Computational Indentation in Highly Cross-linked Polymer Networks

TL;DR

This paper uses computational indentation to explore the relationship between structure and mechanics in highly cross-linked polymer networks, revealing their hardening behavior and the role of network rearrangements.

Contribution

It introduces a computational model to study indentation in HCP networks, linking microstructural changes to mechanical response, which is less explored compared to other polymer systems.

Findings

HCP networks harden upon indentation.

Local bond breaking correlates with network rearrangement.

Comparison with elastic-plastic deformation model confirms findings.

Abstract

Indentation is a common experimental technique to study the mechanics of polymeric materials. The main advantage of using indentation is because this provides a direct correlation between the microstructure and the small-scale mechanical response, which is otherwise difficult within the standard tensile testing. Here, majority of studies have investigated hydrogels, microgels and/or elastomers. However, a lesser investigated system is the indentation in highly cross-linked polymer (HCP) networks, where the complex network structure plays a key role in dictating their physical properties. In this work, we investigate the structure-property relationship in HCP networks using the computational indentation of a generic model. We establish a correlation between the local bond breaking, the network rearrangement, and the small-scale mechanics. The results are compared with the elastic-plastic deformation model. HCPs harden upon indentation.