In Situ Formation of Breathable Elastic Nanophase Enabling Wet Adhesion Strength over Triple of Dry Adhesion

Wet adhesion is essential in various fields. However, interfacial liquid, hardly eliminated, dampens contact between adhesives and adherends. Consequently, achieving robust adhesion in liquid media faces great challenges, typically less than 1 MPa. In this work, a series of linear polyacrylate with different glass-transition temperatures, insoluble in liquid media, are respectively dissolved in monomers immiscible with liquid to form glues, with both underwater and underoil adhesion strength over triple of dry adhesion. Strengthened wet adhesion is attributed to interfacial anchorable nanoparticles originating from a "breathable elastic nanophase" formed in situ during the phase separation process induced by liquid media, which enables continuous interdiffusion of monomer and liquid media for phase separation as well as dispersed morphology with its elastic. By simply adjusting the phase separation process and nanophase structure, underwater adhesion strength is up to 15.60 MPa, and even for oil with high viscosity and low surface tension, the underoil adhesion strength is up to 14.38 MPa, both more than three times dry adhesion strength, topping the highest wet adhesion strength reported. Moreover, robust adhesion to plastics and metal in harsh environments including acid, alkali, and 0 °C water has been achieved. The research provides a new approach for high adhesion strength in a liquid environment.