Coarse grain forces in star polymer melts

L. Liu, Wouter K. den Otter, Willem J. Briels

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

An analysis is presented of forces acting on the centers of mass of three-armed star polymers in the molten state. The arms consist of 35 Kremer–Grest beads, which is slightly larger than needed for one entanglement mass. For a given configuration of the centers of mass, instantaneous forces fluctuate wildly around averages which are two orders of magnitude smaller than their root mean square deviations. Average forces are well described by an implicit many-body potential, while pair models fail completely. The fluctuating forces are modelled by means of dynamical variables quantifying the degree of mixing of the various polymer pairs. All functions and parameters in a coarse grain model based on these concepts are obtained from the underlying small scale simulation. The coarse model reproduces both the diffusion coefficient and the shear relaxation modulus. Ways to improve the model suggest themselves on the basis of our findings.
Original languageUndefined
Pages (from-to)7874-7886
Number of pages13
JournalSoft matter
Volume10
Issue number39
DOIs
Publication statusPublished - 2014

Keywords

  • METIS-306872
  • IR-94991

Cite this

Liu, L. ; den Otter, Wouter K. ; Briels, Willem J. / Coarse grain forces in star polymer melts. In: Soft matter. 2014 ; Vol. 10, No. 39. pp. 7874-7886.
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Coarse grain forces in star polymer melts. / Liu, L.; den Otter, Wouter K.; Briels, Willem J.

In: Soft matter, Vol. 10, No. 39, 2014, p. 7874-7886.

Research output: Contribution to journalArticleAcademicpeer-review

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AU - den Otter, Wouter K.

AU - Briels, Willem J.

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AB - An analysis is presented of forces acting on the centers of mass of three-armed star polymers in the molten state. The arms consist of 35 Kremer–Grest beads, which is slightly larger than needed for one entanglement mass. For a given configuration of the centers of mass, instantaneous forces fluctuate wildly around averages which are two orders of magnitude smaller than their root mean square deviations. Average forces are well described by an implicit many-body potential, while pair models fail completely. The fluctuating forces are modelled by means of dynamical variables quantifying the degree of mixing of the various polymer pairs. All functions and parameters in a coarse grain model based on these concepts are obtained from the underlying small scale simulation. The coarse model reproduces both the diffusion coefficient and the shear relaxation modulus. Ways to improve the model suggest themselves on the basis of our findings.

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KW - IR-94991

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