Hydroelastomers: soft, tough, highly swelling composites

TL;DR

Hydroelastomers are innovative composites combining swelling hydrogel particles within tough elastomer matrices, offering high toughness, minimal softening upon swelling, and versatile shape-morphing capabilities for applications in soft robotics and actuators.

Contribution

This work introduces a new class of hydroelastomers that integrate swelling hydrogels into elastomer matrices, enabling tough, highly swellable composites with customizable properties.

Findings

Exhibit high toughness comparable to best hydrogels

Show minimal softening during swelling

Easily fabricated with commercial materials

Abstract

Inspired by the cellular design of plant tissue, we present a new approach to make versatile, tough, highly water-swelling composites. We embed highly swelling hydrogel particles inside tough, water-permeable, elastomeric matrices. The resulting composites, which we call \emph{hydroelastomers}, show little softening as they swell, and have excellent fracture properties that match those of the best-performing, tough hydrogels. Our composites are straightforward to fabricate, based on commercial materials, and can easily be molded or extruded to form shapes with complex swelling geometries. Furthermore, there is a large design space available for making hydroelastomers, since one can use any hydrogel as the dispersed phase in the composite, including hydrogels with stimuli-responsiveness. These features should make hydroelastomers excellent candidates for use in soft robotics and swelling-based actuation, or as shape-morphing materials, while also being useful as hydrogel replacements in a wide range of other fields.