Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: POSTERS Single Molecules, Biopolymers, Membranes

CPP 9.17: Poster

Montag, 25. Februar 2008, 16:45–19:00, Poster A

Nonlinear rheology of a glassy solution of semiflexible polymers — •Christian Hubert¹, Jens Glaser¹, and Klaus Kroy^1,2 — ¹ITP,Universität Leipzig, PF 100920,04009 Leipzig — ²HMI,Glienicker Str. 100, 14109 Berlin

Recent experimental studies on purified solutions of the semiflexible biopolymer F-actin show a pronounced transition of 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. This property is successfully explained by 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. The model incorporates two stretching parameters corresponding to the height of free energy barriers due to stickiness and steric (free volume) interactions respectively, slowing down the relaxation of the polymer. A comprehensive overview of the dependence of the stretching parameters and the shear modulus on the physiological parameters is given.

[1] Semmrich, Storz, Glaser, Merkel, Bausch, Kroy,

PNAS, In Press (2007)

[2] arXiv: 0705.0490, arXiv: 0711.2427