Abstract: Although extremely challenging, it is highly desirable to develop self-healing materials that exhibit high efficiency under environmental conditions for marine protection applications. In this work, polyurethane elastomers with hydrogen bond and dimethylglyoxime-urethane (DOU) coordination complex were combined with in-situ dual-functional BiOI@Bi₂S₃ to synthesize high-efficiency photothermal cyclic self-healing antibacterial coating. The photothermal efficiency of BiOI@Bi₂S₃ is improved by 38% through interfacial regulation. BiOI@Bi₂S₃/PU rapidly rises by 50.2 °C within 300 s under near-infrared (NIR) light, which can trigger the hydrogen bond of polyurethane coating and recover the barrier properties of the coating through self-healing. Density functional theory was used to simulate and analyze the generation of multiple electron transfer paths after the vulcanization of BiOI, which improves the interfacial mobility of photogenerated carriers and generates more heat. Importantly, molecular dynamics verified the self-healing mechanism of hydrogen bond and the photothermal lifting mechanism of the coating. After 5th scratches and self-healing cycle tests, the coating has a self-healing efficiency of more than 80%, which can ensure the self-healing and anticorrosion protection performance of the coating for multiple cycles. The photocatalytic and photothermal properties of BiOI@Bi₂S₃ enhance the antibacterial rate of the coating up to 99%. This work provides heuristic perspectives for the design of coatings with anti-corrosion, antibacterial and self-healing properties.

Key words: Self-healing, Photothermal, Interfacial regulation, Dual-functional BiOI@Bi₂S₃, Antibacterial