Stimuli-Responsive Janus Particles:
Synthesis, Properties, Perspectives Towards Design of Smart Materials
Alla Synytska
Particles 2011-Berlin, A. Synytska
Leibniz Institute of Polymer Research Dresden, Germany
E-mail: synytska@ipfdd.de
What are the Janus Particles and their chronicle
“LET ME QUOTE STILL ANOTHER NEW ANIMAL: THE JANUS GRAINS …”
DE GENNES, NOBEL PRISE TALK 1991
Their chronicle …
Perro et al. 2005, A.H.E Müller et al. 2008
What are they good for …
http://www2.parc.com/hsl/projects/gyricon/
…Self-Assembly
Particles 2011-Berlin, A. Synytska
S. Granick et. al.
How can they be made …
(i) toposelective surface modification
(ii) dual-supplied spinning disk
(iv) Pickering
emulsion
(v) biphasic electrified jetting
(iii) micro fluidics
Particles 2011-Berlin, A. Synytska
A. Perro et. al., 2005
S. Granick et. al., 2006-2008
E. Kumacheva et.al., 2006
J. Lahann et. al., 2007
H. Kawaguchi et. al. 2007
etc…
Our Idea & Goal
We want to make them stimuli-responsive
Design of stimuli-responsive bicomponent polymer Janus
Particles (JPs) by “grafting from” / “grafting to“ approaches
Particles 2011-Berlin, A. Synytska
Synthesis of Janus particles
A. Synytska, et. al. Macromolecules 2008, 24, 9669
(highlighted in Science, 2008, 322, 1610)
Particles 2011-Berlin, A. Synytska
Immobilisation of initiator & polymer grafting
„Grafting-From“ Approach
via AGET-ATRP
„Grafting-To“ Approach
via amide formation
Br
NH
Br
SiO2
NH
pH, solvent, T, responsive..
Br
O
O
OH
O
fluorescein acrylate (FoAc)
λ ABS = 490 nm (blue)
O
Particles 2011-Berlin, A. Synytska
O
λ EM = 514 nm (green)
NH2
NH
200 nm, 1 µm
Preparation of colloidosomes
Size of colloidosomes : 50 – 200 µm
wax
SiO2
SiO2
Particles 2011-Berlin, A. Synytska
Preparation of colloidosomes
SiO2 / APS
Colloidosomes size: 20 – 100 µm
APS = 3-Aminopropyl
triethoxy silane
striking improvement of quality of SiO2/APS-wax
colloidosomes !!
Particles 2011-Berlin, A. Synytska
Preparation of colloidosomes
Unmodified native SiO2 particles
SiO2 particles modified with APS
SiO2 / APS
SiO2
2 µm
app. 10 - 15%, γSIO2 = 72 mJ/m2
γWAX = 32 mJ/m2
Particles 2011-Berlin, A. Synytska
500 nm
app. 21 - 25%, γAPS = 49 mJ/m2
Immobilisation of initiator
EDC, NHS
FTIR-ATR
Particles 2011-Berlin, A. Synytska
Poly-(tert butyl acrylate)-JPs
0.006
0.994
O
O
O
O
O
OH
O
O
1,0
SiO2 native
821 nm
Intensity, a.u.
