Design of Double‐Network Click‐Gels for Self‐Contained Underwater Adhesion and Energy‐Wise Applications in Floating Photovoltaics

Abstract Facile fabrication of rapid, firm, and reversible underwater adhesion used on different adherets is challenging but is of primary importance for many industrial and biomedical applications. Herein, tough, stretchy, moldable, and semitransparent gels are developed for self‐contained underwater adhesives. The selected structural components, well‐defined double‐network (DN) structures, and one‐pot synthesis realize synergistic adhesion and cohesion engineering, which deliver instant, solid, reversible, and long‐term adhesives with a high underwater adhesion strength of over 0.84 MPa. The underwater adhesion strength is among the best‐performing tape‐type underwater adhesives. In order to develop new energy‐related applications for underwater adhesion, the first example of combining underwater adhesion with solar power applications is demonstrated. Taking the benefits of the direct‐contact design at the air/water interface, the click‐gel‐mounted floating photovoltaic (FPV) system significantly increases the power conversion efficiency by 20% due to the enhanced active cooling effects, surpassing several conventional photovoltaic technologies on both land and water. The click‐gel also rapidly responds to several oscillatory motions on the FPV platform. This study shines a light on the facile fabrication of DN click‐gels for underwater adhesives and provides their future perspectives in energy‐wise, low‐maintenance, and stimuli‐responsive applications.