Density effects in entangled solutions of linear and ring polymers

TL;DR

This study uses Molecular Dynamics simulations to compare how linear and ring polymers behave in entangled solutions, revealing differences in conformations, relaxation, and local viscoelastic properties across densities.

Contribution

It provides a detailed comparison of linear and ring polymers' static and dynamic properties in entangled solutions, highlighting topology-dependent behaviors.

Findings

Linear chains obey Gaussian statistics at all densities.

Ring polymers become more compact as density increases.

Ring polymers relax faster than linear chains.

Abstract

In this paper, we employ Molecular Dynamics computer simulations to study and compare the statics and dynamics of linear and circular (ring) polymer chains in entangled solutions of different densities. While we confirm that linear chain conformations obey Gaussian statistics at all densities, rings tend to crumple becoming more and more compact as density increases. Conversely, contact frequencies between chain monomers are shown to depend on solution density for both chain topologies. Relaxation of chains at equilibrium is also shown to depend on topology, with ring polymers relaxing faster than their linear counterparts. Finally, we discuss the local viscoelastic properties of the solutions by showing that diffusion of dispersed colloid-like particles is markedly faster in the rings case.