C-ZIF7@Ag/EP Coating for Eco-Friendly Marine Protection: Near-Infrared-Responsive Self-Healing with High Antibiofouling Efficacy.

Marine engineering facilities face the dual challenges of biofouling and material corrosion over extended periods. Traditional antifouling coatings struggle to meet environmental and long-term service requirements due to excessive heavy metal ion release or a lack of self-healing capabilities. This study designed and prepared an epoxy resin-based coating (C-ZIF7@Ag/EP) incorporating C-ZIF7@Ag nanocomposites. By synergistically leveraging photothermal effects and controlled release of bactericidal ions, the coating achieved highly efficient antifouling and self-healing functionality. Under 808-nm near-infrared irradiation (150 s to reach 132 °C at 1.5 W cm-2), the coating rapidly heated up. The coating exhibited a reversible viscoelastic solid-liquid transformation, enabling effective healing of surface scratches upon near-infrared irradiation. Antibacterial tests demonstrated 99.1% and 99.4% kill rates against Escherichia coli and Pseudomonas aeruginosa, respectively, under near-infrared light. Marine biofouling tests confirmed significant inhibition of organism attachment, such as that by conchs. Furthermore, acidic environments (pH = 4-6) synergistically promoted the controlled release of Zn2+ and Ag+ when combined with photothermal stimulation. The release concentrations of Zn2+ and Ag+ after 30 days were 1.95 μg cm-2 d-1 and 0.06 μg cm-2 d-1, respectively, remaining within environmentally safe levels and posing no risk of marine pollution. Electrochemical impedance spectroscopy (EIS) results indicated that after 30 days of immersion in artificial seawater, the |Z|0.01 Hz value of the C-ZIF7@Ag/EP coating remained at 2.48 × 108 Ω cm2. The C-ZIF7@Ag/EP coating developed in this study offers a strategy for creating eco-friendly, long-lasting, self-healing marine antifouling and anticorrosion materials, demonstrating significant engineering application value.