Regensburg 2002 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.38: Poster

Donnerstag, 14. März 2002, 15:30–18:00, D

Diffusion and thermal diffusion of semidilute to concentrated solutions of polystyrene in toluene in the vicinity of the glass transition — •Jürgen Rauch and Werner Köhler — Physikalisches Institut, Universität Bayreuth, 95448 Bayreuth, Germany

The approaching glass transition in polystyrene/toluene solutions leads to a sharp decay of both the collective diffusion coefficient D and the thermal diffusion coefficient D_T at concentrations above 0.2 g/cm³. The Soret coefficient S_T = D_T/D follows power law scaling from semidilute to concentrated and is not influenced by the slowing down of the dynamics associated with the glass transition. Both D and D_T are governed by the same friction coefficient. The scaling behavior of S_T with concentration on approach of the glass transition is compared to the divergence of S_T near a consolute critical point. A transformation of the concentration dependence of D_T to the reduced temperature (T−T_g)/T_g yields a power law dependence of D_T.