Composite Silica:Polypeptide Colloidal Particles
Paul S. Russo
Macromolecular Studies Group
Louisiana State University
Materials Science & Engineering Department
North Carolina State University
Friday, November 9
Generic Outline Slide
Thank hosts for inviting me
Tell jokes
Why is the research interesting?
(if not interesting, at least important)
Background material
Plan of attack (hypothesis/testing)
Results
Discussion/Conclusion
Questions
Self-recrimination
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French Air Force
Vive l’audacite!
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Been Deployed
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Minnesota National Guard
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Fuzzballs
a silica interior and synthetic
homopolypeptide exterior.
Silica (SiO2) core
typically 200 nm diameter
Homopolypeptide Shell
typically 100 nm thick
Why?
The usual reasons for polymer-coated particles
 Stability studies, probe diffusion, standards, etc.
The better reasons for polypeptide-coated particles
 Should allow excellent shell thickness control.
 Shell is rigid spacer for assembling silica spheres.
 Astounding chemical versatility and functionality, including
chirality.
 Responsiveness and perfection of structures through
reproducible helix-coil transitions.
Making the Particles
 Picture is for a shell of
PBLG = poly(benzyl
glutamate)
[NH-CHR’-CO]x with
R’=(CH2)2COOBz
H2N
(H3CO)3 Si
NH2
O
HO
O
O
Si
OH
O
Si
O
NH2
 Other shells so far
PCBL=
poly(carbobenzoxy-Llysine)
R’=(CH2)4NHCOOBz
Si
O
Si
O
OH
HO
NH2
O
O
O
RO
O
NH
NH
NH
NH
N
H O
R = Benzyl
NH2
Is the shell covalently attached?
s our ce : stob ers IR
so urce: bf2cp 33 IR
s ou rc e: b f5 ttIR p1 48
16
(a)
14
(b)
14
10
1628
8
6
802
4
946
2
stober
8
10
8
Transmittance / %
Transmittance / %
Transmittance / %
10
1551
1736
1653
6
PBLG-coated silica
3500
3000
2500
6
1391
4
1654
DMF
Washed
2
4
0
-2
4000
(c)
12
12
2000
1500
1000
Wavenumber / cm-1
500
Figure 2a
Fong and Russo
2
4000
3500
3000
2500
2000
Wavenumber / cm-1
0
1500
1000
500
Figure 2b
Fong and Russo
4000
3500
3000
2500
2000
1500
Wavenumber / cm-1
Almost certainly
(By the way, the polypeptide conformation is mostly
a-helix with some b-sheet)
1000
500
Figure 2c
Fong and Russo
TGA/DTA
0
Silica Spheres Alone
Mixed with 16K and 91K
-20
TG / %
PBLG, then isolated (2 curves)
Composite Particle
-40
-60
-80
PBLG
-100
0
200
400
600
T/
800
1000
1200
oC
Fong and Russo
Figure 3
--Particles with ~ 23% by mass PBLG
--Again, no evidence for binding of loose PBLG
Dynamic Light Scattering
R = 990
5.0
h
4.0
Silica Spheres
C H Spheres
3.5
18
37
Composite Particles
3.0
D
app
/ 10-8cm2s-1
4.5
2.5
R = 973
h
2.0
1.5
R = 1750
h
1.0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
q2/1010 cm-2
Bigger ones may diffuse slower (solvent viscosity effects)
Flat plots indicate excellent, latex-like uniformity
Particle Characteristics
 Silica Core Properties



Radius from DLS: 97 nm
Molar Mass: 4.5 x 109
Surface area: 15.6 m2/g
 PBLG Shell Properties



