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arXiv · 0808.0891

Dynamics of a stretched nonlinear polymer chain

M. Febbo·A. Milchev·V. Rostiashvili·T. A. Vilgis·D. Dimitrov
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Abstract

We study the relaxation dynamics of a coarse-grained polymer chain at different degrees of stretching by both analytical means and numerical simulations. The macromolecule is modelled as a string of beads, connected by anharmonic springs, subject to a tensile force applied at the end monomer of the chain while the other end is fixed at the origin of coordinates. The impact of bond non-linearity on the relaxation dynamics of the polymer at different degrees of stretching is treated analytically within the Gaussian self-consistent approach (GSC) and then compared to simulation results derived from two different methods: Monte-Carlo (MC) and Molecular Dynamics (MD). At low and medium degrees of chain elongation we find good agreement between GSC predictions and the Monte-Carlo simulations. However, for strongly stretched chains the MD method, which takes into account inertial effects, reveals two important aspects of the nonlinear interaction between monomers: (i) a coupling and energy transfer between the damped, oscillatory normal modes of the chain, and (ii) the appearance of non-vanishing contributions of a continuum of frequencies around the characteristic modes in the power spectrum of the normal mode correlation functions.

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M. Febbo, A. Milchev, V. Rostiashvili, T. A. Vilgis, D. Dimitrov. 2008-08-06. Dynamics of a stretched nonlinear polymer chain. https://doi.org/10.1063/1.2993136

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