Mechanically robust silicone networks enabled by tailored borneol-modified zwitterionic silane crosslinkers for sustainable marine antifouling

Silicone-based fouling release coatings (FRCs) are recognized as an environmentally benign antifouling technology, yet their broader application has been constrained by inherent limitations such as inadequate mechanical strength, weak substrate adhesion, and poor static antifouling performance. To overcome these challenges, this study successfully developed a novel borneol-modified zwitterionic silane crosslinker (IBOA-PSi) through “molecular integration design” and covalently integrated it into a commercial silicone polymer, yielding a series of modified coatings. Upon seawater exposure, IBOA-PSi undergoes controlled hydrolysis, releasing eco-friendly borneol and generating an in situ zwitterionic surface layer. This dual action significantly reduces protein adsorption (to as low as 0.9%), suppresses bacterial biofilm formation, and minimizes diatom adhesion (25% adhesion rate), while also promoting efficient fouling release under water flow (87% diatom removal at 1 Pa shear stress). After a 300-day marine field test, the developed coating shows only 10 barnacles, compared with 100 barnacles on the commercial silicone surface. Concurrently, acting as a flexible crosslinking unit, IBOA-PSi modulates the network topology of the siloxane matrix by reducing crosslink density and increasing cohesive energy density. These structural changes lead to remarkable enhancements in mechanical properties, including adhesion strength (up to 3.54 MPa), flexibility (bending diameter of 1 mm), and impact resistance (drop height of 10 cm). By combining robust mechanical performance with sustained antifouling functionality, this multifunctional silicone-based FRC demonstrates strong potential for durable and sustainable marine antifouling applications.