecular weight), which are, in turn, closely related to the
intermolecular interactions between the layers. We confirmed that the burst erosion of pure weak PE multilayer films
was dramatically suppressed and transformed into the surface erosion by blending with strong PEs within the films
or by increasing the molecular weight of weak PE chains. The results shown in the present study would yield
fundamental information on the effect of enthalpic and entropic adsorption nature of PEs on the stimuli-triggered
changes in the motion of PE chains (either swelling or release) within the LbL multilayer films.
ICNS 2013 International Conference on Neutron Scattering
P.115 Neutron scattering for polymer chain conformation in nanocomposites
J Jestin, C Chevigny, N Jouault, A-S Robbes, F Cousin and F Boué
Laboratoire Léon Brillouin, France
We present different SANS determination of the polymer chain conformation in model nanocomposites in
correlation with particle dispersion and mechanical reinforcement. On a first silica/polystyrene system [1], we show
using the Zero Average Contrast (ZAC) method combined with SAXS and TEM, that the polymer chain is not modified
by the fillerat rest [2] and under deformation [3] illustrating that chain deformation does not contributed
significantly to reinforcement. With magnetic nanoparticles, we succeeded in orientate the filler in a 1D network with
an external magnetic field [4]. Thanks to a SANS extrapolation method, we show that the polymer chain
conformation appears to be not affected by filler orientation despite of strong anisotropic reinforcement [5]. We can
finally control with grafting [6,7] the particle dispersion in polystyrene matrix, individual or aggregates, with the
grafted to free chain ratio [8,9]. Using a specific SANS contrast variation method, we demonstrate that these
dispersions can be related to a collapsed or stretched conformation of the grafted brushes [10] while the elastic
modulus seems to depend mainly on the local particle-particle interactions.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
Jouault et al. Macromolecules 42, 2031, 2009
Jouault et al. Physical Review E 82, 031801, 2010
Jouault et al. Macromolecules 43, 9881, 2010
Jestin et al. Advanced Materials 20, 2533, 2008
Robbes et al. Macromolecules 44, 8858, 2011
Chevigny et al. Soft Matter 5, 3741, 2009
Robbes et al. Soft Matter 8, 3407, 2012
Chevigny et al. Macromolecules 44, 122, 2011
Robbes et al. Macromolecules 45, 9220, 2013
Chevigny et al. Macromolecules 43, 4833, 2010
P.116 SANS study of temperature- and pH-responsive systems: from block copolymers to clusters
A Joset, P Sibret, C Jérôme and B Leyh
University of Liège, Belgium
A SANS study of pH- and temperature-responsive systems built from triblock copolymers of polyacrylic acid (PAA),
poly(N-isopropylacrylamide) (PNIPAM) and poly(ethylene oxide) (PEO) is presented. At low pH, PAA is neutral and
hydrophobic, while at higher pH, it becomes a hydrophilic polyelectrolyte. PNIPAM is hydrophilic below its lower
critical solution temperature (32°C) and hydrophobic at higher temperature [1]. SANS measurements have been
performed under several conditions (pH=2, 6 and 8; T = 20, 30, 40 and 50°C). Two samples were studied: PAA13b-PNIPAM45-b-PEO45 and PAA11-b-PNIPAM46-b-PEOd6;46 (with deuterated PEO), both in D2O.
Dynamic light scattering and SANS reveal a bimodal size distribution assigned to micelles and clusters. An
estimation of the average size of these objects and of their polydispersity has been obtained by assuming hard
spheres or using Guinier’s law and Gaussian size distributions.
At acidic pH, the number of clusters increases with temperature: PNIPAM becomes hydrophobic and the PEO chains
can no longer prevent coalescence. At basic pH, almost all chains are solubilized and some are included in clusters.
Upon temperature increase, micellization takes place to some extent.
Analysis of the SANS cross sections is attempted by describing the micelles by the Pedersen and Gerstenberg
model [2], whereas homogeneous spheres are assumed for the clusters. These results are correlated with dynamic
light scattering and electronic microscopy.
