Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 27: POSTER Polymer Physics and Materials
CPP 27.13: Poster
Donnerstag, 30. März 2006, 17:00–19:00, P2
Faster dynamics in thin polymer films? — •Anatoli Serghei1, Lutz Hartmann1, Yulia Mikhailova2, Klaus-Jochen Eichhorn2, Brigitte Voit2, and Friedrich Kremer1 — 1Leipzig University, Institute for Experimental Physics I, Leipzig, Germany — 2Leibniz Institute of Polymer Research, Dresden, Germany
The molecular dynamics in thin films of polymers with different macromolecular architectures (linear and hyperbranched structures) are investigated by Broadband Dielectric Spectroscopy. Pronounced confinement-effects are detected: the average relaxation rate of the dynamic glass transition increases with decreasing film thickness, indicating a faster dynamics in thin films. The molecular mechanism of these effects is revealed by the quantitative determination of the relaxation time distribution in dependence on the confinement size. It turns out that: a) the increase in the average relaxation rate is caused by a gradual suppression (freezing-out) of the slower relaxation modes in confinement; b) at a molecular level no polymer segments are found to relax faster in thin films than in the bulk.
L. Hartmann et al., Eur. Phys. J. E 8, 145 (2002). A. Serghei et al., Eur. Phys. J. E 17, 199 (2005).