Biomimetic All-Weather Strong, Tough, and Fatigue-Resistant Composite Organohydrogels for Electronic Artificial Ligaments.

Gel materials have tremendous potential for application in future electronics and robotics due to their intriguing merits, like flexibility and biocompatibility. Nonetheless, conventional hydrogels' limited mechanical property and functionality have remarkably impeded their practical applications. Drawing inspirations from hierarchical anisotropic composite structure of natural hard biomaterials, this study proposes a freezing-casting assistant salting-out and solvent displacement with polyol strategy for the fabrication of composite organohydrogels with all-weather strong, tough, and fatigue-resistant mechanical features and functionalities (environmental stability and conductivity). By combining the hierarchical anisotropic fibrous microstructure with high crystallinity and abundant polymer-solvent interactions, the resulting organohydrogel displays exceptional stiffness (8.74 MPa), strength (21.20 MPa), stretchability (1556%), toughness (184.26 MJ m-3), fracture energy (768.3 kJ m-2), and fatigue threshold (7.86 kJ m-2). More importantly, the mechanical performances and conductivity of the gel are well-maintained at both cold and hot conditions, thus guaranteeing the application feasibility of the gel in extreme conditions. These intriguing merits enable the gel to exhibit superior potential in cutting-edge load-bearing applications, like electronic artificial ligaments. Therefore, this study presents a model approach that extends the fundamental design principles of natural biomaterials to engineer composite gels with synergistic mechanical and functional enhancements.