Structural Engineering of Reversible Hydrogel Nanocomposites for Dehydration‐Free and Highly Durable Wearable Sensing Arrays

Hydrogels consist of crosslinked polymer chains that can hold substantial water within their 3D architectures. Nevertheless, most of this water exists in an unbound state, rendering progressive dehydration an inherent limitation that undermines fracture toughness and long‐term fatigue durability. Although PVA/glycerol binary systems have been extensively investigated to address dehydration, they consistently entail a critical trade‐off either exhibiting low mechanical stiffness or lacking quantified fatigue thresholds, fundamentally limiting their long‐term wearable reliability. We demonstrate that suppressing dehydration through precise humectant engineering directly enhances mechanical durability. In this study, we designed interlinked structures using enhanced intermolecular association and dense networks enabled by dynamic plasticization‐controlled chain mobility. We also observed that, after 7 days of dehydration, the hydrogel with a hybrid conductive network via optimal polymerization and the incorporation of functional additives led to high ultimate tensile strength (~2131 kPa), modulus (~685 kPa), fracture toughness (~3365 J/m ² ), and fatigue threshold (~183 J/m ² ), and an excellent gauge factor of 1.66 in the strain range of 100%–200%. These results establish a new performance benchmark for fatigue‐resistant hydrogel sensors in wearable and flexible electronics. Durable, conductive hydrogels will improve clinical monitoring devices and advanced soft robots, thereby modernizing healthcare and automation.