ICNS 2013 International Conference on Neutron Scattering
[1]
[2]
Macromol. Rapid Commun. 21, 476–480 (2000)
Pedersen, J. S.; Gerstenberg, M. C. Macromolecules 1996, 29, 1363-1365
P.117 Time resolved SANS study on guest exchange processes of syndiotactic polystyrene
F Kaneko1, A Radulescu2, N Seto1 and K Ute3
1
Osaka University, Japan, 2JCNS, Japan, 3Tokushima University, Japan
Syndiotactic polystyrene (sPS) is a relatively new commodity polymer, which exhibits a variety of solid states. One
of the important properties of sPS is the formation of crystalline complexes, where low-mass molecules are stored
as guests in the cavities or channels between polymer helices. The guest in the cavities is easily substituted with
another compound by exposing the complex sPS film to its vapor or liquid, keeping the framework of the host sPS
lattice. By using this phenomenon, a wide range of chemical compounds including functional molecules can be
incorporated into the crystalline region of sPS. The combination of sPS complex and guest exchange is considered
to be promising for the development of a new kind of polymer based composite materials.
Exploiting the difference in molecular scattering length between two isotopologues, fully protonated (H) and
deuterated (D) forms, employed as old and new guests, we started to investigate the characteristics and
mechanism of the guest exchange through time-resolved high intensity SANS at FRM II reactor. By measuring the
lamellar reflections with uniaxially oriented samples, the guest exchange process could be followed. The guest
exchange between H and D guests caused a significant intensity change in the lamellar reflections. It has been
revealed that the guest exchange proceeds smoothly, keeping the higher order structure of the sPS complexes. The
analysis using the one-dimensional correlation function Γ1(x) delivered the information how the distribution of old
and new guests in the lamellae varies during the exchange process, and suggested that the exchange proceeds from
the lamellar surface region to the interior.
P.118 Nanostructures and particle arrangement in block copolymer film
E Kim1, Y-S Han1, B Seong1 and D Y Ryu2
1
Korea Atomic Energy Research Institute, Korea, 2Department of Chemical and Biomolecular Engineering, Yonsei
University, Korea
Abstract unavailable
P.119 Continuous phase behavior in diblock copolymer mixtures
Y Kim1, Y Lee1, H Ahn1, H Lee1, Y S Han2 and D Y Ryu1
1
Yonsei University, Korea, 2Korea Atomic Energy Research Institute, Korea
The phase behavior of multi-component polymeric materials determines the compatibility in most of practical
applications involving polymer blends and block copolymers (BCPs). A blend system with the upper critical solution
transition (UCST) behavior shows that non-favorable segmental interactions weaken with increasing temperature,
while a blend system with the lower critical solution transition (LCST) behavior dictate an increasing entropy
correlated to an increase of free volume (or thermal expansion coefficient) with increasing temperature. Very similar
to binary polymer blends, the phase behavior of diblock copolymers has been known to exhibit a microphase
separation from an ordered to a disordered state either upon cooling or upon heating. These two behaviors called
the order-disorder transition (ODT) and the lower disorder-order transition (LDOT) have the different driving forces
with enthalpic and entropic origins, respectively.
ICNS 2013 International Conference on Neutron Scattering
In this study, we will discuss the phase behavior for the binary block copolymer (BCP) mixtures composed of a
weakly interacting (with no specific interaction) polystyrene-b-poly(alkylmethacrylate) (PS-b-PAMA) copolymers
using small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS), and depolarized light scattering
(DPLS).
P. 120 The very cold neutrons scattering on super molecular structure elements of various forms and sizes
S Kuznetsov1, I Meshkov1 and A Shelagin2
1
P. N. Lebedev Physical Institute (LPI), Russia, 2Moscow Institute of Physics and Technology, Russia
The method for materials researches based oneself on the unique properties of the very cold neutrons (VCN) had
been developed in Lebedev Physical Institute [1]. The VCN wavelengths are in the nanometer range. Information
about the super molecular structures (SMS) of various natures can be obtained by analyzing the VCN scattering
cross-sections dependences with using the first Boron approximation. In this case the VCN scattering cross-sections
depends on the correlation function of nuclear optical potential fluctuations. The analytical expressions for the
cross-sections of VCN scattering on structure elements of various forms were obtained.The theoretical wave vector
modulus dependences of differential and integral cross sections of VCN scattering on spherical and cylinder SMS
elements in the region when the conditions for applicability of BA can be disrupted were obtained.
Experimental dependences for various materials were obtained by VCN time-of-flight spectrometer developed in
P.N. Lebedev Physical Institute and situated on the Moscow Engineering Physics Institute research reactor. VCN
transmission and reflection methods were used to study the nanostructure of various co-polymers, polyolephyne
based nanocomposites as well as of many other new materials [2].
