# Bioinspired super-tough polyurethane elastomers with block modules using sacrificial bonds

## TL;DR

A bioinspired polyurethane material was developed that is highly stretchable, tough, and self-healing, suitable for use in soft robotics and electronic skin.

## Contribution

The paper introduces a novel biomimetic strategy using synergistic dynamic bonds to create super-tough, self-healing polyurethane elastomers.

## Key findings

- The elastomer achieved high tensile stress (∼30 MPa) and stretchability (∼4100%).
- Exceptional toughness (∼470 MJ m−3) and self-healing ability were demonstrated.
- The material combines multiple hydrogen bonds and metal coordination bonds for enhanced performance.

## Abstract

Stretchable and self-healable elastomers with excellent mechanical properties can find attractive applications in electronic skin, soft robotics, and electrical devices. To date, it remains a huge challenge to synthesize self-healing elastomers that integrate extreme stretchability, relatively high toughness, and high self-recoverability. Herein, inspired by biological tissues and mussel byssus, we circumvent this dilemma by introducing multiple hydrogen bonds (UPy) and metal coordination bonds (DAP-Fe(iii)) into a linear polyurethane network. The self-complementary quadruple hydrogen-bond interactions between UPy dimers were incorporated as physical cross-linkages, with greatly enhanced mechanical strength and high stretchability. In addition, strong Fe-coordination bonds can readily break and re-form, a feature that facilitates energy dissipation during stretching, leading to significantly improved robustness while maintaining stretchability. The polyurethane elastomer exhibited all the desired properties, including high tensile stress (∼30 MPa), high stretchability (∼4100%), exceptional toughness (∼470 MJ m−3), excellent self-recoverability, and self-healing ability. This biomimetic strategy of using synergistic dynamic bonds as block modules is an alternative approach for obtaining advanced polymers.

A bioinspired polyurethane elastomer with multiple hydrogen bonds and metal coordination bonds was prepared, exhibiting desirable properties such as high tensile stress, stretchability, and exceptional toughness.