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Equilibration of long chain polymer melts in computer simulations.

Journal Article · · Proposed for publication in Journal of Chemical Physics.
OSTI ID:993915

Several methods for preparing well equilibrated melts of long chains polymers are studied. We show that the standard method in which one starts with an ensemble of chains with the correct end-to-end distance arranged randomly in the simulation cell and introduces the excluded volume rapidly, leads to deformation on short length scales. This deformation is strongest for long chains and relaxes only after the chains have moved their own size. Two methods are shown to overcome this local deformation of the chains. One method is to first pre-pack the Gaussian chains, which reduces the density fluctuations in the system, followed by a gradual introduction of the excluded volume. The second method is a double-bridging algorithm in which new bonds are formed across a pair of chains, creating two new chains each substantially different from the original. We demonstrate the effectiveness of these methods for a linear bead spring polymer model with both zero and nonzero bending stiffness, however the methods are applicable to more complex architectures such as branched and star polymer.

Research Organization:
Sandia National Laboratories
Sponsoring Organization:
USDOE
DOE Contract Number:
AC04-94AL85000
OSTI ID:
993915
Report Number(s):
SAND2003-2449J
Journal Information:
Proposed for publication in Journal of Chemical Physics., Journal Name: Proposed for publication in Journal of Chemical Physics. Journal Issue: 24 Vol. 119; ISSN JCPSA6; ISSN 0021-9606
Country of Publication:
United States
Language:
English