[1]
[2]
V.G. Grinev, A.I. Isakov, V.G. Krasheninnikov, N.Yu. Kovaleva, S.P. Kuznetsov, I.V. Meshkov, L.A
Novokshonova, A.D. Perekrestenko, A.V. Shelagin., D.A. Shelagin, Polymer Science (Vysokomolekulyarnye
Soedineniya), Vol 40A, 1763 (1998)
S.P.Kuznetsov at al, Acta Physica Polonica A, Vol.117, No.5, 727 (2010)
P.121 Segment distributions of deuterated diblock in binary blends of block copolymer having hydrogen bonding
J Kwak1, J K Kim1 and S H Han2
1
POSTECH, Korea, 2University of Delaware, USA
A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to
obtain various microdomains that could not be expected for neat block copolymer. For instance, we reported that
the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyreneblock-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and
PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To
explain the unexpected results, one should investigate the exact location of short block copolymer chains in the
interface. For this purpose, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (d-PS-bPHS) and prepared a binary mixture with PS-b-P2VP. Through SAXS and neutron reflectivity (NR), the exact location
of shorter dPS block in the mixture near the interface of the microdomains was investigated.
ICNS 2013 International Conference on Neutron Scattering
P.122 Interfacial Roughness of polymer/polymer Interfaces on Grafted PS Substrates
H Lee1, Y Kim1, D Y Ryu1, T Hirata2, N L Yamada3 and K Tanaka2
1
Yonsei University, Korea, 2Kyushu University, Japan, 3Japan Proton Accelerator Research Complex, Japan
The interfacial roughness of polymer/polymer layer can be a key parameter for determining interfacial interactions
between the two polymer layers. In this study, we investigated the interfacial roughness of polymer/polymer
interfaces on grafted polystyrene (PS) substrates using neutron reflectivity experiment (SOFIA beam line at J-PARC,
Japan). For the neutron contrast, deutrated-polystyrene (dPS) with varied thickness was placed on several
underlying substrates of grafted PS brushes, which were prepared with hydroxyl-terminated polystyrenes (PSOHs).
The controlled brush properties such as grafting density and chain length were set depending on the molecular
weights of PSOHs.
We focused on interfacial roughness in simulation calculation in terms of inter-penetration depth for polymer chains
at polymer/polymer interfaces. Through the comparative analysis with the previous results on theoretical
consideration, we will discuss the relationship of inter-penetration depth with dewetting and glass transition
behavior in bi-layered polymer thin film systems.
P.123 Effects of alkyl side group on phase behavior of polystyrene-b-poly(alkyl acrylate) : Neutron scattering
measurements and theoretical consideration
J Lee1,3, H Ahn2, D Y Ryu2, K Shin3 and J Cho1
1
Dankook University, Korea, 2Yonsei University, Korea, 3Sogang University, Korea
We have investigated the phase behavior for deuterated polystyrene-b-poly(alkyl acrylate)s(dPS-b-PAA) which have
two different length scale in thin films by using neutron reflectivity, neutron small-angle neutron scattering (SANS),
and depolarized light scattering (DLS). The unusual phase behaviors in thin film, which was based on the
experimentally observed reflectivity data, can be understood by Flory-Huggins interaction parameter chi which
dominates the phase behavior of copolymer. The empirical chi, determined from SANS profiles, was theoretically
understood by a combination of a strong entropic and a weak enthalpic contribution. dPS-b-PAA copolymers which
have the pendant group, were shown uncommon phase behavior from the steric hindrance of long alkyl side group.
The order-disorder transition (ODT) temperature for copolymers with the controlled molecular weights were
determined by using SANS and DLS and we will discuss their pressure response up on ODT transition experimentally
and theoretically.
P.124 SANS reveals nanostructural changes of fibres in linen fabric textiles
A Len and L Rosta
Wigner Research Center for Physics, Hungary
Natural organic fiber textiles are subject to deterioration. The changes in macroscopical properties due to various
treatments (e.g. cleaning) or with passing of the time are inevitable, thus investigations for industrial/commercial
purposes or in the field of preservation of historical objects are of great interest. The macro- and microscopical level
changes of the material structure are always connected to structure alterations at nanoscale level. SANS is a
powerful tool for structural studies at this level and it is particularly suitable for archeological textiles because of its
non-destructive nature. Investigations on non archeological linen fibers were carried out in order to prepare an
adequate background for studies of industrial as well as museum objects. The fibers were submitted to different
conditions, such as humidity, temperature, treated with different chemicals and the nonstructural changes were
followed by SANS.
