One size fits all: equilibrating chemically different polymer liquids through universal long-wavelength description

TL;DR

This paper introduces a universal long-wavelength modeling approach for homopolymer melts, enabling the generation of chemically diverse polymer configurations from a single library, thus bridging coarse-grained and microscopic descriptions.

Contribution

It proposes a new class-based, universal blob description for polymers that allows hierarchical backmapping and efficient equilibration of large, chemically diverse polymer systems.

Findings

Library samples accurately reproduce melt structures

Hierarchical backmapping creates detailed configurations

Method enables microscopic simulation of large systems

Abstract

Mesoscale behavior of polymers is frequently described by universal laws. This physical property motivates us to propose a new modeling concept, grouping polymers into classes with a common long-wavelength representation. In the same class samples of different materials can be generated from this representation, encoded in a single library system. We focus on homopolymer melts, grouped according to the invariant degree of polymerization. They are described with a bead-spring model, varying chain stiffness and density to mimic chemical diversity. In a renormalization group-like fashion library samples provide a universal blob-based description, hierarchically backmapped to create configurations of other class-members. Thus large systems with experimentally-relevant invariant degree of polymerizations (so far accessible only on very coarse-grained level) can be microscopically described. Equilibration is verified comparing conformations and melt structure with smaller scale conventional simulations.