Dynamics of Soliton-Like Excitations in a Chain of a Polymer Crystal: Influence of Neighbouring Chains Mobility

Abstract

We investigate influence of mobility of neighbouring chains on dynamics of soliton-like excitations in a chain of the simplest polymer crystal (polyethylene in the “united atoms ” approximation) using molecular dynamics simulation. We present results for point-like structural defects: static and moving at low, medium and high velocities; and examine howthe structure of a crystal will affect them. 1Introduction The present work is concerned with the behaviour of a system presumed to be close to an integrable one, namely Sine-Gordon system. Sine-Gordon equation is well known to be the simplest continual one-dimensional model of a dislocation in a crystal (the well known Frenkel–Kontorova model). It can be equally used to describe nonlinear dynamics of a directed macromolecular chain subjected to a periodic potential [1, 2]. Because it is a periodic potential which is generated by immobile neighbouring chains in a polymer crystal, it was supposed that one can identify topological solitons of Sine-Gordon type with point defects in a polymer chain (vacancies and inclusions) which are caused by loca