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P.125 Electrostatic self-assembly investigated by time-resolved SANS
G Mariani1,2, R Schweins1 and F Gröhn3
1
LSS Institut Laue-Langevin, France, 2ICMM Erlangen-Nürnberg Universität, Germany, 3University of ErlangenNürnberg, Department for Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Germany
Self-assembly is an effective method to produce complex macromolecular structures. Recently we have introduced
an electrostatic self-assembly approach for the formation of well-defined and responsive supramolecular nanoobjects in aqueous solutions [1]. Building blocks are polyelectrolytes and multivalent organic counterions:
depending on their architecture, aggregates with varying shapes can be formed [2]. Furthermore the understanding
of the self-assembly process is still incomplete.
After the characterization of the nanoparticle structures, we have studied for the first time the self-assembly process
directly in-situ. We have developed a new SANS cell (now installed on D11 instrument at ILL) that allows us to
prepare the nanoparticles in a very fast, uniform and reproducible manner. We analyzed nano-particles made of
PAMAM dendrimers generation 4 and organic divalent dyes (e.g. Ar26). This system is pH switchable as the
dendrimer charge is pH dependent; the new cell allows an optimal control of the solution pH. First results have
shown a different particle structure depending on the pH of the solution. At pH 3.5 both primary and tertiary amines
of the dendrimer are fully protonated and the formation of the final nano-particles occurs, at a pH around 7 only the
primary amines are protonated and we observe the formation of different stable nanoparticles. Above pH 10 no
amines are protonated and no aggregation occurs. We will present the new cell and the first time-dependent results.
[1]
[2]
F. Gröhn, Soft Matter, 6, 4296 (2010)
I. Willerich, F. Gröhn, J. Am. Chem. Soc., 133, 20341 (2011)
P.126 Molecular dynamics on the onset of self-diffusion
H Morhenn1, S Busch2 and T Unruh1
1
University of Erlangen-Nuremberg, Germany, 2University of Oxford, UK
The short-time dynamics leading to self-diffusion in molecular melts are of complex nature due to the overlapping of
intra- and intermolecular contributions. To characterize these dynamics in detail for a short- (C16H34) and longchain (C100H202) n-alkane system resolution resolved quasielastic neutron scattering (QENS) experiments were
carried out. An analysis of the resulting scattering functions yields a crossover of different motions on the pico- to
nanosecond timescale. In order to identify these relaxations extensive molecular dynamics (MD) simulations were
performed. The intermediate scattering functions calculated from the MD simulations are in great accordance with
the QENS data, justifying the extraction of detailed dynamical properties. The evaluation of the local chain
relaxations reveals that collective intermolecular flow-like motions of atoms take place on a timescale framed by
local reorientational and long range diffusional motions. Hence any model not taking these collective features
explicitly into account cannot describe the molecular dynamics in detail. Similar flow-like motions were found in
phospholipid membranes. For these two-dimensional molecular systems dynamic heterogeneities could be
observed, underlining the major effect of intermolecular interactions.
ICNS 2013 International Conference on Neutron Scattering
P.127 Detailed dynamical landscape in ionic micelles
R Mukhopadhyay1, V K Sharma1, S Mitra1 and V Garcia Sakai2
1
Solid State Physics Division, Bhabha Atomic Research Centre, India, 2ISIS Facility, Rutherford Appleton Laboratory,
UK
Local dynamics of self assembled aggregates (such as micelles, vesicles etc.) are important in understanding
various properties such as the mechanism in releasing the solubilized drugs, micellar breaking time, etc.
Quasielastic neutron scattering (QENS) study on sodium dodecyl sulfate (SDS) and cetyltrimethylammonium
bromide (C16TAB) micelles revealed the details of the fast local dynamics of surfactant molecules in these
assemblies and their correlation with the microstructure. QENS data obtained from different time of flight
spectrometers covering wide energy transfer range show the presence of three distinct motions; global motion of the
whole micelles, segmental motion of the monomers and a fast conformational dynamics. The global motion follows
Fick’s law and it is found to be slower for C16TAB than SDS micelles. This may be attributed to the difference in their
hydrodynamic diameters. The segmental dynamics within a micelle has been described with a model, which
accounts for the dynamics of head group and the hydrophobic alkyl chain separately. Flexibility of the alkyl chain
manifests in a form where the hydrogen atoms move within spherical volumes. Sizes of the confining spheres and
corresponding diffusivities of the hydrogen atoms increase linearly from head towards tail. It is found that the
increase in chain length of the surfactant hinders both internal and global dynamics of CnTAB micelles. This is
explained in terms of counterion condensation which results in the growth of micelles and denser packing of the
monomer. Results obtained from molecular dynamics simulation, carried out in parallel to get detailed insight on
the dynamical processes, are found to be consistent with the experimental results.
