Kramers potential study of the Rouse-like dynamics of short alkane chains.
In this work we present a Kramers potential study of the orientational dynamics and shear viscosity of short chain alkanes. In this approach the determination of the orientational relaxation time is reduced to the calculation of static moments of single chain conformations. We study a chemically realistic alkane model that asymptotically produces Gaussian chain conformations by means of a Monte Carlo simulation. Our results are applicable to single chain descriptions of polymer melt dynamics and to the intrinsic viscosity of molecules in a Theta solvent. When we map the unknown time unit of our relaxation time result for one particular chain length and temperature to the value obtained for the same parameters from a molecular dynamics simulation of a melt of these chains, we are able to reproduce the experimental data on the chain length dependence of the melt viscosity of alkane chains at this temperature.
Paul
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W
Institut für Physik, Johannes-Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany.
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