Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 8: SYMPOSIUM Nonequilibrium Phenomena in Soft-Condensed Matter
CPP 8.7: Vortrag
Dienstag, 28. März 2006, 15:45–16:00, ZEU Lich
Transport coefficients of polymer solutions and blends near a glass and a liquid-liquid phase transition — •Werner Köhler, Albert Voit, Jürgen Rauch, and Alexei Krekhov — Physikalisches Institut, Universität Bayreuth
Transport coefficients in polymer solutions and blends can usually be written in terms of a thermodynamic (osmotic modulus) and a kinetic (friction) factor. We discuss self diffusion, collective diffusion, and thermal diffusion of dilute to concentrated polymer solutions and polymer blends in the vicinity of a glass and a liquid-liquid phase transition. The dramatic increase of local friction near Tg is accompanied by a slowing down of mass diffusion, whereas the Soret coefficient, which is a measure for the susceptibility to external temperature fields, remains unaffected by the glass transition. In sharp contrast is its divergence near a critical point which is caused by the critical slowing down of collective diffusion and an almost constant thermal diffusion coefficient. We show how this diverging susceptibility can be utilized for patterning of critical polymer blends both in the one and in the two phase regime.
[1] A. Voit, A. Krekhov, W. Enge, L. Kramer, W. Köhler. Phys. Rev. Lett. 92 (2005) 214501
[2] J. Rauch, W. Köhler. J. Chem. Phys. 119 (2003) 119777