Hierarchical Tough Hydrogel with Enhanced Rigidity and Extensibility for Strain Sensing, Posture Guide, and Injury‐Prevention

Abstract Hydrogels, as valuable biomaterials, have limited applications owing to their mechanical fragility. This study presents a structural modification approach to strengthen hydrogels mechanically. First, the precursor hydrogel undergoes deformation through stretching and twisting, resulting in a helical polymer structure and a deformation gradient. This deformed structure is then stabilized by densification and additional crosslinking. The twisted hydrogel shows improved extensibility and toughness owing to enhanced stress transfer in its unique structure. Additionally, multiple hydrogel strands are assembled hierarchically into ropes and cables, exhibiting advantageous mechanical properties such as high energy dissipation and durability. These reinforced mechanical features lead to considerable performance improvements in applications such as strain sensing and impact absorption. Furthermore, practical utility is demonstrated in areas including posture correction and injury prevention. The hydrogel reinforced by this method has the potential to be used in various fields where both mechanical properties and biocompatibility are crucial.