Soft coarse-grained models for multicomponent polymer melts: <br/><br/> free energy and single-chain dynamics

Monday, November 3, 2008 - 2:00pm - 2:45pm
EE/CS 3-180
Marcus Müller (Georg-August-Universität zu Göttingen)
In soft, coarse-grained models for dense polymer liquids, harsh
repulsive interactions (excluded volume) between segments are
replaced by soft repulsive interactions, which are sufficient to suppress
density fluctuations. These models allow to efficiently study polymer
melts with an experimentally relevant invariant degree of polymerization
by computer simulation. Two topics will be discussed:
(i) The calculation of free energies in self-assembling systems will be
illustrated by studying the interface free energy of two lamellar grains
of a symmetric diblock copolymer melt with perpendicular orientation
(ii) The softness of the segmental interactions in coarse-grained models
does not guarantee non-crossability of the molecules during the course of
their motion. The effect of these topological constraints, which lead to
reptation dynamics in dense melts of long flexible molecules, can be mimicked
by slip-links and application of slip-links to the single-chain dynamics in
the disordered and lamellar phase will be discussed.
MSC Code: