Perspective on Networks and Gels: Soft but Dynamic and Tough

I recently wrote a perspective paper for the 50th annivesary of Macromolecules on the mechanical properties of networks and gels, that tries to highlight recent developments and to suggest promising future research topics. I hope it will be of interest to people working in the field.

accepted version

Published version

Abstract

Soft polymer networks have seen an explosion of recent developments motivated by new high tech applications in the biomedical field or in engineering. We present a candid and critical overview of the current understanding of the relation between the structure and molecular architecture of polymer networks and their mechanical properties, restricting ourselves to soft networks made of flexible polymers and displaying entropic elasticity. We specifically review and compare recent approaches to synthesize swollen hydrogels with enhanced toughness, resilient but tough unfilled elastomers and self-healing networks containing dynamic bonds. The purpose is less to draw a comprehensive catalogue of approaches than to identify and unify the underlying principles controlling toughening mechanisms and mechanical self-healing behaviour and to point out remaining challenges.