A starch-bridging strategy for achieving multi-performance synergy of solid-state ionic elastomers toward multimodal...

Solid-state ionically conductive elastomers, combining stretchability and ionic conductivity, hold considerable promise for flexible sensing. Yet, synergistically enhancing mechanical and ionic properties while integrating self-healing and multimodal sensing through a simple synthesis remains challenging. Herein, using sodium carboxymethyl starch (CMS) as a macromolecular bridging agent, we prepared a liquid-free ionically conductive elastomer (PBCaC_x) via a one-pot method in a polymerizable deep eutectic solvent. The dynamic coordination interactions between -COO^- groups of CMS and Ca²⁺, together with multiple hydrogen bonds, reinforces the network, while CMS introduces Na⁺ and promotes Cl^- dissociation, assisted by -COO^- and abundant -OH groups to construct efficient ion transport channels. This dual-bridging regulation mechanism enhances mechanical properties (tensile strength of 4.85 MPa, elongation at break of 700% for PBCaC₆) and ionic conductivity (0.11 S m^-1 for PBCaC₈), endowing the material with excellent self-healing capability. The assembled sensor delivers a wide strain response, high sensitivity (GF = 1.031), a temperature coefficient of resistance of 9.5% K^-1, and a temperature resolution of 0.1 °C, enabling simultaneous real-time monitoring of human motion and body temperature for multimodal physiological sensing. This work provides a versatile strategy for designing high-performance flexible ionic conductors based on biomacromolecules, showing significant potential in wearable electronics.