P.128 Inelastic neutron scattering of organic ferroelectric croconic acid
S Mukhopadhyay1, M Gutmann2, M Jura2, D Jochym3, M Jimenez-Ruiz4, K Refsn3 and F Fernandez-Alonso2
1
STFC Rutherford Appleton Laboratory, UK 2ISIS Facility, STFC Rutherford Appleton Laboratory, UK, 3Scientific
Computing Department, STFC Rutherford Appleton Laboratory, UK, 4Institut Laue Langevin, France
Croconic Acid is the first single component organic molecule which shows room temperature ferroelectricity in its
crystalline form1. Ferroelectric materials are technologically important for their use in non-volatile memory elements
and high K dielectrics.2. Organic ferroelectrics are potentially important for their low cost, flexible structure and low
processing temperatures2. To exploit organic ferroelectric materials for industrial use, however, it is important to
understand the microscopic origin of their ferroelectricity.
Temperature dependent neutron diffractions and inelastic neutron scattering (INS) experiments are done to
understand the structure and vibrational properties of croconic acid. Two characteristic peaks at 895 cm -1 and 958
cm-1 are identified at 5K. Temperature dependent INS studies show that both peaks softened with increasing
temperature.
Experimental vibrational spectra are compared with state-of-the-art calculations based on plane wave pseudo
potential density functional theory using the CASTEP code and the PBE-GGA functional3. The calculated INS spectra
show that two characteristic peaks are due to two types of hydrogen bonds, so called 'terrace' and 'hinge' type,
present in crystalline croconic acid3. Temperature dependent investigations show that vibrational frequency for the
'terrace' type bond softens faster than the 'hinge' type. From the calculation of Born effective charge tensor, we
predict that the 'hinge' type bond has a dominant role in the ferroelectric properties of the crystal.
[1]
[2]
[3]
S. Horiouchi, et al., Nature, 463, 789 (2010)
A. Stroppa, et al., Phys. Rev. B, 84, 014101 (2011)
F. Fernandez-Alonso, et. al., J. Phys. Soc. Japan, to be published (2013)
ICNS 2013 International Conference on Neutron Scattering
P.129 Self-assembly of dPS-liquid crystalline diblock copolymer in a nematic liquid crystal solvent
S-Y Park, T Kamal, T Islam and D-H Kim
Kyungpook National University, Korea
A diblock copolymer (dPS(9.1k)-b-LCP(7.2k), the number in parenthesis represents the number averaged molecular
weight) with a deuterated polystyrene (dPS) block connected to a side group liquid crystal polymer [poly (6-(4’cyanobiphenyloxy)hexyl acrylate, LCP] was self-assembled into 78 Å spherical micelles with a dPS core and LCP
corona in a small-molecule nematic liquid crystal solvent, 4-pentyl-4’-cyanobiphenyl (5CB). The micellar structures
were examined by small angle neutron scattering (SANS) at various block copolymer concentrations and
temperatures. The SANS data was analyzed further using a curve fitting method. The critical micelle concentration
(CMC) was as low as 0.0027 wt% and the self-assembled micelles were dissociated reversibly into a unimer
state at 33˚C, which is lower than the nematic to isotropic transition temperature (Tni) of 5CB (36 °C). The entropic
penalty imposed on the dPS by the ordered nematic state of the LC solvent caused phase separation of the flexible
dPS block to form micelles and vanished above the Tni of the LC solvent. A low CMC of 0.0027 wt% suggests that
5CB was a strong selective solvent of dPS-b-LCP in the nematic state. The global orientation of 5CB, produced by a
magnetic field (MF, 1.2 Tesla) revealed the structure of the dPS core of the micelle to be prolate (elongated sphere)oriented with the long axis along the applied magnetic field direction.
