Hydrogel Adhesives Against Interfacial Mismatch Induced by Extreme Dryness via Water‐State Reconstruction

Interfacial mismatch induced by dehydration compromises the long‐term operational stability of hydrogel‐integrated assemblies. Here, we introduce a water‐state reconstruction strategy that establishes a quasi‐steady medium around polymer chains, in which trehalose is anchored to the network via strong hydrogen bonding and, coupled with its exceptional hydration capacity, stabilizes surrounding free water to suppress solvent loss under harsh conditions. This molecular‐level hydration control suppresses dehydration‐induced shrinkage and stiffening while enhancing interfacial toughness. The resulting hydrogel achieves an interfacial toughness of 1900 J m − 2 , among the highest reported for physically adhesive hydrogels, and enables a flexible supercapacitor to operate at 60°C for 24 h with minimal performance decay. This work establishes water‐state reconstruction as a general design principle for dehydration‐resistant integration in soft‐material systems.