Soft Matter

Group philosophyDefine projects, complimentarity, mobility and international collaborations,visitors, group meetings, fundingInfrastructure with expertise (basis for further development)

Members (senior)G. FytasG. Petekidis D. Vlassopoulos

FORTH people:A. Larsen, technicianU. Jonas, Researcher AB. Loppinet, Researcher B

Current funding: EU (ITN, NoE, LSI), limited industrial

Collaborations: US, Canada, Japan, Korea, France, UK, Germany, Belgium

Tailoring the flow of soft matter molecular design: synergy of chemistry, modeling, physical

expt

HardSoft

Com

ple

xit

y -

tu

nab

ility

ThermodynamicsDynamic arrest

Structure / dynamicsRheology

D. Vlassopoulos UoC-MST & FORTH-IESL

Viscoelasticity of entangled polymers

polymers with free ends

State-of-the-art: from Edwards over deGennes to Doi and McLeish

Tube modelPlateau modulus G=ρRT/Me

Linear: reptation etcStar: arm retraction

Viscoelasticity of entangled polymers

polymers with free ends

State-of-the-art: from Edwards over deGennes to Doi and McLeish

Q: polymers without free ends ?

Tube modelPlateau modulus G=ρRT/Me

Linear: reptation etcStar: arm retraction

Ring polymers

Roovers, NRC, 1985

Pure linear melt and melt of ring PS (no plateau)

τe

0.43

Power-law stress relaxation of entangled rings

Kapnistos et al, Nat. Mat. 2008

M. Rubinstein, UNC, 2003

Key: Critical fractionation toobtain pure rings(T. Chang, Pohang Univ., 2000)

t [s]

0.0001 0.001 0.01 0.1 1 10 100 1000

G(t

) [P

a]

1e+0

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

1e+7

ring 81kG(t) prediction rubinstein 81kring 38kG(t) prediction rubinstein 38kring 24kG(t) prediction rubinstein 24k

R. Pasquino

Linear ‘contaminant’ chainpenetrates rings maximizingentropy and percolating

New PI rings 24, 38, 81 K: Hadjichristidis et al, Univ. Athens

van Megen and Underwood, PRE 1994

Colloidal Glasses

Mason, Weitz, PRL, 1995

State-of-the-art: HS from Pusey over Götsche to Cates-Fuchs-Weitz

van Megen and Underwood, PRE 1994

Colloidal Glasses

Mason, Weitz, PRL, 1995

State-of-the-art: HS from Pusey over Götsche to Cates-Fuchs-Weitz

Q: effects of softness, particle architecture

Star polymers

Roovers, Hadjichristidis, 1993Gauthier, U. Waterloo, 2007

Binary star mixtures

Single glass Double glass

Asymmetric glass

Attractiveglass

Liquid(Ergodic)

C2

Single glass Double glass

Asymmetric glass

Attractiveglass

Liquid(Ergodic)

C2

Scale with softness S=δf/Na

with Stiakakis, Erwin, Cloitre, JCPM 2011

with Mayer, Stiakakis, Likos, Zaccarelli, Sciortino, Nat. Mat. 2008

10-6 10-4 10-2 100 102

100

101

102

103

[P

a]

[s-1].

1.0

Single star glass flow

Key: interpenetrability

П~R/√f

Rogers et al, PRL 2008

with B.Erwin,

M. CloitreJOR 2010, SM 2010PRE 2011

Cloitre

G. G. FullerC. F. Brooks et al., Langmuir, 1999, 15, 2450

ISR: Interfacial Stress Rheometer

Interfacial Rheology and Dynamics

State-of-the-art: from Gibbs-Langmuir over Plateau to Fuller-Vermant

Q: tailor film rheology (molecular design), ‘transfer’ 3D problems to 2D

G. G. FullerC. F. Brooks et al., Langmuir, 1999, 15, 2450

ISR: Interfacial Stress Rheometer

Interfacial Rheology and Dynamics

State-of-the-art: from Gibbs-Langmuir over Plateau to Fuller-Vermant

Q: tailor film rheology (molecular design), ‘transfer’ 3D problems to 2D

25 30 35 40 45 500

4

8

12

16

20

31 32 33 34 35

2

4

(m

N m

-1)

A (Å molecule-1)

F12H12 F11H1-core-H12 F12H20

(m

N m

-1)

A (Å2 molecule-1)

T = 20 °C

transition

0.1 1 10

0.1

1

T = 20 °C

G''

G'

G',

G''

(mN

m-1

)

f (rad s-1)

10 mN m-1

8 mN m-1

6 mN m-1

4 mN m-1

2 mN m-1

F12H12

fluorocarbon diblocks

colloidal particles

L. deViguerie, C. Christopoulou, C. Klein, R. Berger, C. Clark, K. Muellen, N. Vogel, K. Landfester and U. Jonas