Regensburg 2004 – scientific programme

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.69: Poster

Friday, March 12, 2004, 10:30–13:00, B

A cluster mode–coupling approach to weak gelation in colloids and proteins — •Klaus Kroy — Hahn-Meitner Institut, Berlin

Mode–coupling theory (MCT) predicts arrest of colloids in terms of their volume fraction, and the range and depth of the interparticle attraction. We discuss how effective values of these parameters evolve under cluster aggregation. We argue that weak gelation in colloids and proteins can be idealized as a two–stage ergodicity breaking: first at short scales (approximated by the bare MCT) and then at larger scales (governed by MCT applied to clusters). The competition between arrest and phase separation is considered in relation to recent experiments with colloids and proteins. Among other things we predict a long–lived ‘semi–ergodic’ phase of mobile clusters, a ‘kinked’ gel line, and strong stretching of the relaxation even at low volume fractions.

(Work done in collaboration with the soft condensed matter group of the University of Edinburgh, see cond-mat/0310566,0309616)