Pressure-sensitive in-situ underwater adhesives

This study reports the development of a pressure-sensitive in-situ (PSIS) underwater adhesive composed of superabsorbent polymer particles infused with functional silane and hydrogel precursors. The adhesive rapidly absorbs interfacial water, while externally applied mechanical pressure and heat promote particle–particle contact, bulk polymerization, and covalent bonding with wet substrates. Systematic experiments demonstrated that applied mechanical pressure significantly enhanced adhesive stretchability, stiffness, fracture toughness, and interfacial toughness, enabling strong underwater adhesion comparable to air-cured systems. The work establishes a design framework for robust in-situ underwater repair materials relevant to marine infrastructure, robotics, and electronics.