SiO2 / PtBA - JPs
0,8
854 nm
0,6
0,4
0,2
0,0
100
1000
Rh, nm
Sample ID
Mn,
g/mol
PtBA-FoAc
184 000
Particles 2011-Berlin, A. Synytska
Mw,
g/mol
ThicknessPol
PDI
466 100 2.53
(TGA), nm
GDcompl. cov,
chains/nm2
GDJPs,
chains/nm2
37
0.17
0.68
A. Synytska, et. al. Macromolecules 2008, 24, 9669
10000
poly-(tert butyl acrylate)-JPs
Particles 2011-Berlin, A. Synytska
A. Synytska, et. al. Macromolecules 2008, 24, 9669
poly-(N-isopropylacrylamide)-JPs
O
N
∅SiO2 = 1µm
0.006
0.994
O
O
O
OH
O
O
Temperature-responsive and reversible swelling/shrinking of PNIPAAm-JPs
1,4
50°C
1209 nm - JPs
1,2
20°C
1246 nm - JPs
1135 nm - SiO2
1,0
0,8
0,6
0,4
0,2
0,0
100
Sample ID
Particles 2011-Berlin, A. Synytska
Mn,
g/mol
Mw,
g/mol
1000
ThicknessPol
PDI
PNIPAAm-FoAc 60 000 148 000 2.47
10000
Rh, [nm]
(TGA), nm
GDcompl. cov,
chains/nm2
GDJPs,
chains/nm2
22
0.22
0.88
poly-(N-isopropylacrylamide)-JPs
0.006
0.994
O
N
O
O
O
OH
Temperature-responsive and
reversible swelling/shrinking of
PNIPAAm-JPs
O
O
240
SiO2
PNIPAAm JP1
PNIPAAm F
Rh, nm
220
200
180
160
140
120
18
Particles 2011-Berlin, A. Synytska
20
22
24
26
28
30
32
Temperature,°C
34
36
38
Poly-(N-isopropylacrylamide) JPs
1
2
5 µm
1
200
intensity
150
100
50
0
20 µm
A. Synytska, et. al. Macromolecules 2008, 24, 9669
Particles 2011-Berlin, A. Synytska
5
10 15 20 25
distance, [pixel]
30
35
intensity
0
160
140
120
100
80
60
40
20
0
-20
2
0
5
10
15
20
25
distance, [pixel]
30
Grafting of second polymer by GT approach
poly (tert butyl acrylate)
poly (2-vinylpyridine)
O
O
O
O
HO
0.006
0.994
O
O
0.004
0.996
CN
OH
O
N
O
Mn = 8 450
Mw = 33 150
O
N
O
O
O
O
N
Particles 2011-Berlin, A. Synytska
+
rhodamine B-based comonomer
λEXC = 554 nm (green)
λ EM= 580 nm (red)
“Grafting to” of poly-(2-vinylpyridine)
Particles 2011-Berlin, A. Synytska
Sample ID
Mn,
g/mol
PtBA-FoAc
P2VP-Rh2
184 000
8 450
Mw,
g/mol
PDI
GM
466 100 2.53
33 150 3.92
GF
GT
ThPol
(TGA), nm
GDcompl. cov,
chains/nm2
GDJPs,
chains/nm2
37
9
0.17
0.10
0.68
0.40
Bi-functional oppositely charged polyelectrolyte - JPs
n
O
[H+]
O
Particles 2011-Berlin, A. Synytska
n
O
OH
Bi-functional Janus particles: Proof of “Janus Nature”
PtBA-FoAc-JPs
Particles 2011-Berlin, A. Synytska
P2VP-Rh2-JPs
PtBA/P2VP-Rh2-JPs
A. Synytska et. al., Macromolecules 2008 41 (24), 9669–9676
Bi-functional Janus particles: Proof of “Janus Nature”
Phase image
Phase image
Particles 2011-Berlin, A. Synytska
Stimulus-responsive clustering of Janus particles
Particles 2011-Berlin, A. Synytska
A. Synytska, et. al. Macromolecules 2008, 24, 9669
Stimulus-responsive clustering of Janus particles
Particles 2011-Berlin, A. Synytska
Macromolecules 2008, 24, 9669
Stimulus-responsive clustering of Janus particles
Electrosteric stabilized
doublets
Particles 2011-Berlin, A. Synytska
Application: Design of smart functional coatings..
Idea: using controlled aggregation/clustering of JPs for design of smart
materials with desired wetting properties
Ultrahydrophobic coatings!
Particles 2011-Berlin, A. Synytska
A. Synytska, et. al. Adv. Func. Mat. 2011,
21 (12), 2338-2344
Application: modification of textiles with Janus particles
Controlling the pore size, barrier textiles..
O
O
O
A. Synytska, et. al. ACS Appl. Mater. Interfaces 2011, 3, 1216–1220
Particles 2011-Berlin, A. Synytska
Wettability of textiles with Janus particles
Particles 2011-Berlin, A. Synytska
A. Synytska, et. al. ACS Appl. Mater. Interfaces 2011, 3, 1216–1220
Application: Stabilization of emulsions..
HD/W
Particles 2011-Berlin, A. Synytska
HD/JPs/W
A. Synytska et. al., in preparation
Summary
Particles 2011-Berlin, A. Synytska
Acknowledgments
Acknowledgments
k in
d
fo
ry
ou
r
Th
an
ks
S. Berger (IPF)
E. Svetushkina (IPF)
N. Puretskiy (IPF)
G. Stoychev (IPF)
C. Hase (IPF)
L. Schellkopf (IPF)
L. Ionov (IPF)
K-J. Eichhorn (IPF)
S. Diez (MPI-CBG)
M. Stamm (IPF)
at
te
nt
io
n
!
Thanks to
DFG and IPF..for
financial
. and
yousupport
for kind attention!