A Biomimicking Non‐Swelling Wet Tissue Adhesive With Instant, Tough, and Durable Adhesion for Wound Closure

ABSTRACT Durable tough underwater tissue adhesion presents a big challenge due to the inherent materials science trade‐off between robust interfacial bonding and cohesion strength. Inspired by the synergistic adhesion mechanisms of mussel foot proteins and barnacle cement proteins, we designed and synthesized a novel adhesive via UV‐initiated copolymerization of four acrylate monomers: a long‐chain alkyl catechol derivative (Cd), its phenolic analogue (Cs), hydroxyethyl acrylate (HEA) , and dimethylaminoethyl methacrylate (DMA) . Its adhesion is water‐triggered, fast (<1 min), tough (underwater tissue adhesion strength: ∼388 kPa; interfacial toughness: ∼530 J/m 2 ), due to the strong interfacial interactions at the adhesive/adherend interface, and the good energy dissipation capacity from the high cohesive mechanical properties (stress: 724 kPa, strain: 395%, and toughness : 864 kJ/m 3 ). Moreover, its adhesion strength to underwater tissue is durable for up to 14 d, attributable to its non‐swelling properties (water adsorption ratio is just ∼4%). It can effectively close tissue incisions and facilitate wound healing. This study elucidates the influence of catechol groups, cationic moiety, and hydrophobic segments on underwater adhesion, and therefore develops a non‐swellable wet tissue adhesive for better serving the clinical needs.