Tough Yet Reversible Hydrogel Adhesives with Cooperative Energy Dissipation for Multifunctional Wearable Sensors

Abstract Achieving robust yet reversible adhesion between hydrogels and diverse substrates is of great importance and technically challenging. A family of phase‐segregated hydrogel adhesives with cooperative energy dissipation is reported. The resultant hydrogels display abundant nano‐aggregates comprising hydrophobic clusters and hydrogen‐bonded nanocrystals for efficient dissipation, and accumulated interfacial physical bonding like hydrogen bonding and hydrophobic interactions for intrinsic adhesion work, thus synergistically leading to super tough yet reversible adhesion. Additionally, the size of nano‐aggregates can be well‐tuned by varying time of solvent exchange followed by dry‐annealing and swelling, thus enabling switchable mechanical robustness and water content as well as unprecedented interfacial toughness exceeding 3300 J m −2 on the polyhydric surfaces. Multifunctional stretchable and pressure sensors with high sensitivity and ionic conductivity are also demonstrated.