Soft Matter Group philosophy Define projects, complimentarity, mobility and international collaborations, visitors, group meetings, funding Infrastructure with expertise (basis for further development) Members (senior) G. Fytas G. Petekidis D. Vlassopoulos FORTH people: A.Larsen, technician U. Jonas, Researcher A B. 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 Complexity - tunability Thermodynamics Dynamic arrest Structure / dynamics Rheology 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 model Plateau modulus G=ρRT/Me Linear: reptation etc Star: 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 model Plateau modulus G=ρRT/Me Linear: reptation etc Star: arm retraction Ring polymers Roovers, NRC, 1985
Pure linear melt and melt of ring PS (no plateau) τeτe 0.43 Power-law stress relaxation of entangled rings Kapnistos et al, Nat. Mat M. Rubinstein, UNC, 2003 Key: Critical fractionation to obtain pure rings ( T. Chang, Pohang Univ., 2000) R. Pasquino Linear ‘contaminant’ chain penetrates rings maximizing entropy 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, 1993 Gauthier, U. Waterloo, 2007
Binary star mixtures Scale with softness S=δf/Na with Stiakakis, Erwin, Cloitre, JCPM 2011 with Mayer, Stiakakis, Likos, Zaccarelli, Sciortino, Nat. Mat Single star glass flow Key: interpenetrability П~R/√f Rogers et al, PRL 2008 with B.Erwin, M. Cloitre JOR 2010, SM 2010 PRE 2011 Cloitre
G. G. Fuller C. 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. Fuller C. 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 fluorocarbon diblocks colloidal particles L. deViguerie, C. Christopoulou, C. Klein, R. Berger, C. Clark, K. Muellen, N. Vogel, K. Landfester and U. Jonas