Intrinsically reversible superglues via shape adaptation inspired by snail epiphragm

Significance Achieving both superstrong adhesion and reversibility is challenging, particularly for hydrogels. Here, we report a hydrogel-based, reversible, superglue-like adhesive by combining the benefits of both liquid and dry adhesives in a single material while overcoming their respective limitations. When hydrated, the softened gel conformally adapts to the target surface by low-energy deformation, which is then locked upon drying as the elastic modulus is raised from hundreds of kilopascals to a few gigapascals, analogous to the action of the epiphragm of snails. We show that reversible superstrong adhesion could be achieved from a nonstructured material when the criterion of shape adaption is met, with minimal residual strain energy stored in the system.