Super-stretchable Elastomer from Cross-linked Ring Polymers

TL;DR

This study demonstrates through molecular dynamics simulations that cross-linked ring polymers exhibit significantly higher stretchability than linear polymers due to their unique entanglement structure and conformation.

Contribution

The paper introduces the concept that cross-linked ring polymers are more stretchable than linear polymers, challenging traditional understanding based on entanglements.

Findings

Cross-linked ring polymers are more stretchable than linear polymers.

Entanglements in ring polymers do not act as effective cross-links.

Stretchability depends on maximum extension of strands between cross-links.

Abstract

The stretchability of polymeric materials is critical to many applications such as stretchable electronics and soft robotics, yet the stretchability of conventional cross-linked linear polymers is limited by the entanglements between polymer chains. We show using molecular dynamics simulations that cross-linked ring polymers are significantly more stretchable than cross-linked linear polymers. Compared to linear polymers, the entanglements between ring polymers do not act as effective cross-links. As a result, the stretchability of cross-linked ring polymers is determined by the maximum extension of polymer strands between cross-links, rather than between entanglements as in cross-linked linear polymers. The more compact conformation of ring polymers before deformation also contributes to the increase in stretchability.