Structure and dynamics of solid-melt interfaces. A molecular dynamics study

Abstract

We performed a series of Molecular-Dynamics (MD) simulations in order to study the structure and microscopic dynamics of homopolymer melts confined between flat solid surfaces. Although computationally more demanding, MD simulations have two important advantages over Monte Carlo methods: They can reveal details of the polymer structure on the monomer scale (not accessible to lattice Monte Carlo approaches). They provide reliable information on the polymer molecular dynamics (not feasible with Monte Carlo unless the dynamical rules are chosen carefully for this specific purpose). In our simulations we modelled the polymer chain as a collection of beads (point masses) connected via FENE springs. Excluded volume was taken into account by assigning purely repulsive (truncated, shifted) Lennard-Jones (LJ) potentials to all beads. The parameters of the FENE and LJ potential are identical with those of Reference 5 and were carefully chosen to avoid any chain crossings. The results of the simulation are described in this paper.