Molecular simulation of structural and dynamic properties of polymer nanoparticles composed of linear and cyclic polyethylene

Abstract

Polymer nanoparticles were investigated using Monte Carlo simulation of coarse-grained linear and cyclic polyethylene (PE). The method employs the Flory’s rotational isomeric state (RIS) model and Lennard-Jones potential; respectively, for intra- and inter-molecular interaction. The density of nanoparticle with cyclic chains is slightly higher than that of linear polymers, and the interfacial region is slightly narrower. Structural and orientational properties of linear and ring chains are quite similar. Increased mobility toward the free surface on the scale of beads, bonds and chain is due to the decrease in density. Cyclic polymers move slower than the linear chains. The region of an increased mobility is deeper than the bond length and is attributed to the low density in the surface region rather than to the segregation of chain ends. Rotational and translational motion are faster for linear chains before the molecules encounter the confinement effect of nanoparticles, then there is the cross-over point and chains move slower.