78 nm.
~90% solvent / 10% polymer.
Polymer density limited by crowding around initiator
sites.
Shell thickness not controlled by [M]/[I]
--Not all initiators are active: crowding.
--Controlling and assaying initiator density are ongoing
challenges.
--Attachment of ready-made polymers to surfaces
increasingly appealing.
Conclusions
 Facile synthesis of composite silica/homopolypeptide
core/shell organophilic particles.
 Excellent uniformity.
 Shell highly solvated.
 Nonionic colloidal crystals that may prove amenable to
control via conformational transitions.
 Potential applications include optical devices, stationary
phases for chiral separation and model particles for studies
of polymer/colloid interactions.
 Polypeptide chemistry allows almost infinite variation.
 Much development remains to be done. In particular,
thickness is not yet easily controllable.
Colloidal Crystals (PCBL Shell)
Why Study?
~ 2 mm
~ 0.5 m
SiO2
Beautiful!
Fun supramolecular synthesize &
characterize from nm to mm.
Sufficiently
dense devices,
suspensions
Applies to optical
assemble
colloidal
crystals.paint,
betterinto
lasers,
pigment-free
With“smart
a sizecolloids”,
that matches
that muscle,
of
artificial
visible light, diffraction results.
separations technology
Domains with different
orientations result in different
and quite pure colors.
Helical homopolypeptide shell
Transmittance measured on monochromatorequipped microscope
3.5
Transmitted Light Intensity vs. Wavelength
PCBL/Silica Composite Particle
3.0
Imaged region includes 3 domains
568 nm
2.5
I
2.0
593 nm
615 nm
1.5
1.0
0.5
0.0
400
500
600
700
/nm
FWHM of line is ~ 16 nm, comparable to
typical interference filters of conventional design
Achieving population inversion gets
progressively harder for shorter
wavelengths; green < red.
E2
A12
B12
E1


B12 

A12 8
3
Modulation FPR Device
PA
TA/PVD
PMT
*
OS
*
D
S
*
M
DM
OBJ
RR
*
M
L
AOM
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10-7
10-6
10-5
10-4
10-3
10-2
4.0
0.5
3.5
Before Sonication
Amplitude/arbitrary
3.0
2.5
0.0
2.0
1.5
-0.5
1.0
After Sonication
0.5
0.0
-1.0
10-7
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10-6
10-5
10-4
R /cm
h
10-3
10-2
N
Silica
coating
Surface
Functionalization
N
N
N
N
N
N
N
NCA-monomer
N
N
N
N
N
N
N
N
N
N
N
N
N
N
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crosslinking
N
N
N
N
N
N
Fuzzballs: nm to mm
vis
Helical polypeptides
SiO2
Colloidal crystal
•diffract visible light
•ours will be smart!
Colloidal chain
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•chiral stationary phase?
•can they swim?
•Can they be hollow?
What label should we put on this
science and those who do it?
 Reviewer of a recent paper said it was synthetic.
 If so, then it’s MacroSynthetic--our monomer has
M ~ 109 g/mol.
 Characterization requires some physical concepts.
 It borrows heavily from biology: a-helical design
and transitions to other conformations.
 Applications are materials-oriented.
 So….the person who does this is a jack of all
trades, master of some. He or she is employable!
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Thanks for your hospitality
“The work of the righteous is done by others.”
--God
Sibel Turksen – still with me
Brian Fong – Buckey Technologies, Memphis
Wieslaw Stryjewski – Resident Equipment Guru
National Science Foundation
American
Chemical Society
6/27/2016
Observe! Wonder! Have Fun!
Current Grad Students
•Garrett Doucet
•Randy Cush
•Sibel Turksen
•Rongjuan Cong
Collaborators
•George Newkome
•Greg Baker
•Chuck Moorefield
•Duen-wu Hua
6/27/2016
Current Postdocs
•???
•???
•???
Current Undergrads
•Jonathan Strange
•Martinique Perkins
•Rae-lynne Poirrier
Ph.D. Alumni
NAME
YEAR
WORKS AT
WHERE
1989
PAPERS
PUBLISHED
4
Mark DeLong
Union Carbide
Mazidah
Mustafa
Zimei Bu
1990
3
Housewife
S. Charleston
WV
Detroit, MI
1994
6
Yale & NIST
NH & DC
Debbie Tipton
1995
3
Chevron
Orange, TX
Daewon Sohn
1995
6
Seoul, Korea
Keunok Yu
1995
3
Lucille SmithWright
1999
2+
Han-Yang
University
Kunsan
Universisty
USGS
6/27/2016
Kunsan, Korea
Baton Rouge
Collaborations
 At LSU






Hammer/McCarley/McLaughlin
Daly/Negulescu
Bricker
Strongin
Soper
Thomas
 Visitors from other places (not including industry!)







