Physico-chimie des Polymères et des Milieux Dispersés
Photosensitive complexes of hydrophobically modified polymers,
micelles of surfactants and enzymes.
Juliette RUCHMANN, ESPCI, Paris, France
Macro 2008, Taipei, June 29 - July 4
2
Stimuli-responsive systems of polymer and surfactant
protein refolding
sol/gel transition
Polymer hydrophilic/ hydrophobic
stimuli: pH, T°, light …
understanding of the interaction between polymer and surfactant
association polymer / surfactantmultiple applications
3
Light-stimulated association
photo-polymer + non responsive surfactant macroscopic response to light study of physico-chemical parameters
h non invasive and focused stimuli
4
Azobenzene-modified polymer
UV : 365 nm
blue : 436 nm
Irradiation
cis
trans
HN O O O
(CH2)5
NHO
NN
x 100-x
HN O O O
(CH2)5
NHO
NN
x 100-x chain length (Mn)small: 7,500 g/mollong: 42,000 g/mol or 60,000 g/mol
amount of modificationx = 1 - 5%
NMR spectroscopy UV-visible
Structural parameters
42_3.5C6azo
x = 3.5% / Mn=42,000g/mol
SurfactantTX 100
O
C8H17
OH9-10
5
700
600
500
400
300
200
100
0
Inte
nsi
ty
700
600
500
400
300
200
100
0
Inte
nsi
ty
700
600
500
400
300
200
100
0
Inte
nsi
ty
Light-responsive complexesStatic light scattering
1/ mixture =complexes formation
reversible photo-association / photo-dissociation
several cycles for hoursJ. Ruchmann, S. Fouilloux, C. Tribet, Soft Matter, in press
TX
10
0
42
_3.5
C6
azo
1 2
UVlight
Bluelightin the
dark
mix
ture
3
2/ UV light =partial
photo-dissociation
3/ Blue light =re-association
(A.U .)
6
Light-responsive complexes
trans azobenzene (100% black / 80% blue)
= hydrophobicity maximum
Black / Blue
association with lipophilic core of the micelles
cis azobenzene (80% UV)
= more polar form
UV
decrease of the affinity for the micelles
blue(436nm)
UV (365nm)
7
Transfer of the azobenzene from water
into the micelles
1.0
0.5
0 A
bso
rbance
(D
.O.)
500450400350300
Wavelength (nm)
ΔAbs
42_3.5C6azo
42_3.5C6azo with TX100
5x10-3
4
3
2
1
0
Abs/
[azo] (µ
M-1)
1.00.80.60.40.20
[TX 100]total (g/ L)
bound azobenzene
TOT[azo]BOUND[azo]
ATOT[azo]
AbsΔτ
UV visible spectrophotometry
(O.D
.)
8
Necklace composition
continuous injection bound surfactants
Abso
rbance
1000900800700600500Time (s)
neutral reference
TX100(neutral)
complexes(anionic)
2.5
2.0
1.5
1.0
0.5
0TX 1
00
bound/p
oly
mer
(g/g
)1.00.80.60.40.20
[TX 100]free (g/ L)
Electrophoresis
binding isotherm
9
3 regimes of association5x10
-3
4
3
2
1
0
A
bs/[
azo] (µ
M-1)
0.80.60.40.20
[TX 100]free (g/ L)
2.5
2.0
1.5
1.0
0.5
0
TX 1
00
bound /p
oly
mer (g
/g)
1 2 3
no association
anti-cooperative
binding
TX100 bound
azo bound<< 1
tight association
TX100 bound
azo bound# 1
bound surfactants
bound azobenzene
s
cmc
10
2.5
2.0
1.5
1.0
0.5
0
TX 1
00
bound/p
oly
mer
(g/g
)
1.00.80.60.40.20
[TX 100]free (g/ L)
Light-responsive complexes
light-response in a large range of compositions
Electrophoresis
blue irradiationUV irradiation
42_5C6azo
60% dissociation
2 3
h
black/blue
UV
h
black/blue
UV
11
2.5
2.0
1.5
1.0
0.5
01.00.80.60.40.20
2.5
2.0
1.5
1.0
0.5
01.00.80.60.40.20
2.5
2.0
1.5
1.0
0.5
01.00.80.60.40.20
Influence of different parameters
7.5_4C6azo
TX
100
bou
nd/p
oly
mer
(g/g
)
[TX 100]free (g/L) [TX 100]free (g/L)
30% photo-
dissociation
small chain length
70% photo-dissociation
low ionic strength1% modification
almost no association42_1C6azo
42_5C6azo
2.5
2.0
1.5
1.0
0.5
01.00.80.60.40.20
42_5C6azo
60% photo-dissociation
12
Applications
AMPs + neutral surfactants reversible photo-control of emulsion S. Khoukh, et al., Chemphyschem, 2005. 6(10), 2009-2012
J. Ruchmann, S. Fouilloux, C. Tribet, Soft Matter, in press
h
AMPs + protein (BSA) photo-responsive physical gels
h
G. Pouliquen and C. Tribet, Macromolecules, 2006. 39(1), 373-383
13
AMPs + enzyme (BCA)
Protein refolding
unfolded protein
refolded
protein
REFO
LD
ING
soluble complexes
+
no aggregation
association
dissociation
14
50
40
30
20
10
0 Inte
nsi
ty (A
.U.)
100806040200
Time (min)
Protein refolding
no quenching
+ +
quenching
dissociation
associationFlu
ore
scen
ce
Physico-chimie des Polymères et des Milieux Dispersés
Acknowledgements Christophe TRIBET
Agnès PALLIER
Sarah FOUILLOUXANR-06-BLAN-0174 and BLAN07-3_190727
French ministery of research
CONCLUSION
photo-control of association/dissociation with micelles and more generally with
hydrophobic colloids (proteins …)
16
3 regimes1 32
h hh
cmc
17
Association with surfactants1.0
0.5
0
Inte
nsi
ty (a.u
.)
0.1 1 10 100 1000
Hydrodymanic Radius (nm)
TX 100
42_3.5C6azo
mixture
Rh(complexes) ≈ Rh(polymer isolated chains)
Rh(complexes)BLACK ≈ Rh(complexes)UV well define complexes no aggregation
SurfactantTX 100
O
C8H17
OH9-10
18
AMP multiple association onto an hydrophobic cluster.
Kass TΔSloop + ΔGazo < 0
balance between : - loop free energy - free energy of transfer of azobenzene between water and the micelle