P.130 Inelastic neutron scattering of alpha and beta anomers of methyl-D-xylopyranoside
S Rudic
ISIS Facility / Science and Technology Facilities Council, UK
Abstract unavailable
P.131 Temperature and time dependent clustering and dissolving of dimethylaminoethyl triazole propanoyl
branched poly(ethyl methacrylate)
J Ryu1, H-I Lee2, J-H Sim1 and D Sohn1
1
Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, Korea, 2Department of
Chemistry, University of Ulsan, Korea
Poly(2-((3-(1-(2-(dimethylamino)ethyl)-1H-1,2,3-triazol-4-yl)propanoyl)oxy)ethyl methacrylate), P1, was prepared
and its solution properties were probed with SANS (small angle neutron scattering) and DLS (dynamic light
scattering). P1 exhibited cloudy phase transition above a certain temperature and the cloud point depended on the
incubation time in solution at room temperature. SANS and DLS studies showed that P1 formed clusters by
hydrophobic effect and weakened hydrophobic effect by polymer dissolution with incubation time consequently
attributed to decrease in size or disappearance of clusters. The temperature dependence of cluster formation can be
explained by hydrophobic effect with both the increase in scattering intensity by clusters at low q region and the
decrease in correlation length of polymer at high q region based on ‘two Lorentz model’ analysis. Decreasing
intensity of clusters on the scattering patterns of P1 with increasing incubation time shows weak cluster formation.
Porod exponent decreases from 2.5 to 2 for dilute P1 solution without clusters as incubation time increases, which
means dissolution change of P1 from mass fractal of branched polymer to loosen structure of polymer chains. These
results support that time dependent dissolution of P1 leads to the weakened hydrophobic effect.
ICNS 2013 International Conference on Neutron Scattering
P.132 Effects of citric acid on the diluted amphiphilic block copolymer system
H-M Lai1, K-C Shih1 and E Gilbert2
1
National Taiwan University, Taiwan, 2Bragg Institute (ANSTO), Australia
The structure of 5% Pluronic® (PL), an amphiphilic triblock copolymer composed of PEG (polyethylene glycol) PPG (polypropylene glycol) - PEG, in 0-24% w/v citric acid (CA) solution was studied using both small angle X-ray
and neutron scattering (SAXS/SANS). Scattering data suggest that PL forms cylindrical micelles of approximately 1
nm in radius and 8 nm in length at 24% CA. The chemical structure of CA, containing three carboxyl groups and one
hydroxyl group supports the formation of intermolecular hydrogen bonds with hydrophilic PEG segments of PL
micelles, resulting in the absorption or decoration of CA on the surface of cylindrical micelles. Indeed, the zeta
potential is found to change polarity (negative to positive) on the addition of CA to 5% PL solutions. In the absence
of CA, SAXS displayed a low q (< 0.01) power law decay suggesting the formation of large-scale PL micelles.
However, at 15% CA, this region was replaced by Guinier behaviour indicating PL dispersion. On increasing the CA
concentration further, to 24%, the Guinier region was, once again, replaced by a low q (< 0.01) power law decay.
Interestingly, when using solvent contrast variation SANS in which the CA has been contrast matched, the power-law
decay is absent indicating that these larger-scale structures are mediated by CA. This possibly occurs through salt
bridge-like structures between CA and PL micelles via hydrogen bonds.
P.133 Structural description of geopolymerization
P Steins1, A Poulesquen2, F Frizon2, O Diat3, J Causse3 and S Rossignol4
1
CEA, France, 2CEA MARCOULE DTCD/SPDE/LP2C, France, 3CEA/CNRS/UM2/ENSCM, Institut de Chimie Séparative
de Marcoule, Bagnols Sur Cèze, France, 4Ecole Nationale Supérieure de Céramique Industrielle – Limoges, France
Small Angle Neutron and X-ray Scattering (SANS, SAXS) techniques were used to study the polymerization rate of
geopolymers. Geopolymers are inorganic polymers synthetized by reaction of a strongly alkaline silicate solution
and an aluminosilicate source (metakaolin). The formation of geopolymer proceeds according to a mechanism of
dissolution/ restructuration/polymerisation leads to a consolidated material. Structural analysis through SAXS
experiments allowed the characterization of these mechanisms at the nano-scale. Several effects occur
simultaneously during geopolymerization: the dissolution of metakaolin resulting in the creation of monomers or
small oligomers in solution, and the reaction of these entities with the silicate species from the activating solution
leads to the gradual formation of the geopolymer network. The SANS technique was used to deconvolute these main
mechanisms during reaction. Indeed, the scattering intensity corresponding to the metakaolin was matched by
exchange of H2O-D2O mixture from the overall intensity measured over time. The results show that the scattering
intensity remains matched until the emergence of the percolating network of the geopolymer. The increase of the
intensity clearly demonstrates the densification of the porous network over time.
