Ultrarobust and water-insensitive healable elastomers from hydrophobic multiple phase-locking microstructures

Abstract

Although there has been a series of research about self-healing elastomer materials, the trade-off between their mechanical robustness, self-healing efficiency, and water-insensitive properties has not been well settled in practical applications, especially for aqueous environments. Herein, a hydrophobic multiple phase-locking strategy is presented to integrate the above-mentioned paradoxical performances into polyurethane elastomer by introducing long-chain fatty acid and disulfide bonds to decorate the microphase-separated structure. Disulfide bonds contribute to the dynamic network to ensure self-healing. Long-chain fatty acids induced the formation of hydrophobic microstructures that contributed both mechanical toughness and significant water repellency. As a result, the elastomer has a tensile strength of 41.0 MPa and a strain of 1485.2 %. Moreover, the healing efficiency in the air is >99 % and it maintains a tensile strength of 25 MPa even after 24 h of healing in different aqueous environments (acidic, alkaline and saline solutions). Furthermore, a human-machine interface-based sensor is created by incorporating ionic liquids to elucidate the potential applications, and the other potential of the elastomer for commercial applications is also validated. This research provides a new method for water-insensitive healing materials with robust mechanical performances.