Surface morphology properties and antifouling activity of Bi₂WO₆/boron-grafted polyurethane composite coatings realized via multiple synergy

An inorganic–organic composite coating is an effective way to solve the issue of marine organism attachment and realize multi-element synergistic antifouling. Herein, Bi₂WO₆/boron-grafted polyurethane composite coatings (BWOB) composed of Bi₂WO₆ with three morphologies (nanosheet, flower and microsphere) and boron-grafted polyurethane (ITB) were successfully synthesized to achieve high-efficiency antifouling. Bi₂WO₆ nanoparticles were evenly distributed on the surface and inside the ITB to form micro/nanostructures. In the composite coatings doped with flower-shaped Bi₂WO₆, BWOB-5 showed excellent antibacterial and antidiatom adhesion properties, achieving 95.43% and 98.38% against Escherichia coli and Staphylococcus aureus, respectively, and 98.62% against Nitzschia closterium. In addition, the micro/nanostructure on the surface, the stable production of hydroxyl radicals (·OH) and superoxide radicals (·O₂^–) during photocatalysis, and the antifouling functional groups of the resin matrix in the BWOB composite coatings were all conducive to photocatalytic antifouling activity. More importantly, BWOB coatings exhibited excellent environmentally friendly properties. Therefore, BWOB coatings are expected to have potential application value in the field of photocatalytic sterilization and antifouling.