Ultrastretchable, fatigue-resistant eutectogel with hierarchical bonding for advanced wearable monitoring

Wearable healthcare and IoT applications demand conductors that are tough, stretchable, and exhibit skin-like elasticity, advanced sensing capabilities, and durability under dynamic conditions. However, conventional ionic conductors, such as hydrogels and eutectogels, suffer from low ionic conductivity, poor fatigue resistance, and limited adaptability to deformation, constrained by trade-offs between mechanical robustness and electrical performance. Here, we present an ultrastretchable, fatigue-resistant organic mixed ionic-electronic conductor (OMIEC) eutectogel that addresses these challenges by enhancing inherently competing properties through a novel hierarchical bonding network. This structure integrates dynamic hydrogen bonds within a polymerizable deep eutectic solvent (PDES) matrix and hydrophobic interactions derived from rigid, mixed-conductive domains, forming a robust conducting gel network. This synergistic design significantly enhances toughness, fracture resistance, conductivity, and electromechanical sensitivity, while maintaining ultralow electromechanical hysteresis (≤ 1%) under strains up to 1,500%. The OMIEC eutectogel demonstrates a 66-fold increase in conductivity, a 6.2-fold improvement in fracture energy, and a 4.5-fold enhancement in toughness, complemented by self-healing properties that extend fatigue life beyond 100,000 cycles. By integrating these capabilities, the material eliminates traditional trade-offs, enabling precise and stable monitoring of physiological motion, temperature, and complex human gestures in dynamic environments. This multifunctional eutectogel establishes a transformative platform for next-generation wearable bioelectronics, providing unparalleled stretchability, durability, and multi-sensing performance for applications in health monitoring, soft robotics, and IoT systems.