6/27/2016
METU--Ankara, Turkey (Kucukyavuz)
Indiana-Purdue University (Dubin)
Georgia Tech (Srinivasarao)
U. South Florida (Newkome)
Minnesota (Bloomfield)
NIST (Amis)
Han-yang--Korea (Sohn)
Reversibly Freezing in LC transitions
Melt—note colors & lines
Frozen LC—some other
structure appears, but the
lines are still present.
6/27/2016
Gels form faster at lower
temperatures and lower M’s
sarah file: s.formmw
sarah file: s.form
100
PSLG-129
90
PSLG-214
15oC
80
PSLG-28
25
10oC
70
60
Time (seconds)
Time (seconds)
at 15oC
30
20oC
50
40
30
20
15
10
20
5
10
0
0
0
2
4
6
Weight % PSLG
6/27/2016
8
10
Schmidtke et al.
Figure 2a
9
10
11
12
13
Weight % PSLG
14
15
Schmidtke et al.
Figure 2b
H2N
(H3CO)3 Si
Si
O
Si
O
OH
HO
NH2
O
NH2
O
HO
O
O
Si
OH
O
Si
O
NH2
O
O
RO
O
NH
NH
NH
NH
N
H O
R = Benzyl
6/27/2016
NH2
source: bf1xy2c
R = 990
h
5.0
D
app
/ 10-8cm2s-1
4.5
4.0
Silica Spheres
C H
3.5
18 37
Composite Particles
3.0
2.5
R = 973
h
2.0
1.5
R = 1750
h
1.0
1.0
1.5
2.0
2.5
q2/1010 cm-2
6/27/2016
3.0
3.5
4.0
Figure 4
Fong and Russo
Core
Radius from DLS = Rc
Mass
MW
Number of particles / gram
Surface area / particle
Surface area / gram
970 Å
7.48 x 10-15 g
4.50 x 10+9 g/mol
1.33 x 10+14
1.18 x 10+7 Å2
1.56 x 10+21 Å2/g =
15.6 m2/g
PBLG Shell
Radius from DLS
Thickness from DLS = t
Volume
Calculated mass assuming solid PBLG,
=1.26 g/mL
Mass according to TGA
Apparent PBLG weight % in solvated shell
Expected shell thickness assuming effective
number of initiators follows Eq. 9
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1750 Å
780 Å
(i.e., 1750 Å-970 Å)
1.86 x 10-14 cm3
2.35 x 10-14 g
2.23 x 10-15 g
9.5 %
11,500 Å
Hierarchical Structures Containing
Composite
Magnetic- Silica-Homopolypeptide
Colloidal Particles
Research Progress
Part A
Sibel Türkşen
Louisiana State University
Department of Chemistry,
Baton Rouge,
2001
6/27/2016
Outline
 Introduction




Purpose
What has been done?
What we did?
Why?
 Background



Stöber spheres
Silica-homopolypeptide particles
Magnetic inclusions
 Results
 Conclusion
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Purpose
 Synthesize new composite core shell
particles
 Characterization
 Investigate amorphous-crystalline, helixcoil transitions
 Applications




Biosensors
Artificial muscles
Optical devices
Separation and analysis of biomolecules
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Previous Studies




Colloid polymer interactions
Stability of particles
PS, PMMA, PEO attached to colloids
Tsubokawa et al.

coated carbon black
 Dietz et al.

fumed silica
 Russo et al.

