Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 1: DRG-DPG SYMPOSIUM Rheology I

CPP 1.6: Talk

Monday, February 25, 2008, 11:30–11:45, C 130

Nonlinear rheology of a glassy solution of semiflexible polymers — •Jens Glaser¹, Christian Hubert¹, and Klaus Kroy^1,2 — ¹Inst. f. Theoretische Physik, Universität Leipzig, PF 100920, 04009 Leipzig — ²Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin,

Recent experimental studies on purified solutions of the semiflexible biopolymer F-actin show a pronounced transition from shear softening to shear stiffening behavior as a function of different physiological parameters. The results suggest a surprising invariance of the rheology of the F-actin solution with respect to the choice of the control parameter. We rationalize this property in terms of the recently introduced glassy wormlike chain (GWLC) model, where the nonlinear response is traced back to a strong stretching of the relaxation spectrum of an ordinary wormlike chain, quantified by a single stretching parameter which is the height of free energy barriers slowing down the relaxation of the polymer. Predictions for the maximum strain of the network, apparent power-law stiffening exponents and analytical results are given. The relation of the stretching parameter to changes in the physiological parameters is discussed.

[1] Semmrich C, Storz T, Glaser J, Merkel R, Bausch, A. R, Kroy K, Proc Natl Acad Sci USA, In Press (2007)
[2] arXiv:0705.0490, arXiv:0711:2427