P.134 Slip and interface structure of polymer melts and solutions in contact with functionalized surfaces
K Theis-Bröhl1, P Gutfreund2, G Liesche1, A Dennison3, M Wolff3 and B Akgun4
1
University of Applied Sciences Bremerhaven, Germany, 2Institut Laue Langevin, France, 3Material Science,
Department of Physics, Uppsala University, Sweden, 4NIST Center for Neutron Research, USA
We present neutron and X-ray reflectometry (NR and XRR) studies on polystyrene (PS) sheared in contact with
functionalized solid surfaces. These methods provide a non-invasive tool to elucidate the structure of the buried
interface. We combine the scattering experiments with in situ non-linear rheology to gather information about the
microscopic origin of interfacial slip.We have performed in situ shear-NR on PS melts and solutions in contact with
ICNS 2013 International Conference on Neutron Scattering
chemically grafted PS chains. Entangled polymers can exhibit macroscopic slippage [1] and its origin is supposed
to arise from stretching of surface adsorbed chains and subsequent disentanglement from the free flowing chains
[2]. Although this model is well supported by tribology studies its final proof by direct structural observation is still
missing. The combination of surface sensitive rheometry in a plate-plate torsional shear set-up [3] and NR is
potentially a unique technique to address this question by using labeled polymer chains chemically attached to the
surface or in the free liquid. We present first results on in situ shear NR on PS melts in contact with high density PS
brushes as well as entangled PS solutions flowing over grafted PS chains of the same length in the mushroom
regime. In both cases we observe a structural change of the grafted PS at a certain shear rate that may be linked
to stretching and/or disentanglement of the interfacial chains.This work was supported by the Partnership for Soft
Cond. Matter and STINT (IG2011-2067) and VR (A0505501).
[1]
[2]
[3]
O. Bäumchen and K. Jacobs. J. Phys.: Cond. Matter 22, 033102 (2010)
A. Allal and B. Vergnes, J. Non-Newt. Fluid Mech. 164, 1 (2009)
J. Sanchez-Reyes and L. A. Archer, Langmuir 19, 3304 (2003)
P.135 Quasielastic neutron scattering study on the molecular dynamics of poly-alkyl-thiophenes
A Urbina1, A Guilbert2, J Abad1, T Seydel3, V García-Sakai4, C Díaz-Paniagua5, F Batallán6 and J Nelson2
1
Technical University of Cartagena, Spain, 2Imperial College London, UK, 3Institute Laue Langevin, France, 4ISIS
Spallation Source RAL-STFC,UK, 5MINECO, Spain, 6ICMM-CSIC, Spain
Conjugated polymers are the main components of a new generation of organic optoelectronic devices. Poly-alkylthiophenes (mainly P3HT) are the most broadly used active layers of plastic solar cells with good efficiency in power
conversion and are therefore considered the benchmark for comparison of other materials.
We present results of a quasielastic neutron scattering experiment on bulk samples of P3HT and P3OT on the
backscattering spectrometers IN10 and IN16 and on the time-of-flight spectrometer OSIRIS (ISIS-RAL). Within the
energy window available to the different instruments (exploring time scales from 20-90ps in OSIRIS and 3002000ps in IN10 and IN16) we have identified different molecular motions: from around 80K onwards, we observe
the onset of side group rotations, including methyl group rotations, on top of the typical Debye-Waller factor; this
motion is enclosed to a fixed cage, which from around 220K is opened; this motion, instead of a single well defined
characteristic time, shows a distribution of times that can be attributed to the disordered environment of the
molecules. At higher temperatures a slower motion that can be attributed to the onset of segmental motion (arelaxation) has been identified. This behaviour is similar to the one recently reported for poly-alkylene-oxides [1].
Fully atomistic molecular dynamic simulations have been performed on a model oligomer of P3HT and P3OT; the
simulations deliver values for the mean square displacement of the atoms of the side-chains which are compatible
with the measured values in all the range of temperatures up to 450K and gives an insight on the nature of the
molecular motions.
[1]
C. Gerstl et al., Macromolecules, 45, 4394 (2012)
P.136 Approaching a relation of surface slip and surface structure
M Wolff1, P Gutfreund2, O Bäumchen3, R Fetzer4 and K Jacobs4
1
Uppsala University, Sweden, 2Institut Laue-Langevin, France, 3McMaster University, Canada, 4Saarland University,
Germany
In recent years a discussion on the hydrodynamic boundary condition has been initiated and a deviation from the
non-slip boundary condition has been proven experimentally. Despite of the large number of studies a link of the
amount of slip to the surface properties on the sub-nm length scale is still missing.
