Individual Entanglements in a Simulated Polymer Melt

TL;DR

This study uses simulations to analyze monomer contact patterns in polymer melts, revealing persistent entanglements and their distinct dynamic behavior compared to non-entangled chains.

Contribution

It introduces a contact-based approach to identify and characterize entanglements in polymer melts, highlighting persistent contacts and their scaling properties.

Findings

Approximately 50% of contacts between entangled chains are persistent.

Entangled chains show different space-time contact correlation behavior than non-entangled chains.

Scaling properties of contact correlation functions are observed and explained.

Abstract

We examine entanglements using monomer contacts between pairs of chains in a Brownian-dynamics simulation of a polymer melt. A map of contact positions with respect to the contacting monomer numbers (i,j) shows clustering in small regions of (i,j) which persists in time, as expected for entanglements. Using the ``space''-time correlation function of the aforementioned contacts, we show that a pair of entangled chains exhibits a qualitatively different behavior than a pair of distant chains when brought together. Quantitatively, about 50% of the contacts between entangled chains are persistent contacts not present in independently moving chains. In addition, we account for several observed scaling properties of the contact correlation function.