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