colloidal silica
6/27/2016
This project
 Homopolypeptides as organophilic coatings
 Combining superparamagnetic ability with
responsiveness
 Using magnetic ability to make responsive
chains
 Crystalline colloids
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Generally...
 Most polymer colloids
use boring,
unstructured, random
coil polymers
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Particle Preparation
Silica
coating
Surface
Functionalization
N
N
N
N
N
N
N
N
NCA-monomer
N
N
N
N
N
N
N
N
N
N
N
N
N
N
6/27/2016
crosslinking
N
N
N
N
N
N
6/27/2016
N
N
N
N
N
N
N
N
N
N
N
N
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N
N
N
N
COIL
N
N
N
N
N
HELIX
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Superparamagnets
 Fluid properties of a liquid
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 Magnetic properties of a solid
Synthesis of Magnetic Particles
2 FeCl3 + FeCl2 + 8 NH4OH
Fe3O4 + 8 NH4Cl
+
N
-OH
-OH
-OH
Fe3O4
-OH
-OH
6/27/2016
+
-OH
CH3OH
H3C
N CH
3
CH3
TMA
tetramethylammonium hydroxide
+
OH-
N -OH
+ -OH
Fe3O4
N
OH-+
N
+
N
OH-
OH-
+
N
Colloidal Silica
 Silica dispersion in liquid medium
 Monodispersed spheres
 Refractive index match with non-polar
liquids
 Effective coating
 Allow further coating
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Homopolypeptides
HN
H
C
O
 PBLG
C
R
n



R = CH2CH2CO2CH2C6H5
for PBLG
R =(CH2)4NHCO2CH2C6H5
for PCBL
6/27/2016
best understood
homopolypeptide
persistent structure
helix-coil transition
 PCBL

helix-coil transition @
27 C in m-cresol
Why homopolypeptides?
 Controllable and narrowly distributed size
 High viscosity @ low conc.
 Well defined secondary structures
 Responsiveness
 Chiral nature
6/27/2016
SEM & FTIR Results for Stöbers
Stober spheres
1925
60
660
40
885
1096
2985
0
1420
20
3336
Percent Transmittance
80
4000 3500 3000 2500 2000 1500 1000
Wavenumber / cm-1
6/27/2016
500
TEM Results
Dark:Magnetic inclusions
(~ 10nm)
Gray:Glassy SiO2 matrix
Magnetic silica particles
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DLS Results
0.30
0.25
Magnetic Silica Particles
0.15
R
app
/ m
0.20
0.10
Magnetic Particles
0.05
0.00
6/27/2016
0.064  Latex spheres
0
1
2
3
4
5
q2 / 1010 cm -1
6
7
8
TGA Results
27.3 oC
100
98.75 %
212.47 oC
3.5
Weight ( % )
80
3.0
2.5
296.77
60
oC
56.25 %
2.0
1.5
40
246.14 oC
1.009 % / oC
304.56 oC
0.6003 % / oC
20
395.58 oC
Weight percentage
1.0
742.14 oC
0.5
12.32 %
Derivative of weight percentage
0.0
0
0
100
200
300
400
500
600
700
Temperature ( oC )
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Magnetic-silica-homopolypeptide composite particles
800
Deriv. Weight ( % / oC )
100.0 %
4.0
150.05 oC
Colloidal crystal
Silica-homopolypeptide composite colloidal crystal
6/27/2016
Conclusion
 First goal is achieved
• Magnetic-silica-homopolypeptide composite
particles
 Responsiveness
• Promising results
 Well-defined
 Multiple applications
 Hierarchical particles
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Future Studies




Prove the responsive character of the particles
Crosslinking via Grubbs’ catalyst
Make the chains
Investigate colloidal crystal structures
6/27/2016
Acknowledgment




Paul Russo
Our research group
ACS
Special thanks to…




Garrett
Cong
Kem
Yilmaz, Selen & Murat...
6/27/2016
Stöber Synthesis
OC2H5
H5C2O
C2H5OH
Si
OC2H5
OC2H5
H5C2O
NH4OH
OC2H5
OC2H5
Si
Si
O
OC2H5
OC2H5
OC2H5
TEOS
OH
HO
TEOS
Hydrolysis
C2H5OH
NH4OH
OH
Si O Si
HO
O
Si O
O
Si
HO
OH
OH
OH
HO
O
HO
OH
OH
Stober Spheres
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Silylation Reaction
6/27/2016
EM 6945
60 cm 200.0 KV
This was on my poster ,TEM of magnetic silica
particles, I have more of these in the microscopy
computer under users/sibel
6/27/2016
These are from the poster too.Since you
have the video I think you won’t need them
but in case
6/27/2016