ICNS 2013 International Conference on Neutron Scattering
As an example unentangled polystyrene (PS) melts show large slippage in contact with self-assembled-monolayers
(SAMs). Interestingly, in contact to octadecyl-trichlorosilane (OTS) and dodecyl-trichlorosilane (DTS) a huge
difference in slippage is found, even though both surfaces exhibit similar chemical and topological properties [1].
We present a combined neutron and X-ray reflectometry (NR and XRR) study on polystyrene (PS) in contact with
OTS and DTS surfaces. We show that the contacting PS segments order at the interface and we provide evidence
that the phenyl rings follow the tilt angle of the hydrocarbon tails which could be connected with the large slippage
difference observed [2].
[1]
[2]
R. Fetzer, K. Jacobs, A. Münch, B. Wagner, and T. P. Witelski. New slip regimes and the shape of dewetting
thin liquid films. Phys. Rev. Lett., 95(12): 127801, 2005.
P. Gutfreund, O. Bäumchen, R. Fetzer, D. van der Grinten, M. Maccarini, K. Jacobs, H. Zabel, and M. Wolff.
Solid surface structure affects liquid order at the polystyrene–self-assembled-monolayer interface. Phys.
Rev. E, 87: 012306, 2013.
P.137 SANS study for phase behaviors of polymeric ligands on the surface of janus Au NPs
M Yoo1, S Kim1, S-H Choi2 and J Bang1
1
Korea University, Korea, 2Hongik University, Korea
In recent, inorganic nanoparticles (NPs) have been investigated in various area such as photonic ban-gap materials,
sensors, and memory devices due to their fascinating features. Among the inorganic NPs, gold nanoparticles (Au
NPs) have a lot of interests due to their good accessibility to surface modification with various thiol terminated
polymeric ligands. For this reason Janus Au NPs can be easily synthesized via tuning the surface property of Au NPs
with two different ligands. In our previous works, we were successfully able to design and synthesize the thermally
stable Janus Au NPs with thiol terminated polystyrene (PS) and poly(methyl methacrylate) (PMMA). To characterize
the Janus properties of Au NPs, we introduced an indirect method which is the investigation of the location of Janus
Au NPs in lamellar forming PS-b-PMMA block copolymers. However, it is hard to confirm phase separation of the two
different ligands on the surface of Au NPs.
Herein, we prepared Janus Au NPs using deuterated PS (dPS) and PMMA, and normal Au NPs using dPS-r-PMMA
ligands which have various ligand lengths for small angle neutron scattering (SANS) study. As the ligands
characteristics are changed, the phase behaviors of the ligands on the surface of Au NPs are different. For example,
as the length of ligands on the Janus Au NPs is increased, phase separation of the ligands on the Janus Au NPs
should be clear. In this work, the phase separation of the ligands is systematically investigated using SANS.
P.138 SANS of dendritic copolymer solutions
S I Yun1, H Gi1, H Lee1 and M Huh2
1
Sangmyung University, Korea, 2Jeonju Institute of Machinery and Carbon Composites, Korea
Dendritic polymers have generated considerable research interest in nanotechnology due to their controllable
dimensions, topology, structure, and chemical functionality on the nanometric scale. This paper describes the
supramolecular assembly of arborescent(dendrigraft) copolymers in solution. The dendritic copolymers remained as
unimolecular (nonassociated) micelles in toluene at temperatures above the critical self-assembly temperature (cst)
but aggregated into supramolecular structures with a diameter of a few micrometers below the cst. Small-angle
neutron scattering (SANS) measurements in toluene revealed that the P2VP shell of the unimolecular micelles was
swollen above the cst. The supramolecular aggregates obtained below the cst had a spherical topology and a
relatively uniform size according to electron microscopy analysis. The temperature-responsive self-assembly process
was fully reversible. The cst varied with the polymer concentration and shifted to higher temperatures as the length
of the P2VP chains in the shell increased. The self-assembly mechanism reported provides a path to new types of
ICNS 2013 International Conference on Neutron Scattering
“smart” supramolecular structures. We also report the SANS studies on the aqueous solutions of dendrigraft
copolymers. The P2VP branches were quaternized with methyl iodide (CH3I) with a quaternization level of 60 %. The
quaternized P2VP dendrigraft copolymers dissolved well in water. SANS studies showed the structure of these
dendrigraft poolyelectrolyte and their self-assembly behavior in aqueous solutions.
ICNS 2013 International Conference on Neutron Scattering