Recyclable Underwater Adhesive with Rapid Curing, High Strength, and Long-Term Durability

Abstract

Developing underwater adhesives that combine rapid curing, high adhesion strength, recyclability, and long-term durability remains a significant challenge. Here, we report a recyclable underwater adhesive (AMN) synthesized via one-pot UV-initiated copolymerization of acrylic acid (AA), acrylamide (AM), and N-benzylacrylamide (NBAM) in dimethyl sulfoxide (DMSO). The adhesive exploits synergistic hydrogen bonding, hydrophobic interactions, and π–π stacking to achieve strong and stable adhesion on various substrates. Under optimal conditions (monomer mass fraction 22%, NBAM dosage 65%, photoinitiator 5%, UV irradiation 3 h), the adhesive exhibits a shear adhesion strength of 235 kPa on polycarbonate (PC) substrates, reaching 200 kPa within 10 min. Notably, the adhesive can be reversibly disassembled in ethanol (100% dissolution within 7 h) while remaining stable in tap water for over 7 days. After five reuse cycles, 76% of the original adhesion strength (178.5 kPa) is retained. The adhesive also maintains stable performance on PC for 100 days. This work provides a green, solvent-responsive, and durable adhesive platform with promising applications in marine engineering, biomedical devices, and flexible electronics.