Strain‐Stiffening, Robust yet Compliant Ionic Elastomer from Highly Entangled Polymer Networks and Metal–Oxygen Interactions

Abstract Ion‐conductive elastomers have emerged as ideal candidates for ionic skin and wearable devices due to their intrinsic stretchability and excellent electrical properties. Despite continuous efforts in this field, strain‐stiffening, robust yet compliant ionic elastomers are still unattainable due to the limited intermolecular interactions, restricting their reliability and durability in practical applications. Inspired by the interwoven collagen fiber network and synergistic non‐covalent interaction in the dermis, an immense strain‐stiffening, ultra‐stretchable, highly tough, and elastic ionic elastomer are reported by introducing the metal–oxygen interactions into the highly entangled network. The ionic elastomers also show intriguing self‐healing ability, high adhesion, and environmental tolerance, contributed by the dynamic synergistic noncovalent interactions. The prepared ionic skin displays sensitive and stable responses to temperature and strain. This work demonstrates a new design strategy for fabricating high‐performance ionic elastomers with excellent mechanical and electrical properties, showing great prospects in wearable and flexible devices.