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

ABSTRACT 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 × 10 8 Ω cm 2 , effectively integrating photothermal self‐healing with shielding anticorrosion. Additionally, the antifoulant 1,2‐benzisothiazol‐3(2 H )‐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.