Photothermal-Activated Self-Healing Polyurethane for Comprehensive Marine Protection Integrating Antifouling and Anticorrosion Functions

The protection of metallic equipment in marine environments demands integrated solutions that combine corrosion and fouling resistance with self-healing functionality to ensure long-term reliability. This study presents a self-healing integrally antifouling and anticorrosion coating (SIAAC) exhibiting rapid photothermal response and superior protective performance. The composite coating (STPUa-BPGO) achieves efficient photothermal conversion, exceeding 80°C within 3 min under near-infrared (NIR) light irradiation, and demonstrates a healed efficiency of 90.29% after 10 min with excellent repeatability. The anticorrosion is achieved by the shielding effect of dopamine-coated and reduced graphene oxide (PGO) within the matrix. After 30 d of immersion in 3.5% NaCl solution, the |Z|_0.01 Hz value of STPUa-BPGO remains as high as 2.80 × 10⁸ Ω cm², effectively integrating photothermal self-healing with shielding anticorrosion. Additionally, the antifoulant 1,2-benzisothiazol-3(2H)-one is controlled for release by hydrogen bonding, inhibiting bacteria and algae coverage by 97.66% and 2.15%, respectively. Marine field tests further confirm its efficacy in preventing biofouling. By synergistically incorporating self-healing, anticorrosion, and antifouling properties, STPUa-BPGO presents a robust and multifunctional coating system for the protection of marine metallic structures.