Sediment-Resistant Marine Antifouling Coating Based on Amphiphilic Copolymer Brushes Bearing Sulfobetaine and Isobornyl Pendants

Abstract

For marine antifouling coatings to be practically useful, resistance to both marine fouling organisms and inorganic marine sediments is essential. Amphiphilic copolymer coatings, which integrate hydrophilic and hydrophobic components, are known to impart such dual antifouling properties to solid substrates. In these systems, the hydrophilic component functions as a physical barrier to inhibit biological fouling, while the hydrophobic component prevents the adsorption of marine sediments. Based on this principle, various amphiphilic copolymers have been developed for marine antifouling applications. To effectively minimize both biological adhesion and sediment accumulation, in addition to selecting appropriate hydrophilic and hydrophobic monomers, optimizing their relative composition is crucial. In this study, amphiphilic copolymer coatings composed of sulfobetaine methacrylate (SBMA) and isobornyl methacrylate (IBMA) are synthesized via surface-initiated atom transfer radical polymerization. Through a systematic investigation, the optimal SBMA-to-IBMA ratio is determined to achieve a balanced antifouling performance. Notably, coatings prepared with an SBMA:IBMA feed molar ratio of 1:1 effectively suppress both marine diatom adhesion and sediment adsorption. Surface free energy analysis reveals that superior antifouling performance correlates with a lower surface free energy. These findings underscore the design parameters that should be considered in the development of high-performance amphiphilic copolymer coatings for marine antifouling applications.