A hydrophobic phase-locking strategy enabling ultrarobust and water-stable self-healing elastomers for underwater ionotronics

Water-resistant conductive elastomers can endow soft electronic devices with reliable sensing performance for motion monitoring and real-time communication in aquatic environments. Nevertheless, traditional conductive elastomers typically suffer from notable shortcomings in terms of inferior mechanical robustness, weak stability, and self-healing capabilities in wet conditions and even underwater, significantly restricting their practical utility. Drawing inspiration from the optimization of multiphase structure, an ultrarobust underwater healable elastomer is constructed by incorporating biomass-derived long-chain segments with a large number of amide/benzene groups into a hierarchical H-bonding supramolecular network. The locking of multiple dynamic bonds by uniformly distributed hard-phase domains with dense hydrophobic barriers leads to the resultant elastomer gaining remarkably enhanced mechanical properties (stretchability, 2217.2 %; toughness, 272.97 MJ m −3 ) and outstanding capability to autonomously self-heal even underwater with a high ultimate strength over 10 MPa (aqueous healing for 24 h). Notably, it boasts exceptional healing stability to all types of harsh aqueous environments, such as strong acid/alkali, high temperature, and salty water. The application of the developed elastomer is also demonstrated by creating a multifunctional wearable sensor that can accurately detect and transmit information for a variety of human motions in both atmospheric and aquatic environments. The viable strategy reported herein for designing advanced multifunctional healable materials can be applicable for all-environment flexible iontronic devices.