Constructing High Performance Hydrogels with Strong Underwater Adhesion through a “Mussel Feet-Rock” Inspired Strategy

In this study, high performance hydrogels with strong underwater adhesion were constructed through a "mussel feet-rock" inspired strategy, in which a random copolymer containing side-chain positive charges and catechol groups (PMD) simulated the adhesive proteins of mussel, and poly(acrylic acid) (PAA) mimicked the rocky surface. PMD and PAA chains could noncovalently cross-link together through hydrogen bonding, charge interaction, and chain entanglement. Catechol groups further provide the hydrogel strong adhesion ability. Taking advantage of this strategy, the obtained PAA/PMD hydrogels featured the best stretchability among reported hydrogels and intensive repeatable adhesion behavior, and further exhibited unusual wet-enhanced tensile and shear strength together with durable underwater adhesion. These findings are valuable for the development of mussel-inspired adhesives and high performance hydrogels.