Trace Polyurethane-Enhanced Scrubbing Resistance in UV-Curable Amphiphilic Antifouling Transparent Coatings

Marine biofouling significantly increases the hydrodynamic drag and energy consumption while impairing the transparency and signal transmission of underwater optical equipment. To achieve protection for transparent underwater equipment, this work utilizes 3-(trimethoxysilyl)propyl methacrylate (Silane A174) as a cross-linking site, which enables cross-linking between silicone resin and acrylic resin (where polydimethylsiloxane and polyethylene glycol contribute amphiphilic surfaces). Employing UV curing, a transparent antifouling coating was obtained with high curing efficiency (30 min). The incorporation of cross-linked trace polyurethane (PU) in the polymer network significantly enhances the adhesion to substrates and resistance to scrubbing for the coatings. Its amphiphilic interface and quaternary ammonium salt groups effectively inhibit the adhesion of proteins, bacteria, and diatoms. After simulated scrubbing, the coating maintains over 90% inhibition against Halamphora sp. Further investigations on mussel adhesion, including mussel’s selective attachment, removing force testing, and adhesion protein gene expression analysis, reveal that while amphiphilic interfaces induce increased expression of mussel adhesion proteins gene, mussel adhesion strength is still weakened under characteristic interface interactions. This coating features a simple preparation method, rapid curing, excellent transmittance (>85%), highly effective antifouling performance, and scrubbing resistance. It offers an innovative solution for protecting underwater transparent equipment from biofouling.