The effect of bond length on the structure of dense bead-spring polymer melts

We explored the effect of the ratio of bond length to excluded volume bead diameter, l(0)/d(0), of simple bead-spring homopolymer chains on the resulting liquid structure of dense, monodisperse polymer melts. We conducted NVT molecular dynamics simulations of both bulk and planar confined polymer liquids. We find that both pressure and surface tension increase with l(0)/d(0). We attribute this sensitivity to the reduction in short range liquid ordering, classically observed for simple fluids, when l(0)/d(0)<1, and its persistence and even enhancement when l(0)/d(0)>1. We explain this by examining specific correlations between bond orientations and monomer density. This leads to a better understanding of how intramolecular constraints influence intermolecular structure in molecular liquids. (C) 2001 American Institute of Physics.