UV-Triggered Cross-Linking of Zwitterionic Polymer Coatings for Robust Marine Antifouling Applications

In the field of antifouling coatings for ships, zwitterionic polymer coatings frequently exhibit low adhesion strength and inadequate durability due to high water absorption. In this study, a photo-cross-linkable polymer chain, composed of butyl acrylate (BA), sulfonated betaine vinyl imidazole (SBVI), and 4-benzoylphenyl acrylate (BPA), remains un-cross-linked during synthesis. Upon exposure to mild ultraviolet (UV) irradiation, these copolymers can covalently graft onto substrates, enhancing their mechanical properties, including a high shear strength of 293 kPa and an excellent adhesion grade to 5B. Laboratory tests demonstrated that the antifouling capacity against BSA and lysozyme improved with an increasing content of SBVI, thereby confirming the efficacy of zwitterionic coatings in resisting early-stage fouling agents. The polymer coatings exhibited excellent resistance against bacteria and diatoms. Additionally, they effectively prevent biofilm formation and mussel adhesion. These coatings are straightforward to manufacture and demonstrate exceptional antifouling capabilities, providing a viable solution for long-term antifouling protection in marine infrastructure.