Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 26: Polymer Dynamics
CPP 26.2: Vortrag
Mittwoch, 16. März 2011, 10:45–11:00, ZEU 160
Short time dynamics of medium length molecules — •Humphrey Morhenn1, Sebastian Busch1, Dieter Richter2, and Tobias Unruh3 — 1Technische Universität München, Forschungs-Neutronenquelle Heinz Maier-Leibnitz and Physik Department E13, 85747 Garching, Germany — 2Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 3Lehrstuhl für Kristallographie und Strukturphysik, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
The description of transport mechanisms in molecular liquids is a challenging task. Especially the mechanism of molecular self-diffusion in liquids of organic medium-chain molecules is not fully understood yet. TOF-QENS experiments were performed on a polyethylene melt (n-C100H202), and a polydimethylsiloxane melt (PDMS, molecular weight approx. 17,250). Both chains are long enough to show gaussian chain statistics in their confirmations so that it was possible to check the validity of the Rouse model on this time and length scale. It could be shown that the simple Rouse model cannot describe the TOF-QENS data satisfactorily but respecting a reduced local chain flexibility by a mode dependent friction coefficient the Rouse model can surprisingly reproduce the experimental data of PE down to t = 1 ps.