Multinetwork Hydrogel/Polydimethylsiloxane Composite Elastomer with Ultrahigh Toughness and Broad-Range Strain Sensing

Abstract To overcome the inherent electrical insulation and limited stretchability of polydimethylsiloxane (PDMS), a transparent, highly tough, ionically conductive hydrogel-based PDMS elastomer was developed via a synergistic multinetwork and water–oil equilibrium strategy. The elastomer integrates a covalent poly(acrylic acid) network, dual dynamic boronate ester networks, and a hydrogen-bonding network of polyethylene glycol (PVA) and glycerol. The resulting PDMS/PVA/Tannic acid/Borax/Acrylic acid (PPTBA) composite elastomer exhibits a tensile strength of 1780 kPa, an elongation at break of 980%, and a toughness approximately five times that of pure PDMS. As a flexible sensor, it delivers an ionic conductivity of 0.7 S/m, a gauge factor ranging from 0.716 to 2.8 over a strain range of 0–570%, fast response and recovery times (659 and 668 ms), and outstanding cyclic stability over 700 tensile loading-unloading cycles. The sensor enables accurate real-time monitoring of diverse human motions, from subtle muscle contractions to large-amplitude joint flexion, and can be seamlessly integrated into human-machine interaction systems for synchronous robotic gripper control. Furthermore, it reliably identifies vehicle weight categories and estimates speed through distinct resistance signal patterns, as validated by finite element analysis. This work presents a generalizable strategy for reconciling the long-standing trade-off between mechanical robustness and high sensing performance, advancing next-generation wearable health monitors, intelligent human-machine interfaces, and smart transportation systems.