Stretchable hydrogels with low hysteresis and anti-fatigue fracture based on polyprotein cross-linkers

Nat Commun. 2020 Aug 12;11(1):4032. doi: 10.1038/s41467-020-17877-z.

Abstract

Hydrogel-based devices are widely used as flexible electronics, biosensors, soft robots, and intelligent human-machine interfaces. In these applications, high stretchability, low hysteresis, and anti-fatigue fracture are essential but can be rarely met in the same hydrogels simultaneously. Here, we demonstrate a hydrogel design using tandem-repeat proteins as the cross-linkers and random coiled polymers as the percolating network. Such a design allows the polyprotein cross-linkers only to experience considerable forces at the fracture zone and unfold to prevent crack propagation. Thus, we are able to decouple the hysteresis-toughness correlation and create hydrogels of high stretchability (~1100%), low hysteresis (< 5%), and high fracture toughness (~900 J m-2). Moreover, the hydrogels show a high fatigue threshold of ~126 J m-2 and can undergo 5000 load-unload cycles up to 500% strain without noticeable mechanical changes. Our study provides a general route to decouple network elasticity and local mechanical response in synthetic hydrogels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylic Resins / chemistry
  • Cross-Linking Reagents / chemistry*
  • Fluorescence
  • Hydrogels / chemistry*
  • Mechanical Phenomena
  • Polyproteins / chemistry*
  • Stress, Mechanical*

Substances

  • Acrylic Resins
  • Cross-Linking Reagents
  • Hydrogels
  • Polyproteins
  • polyacrylamide