Sea Anemone-Inspired Fluorosilicone Polyurethane Coating with Synergistic Low-Surface-Energy and Cationic Antibacterial Action for Static Antifouling

Conventional polydimethylsiloxane (PDMS)-based antifouling coatings, despite their inherent fouling-release capability, exhibit critically insufficient antifouling performance under static seawater conditions. Inspired by the synergistic physical–chemical defense strategy of sessile marine organisms, specifically sea anemones, which combine a physical mucus barrier with antimicrobial peptide secretion, the present work develops a multi-mechanism hybrid coating—designated as sea anemone-inspired fluorosilicone polyurethane—that integrates low-surface-energy physical antifouling and cationic antibacterial chemical antifouling. This coating system is constructed from silicone polyurethane (PDMS-PU), a cationic antibacterial moiety (PDMS-N+), and fluorinated functional monomers. Through systematic compositional optimization, an optimal formulation (P-4) is identified, which achieves a fracture elongation of 78.19%, a normal adhesion strength of approximately 2.5 MPa, a water contact angle of 120°, and a surface energy of 12.86 mN/m. Notably, its antibacterial rates against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) exceed 95%. The resultant coating uniquely synergizes low surface energy, potent antibacterial activity, excellent mechanical properties, and thermal stability, thereby enabling long-term and stable antifouling performance in static seawater environments. This work provides a crucial technological foundation for the engineering application and industrialization of green, durable marine antifouling coatings.