Full-Ocean-Depth-Oriented Poly(oxime-urethane) Coating: Construction and Protective Mechanism for Integrated Antifouling and Anticorrosion.

Abstract

Full-ocean-depth (FOD) environment, characterized by extreme pressure, salinity, and biological complexity, presents severe challenges for surface antifouling and anticorrosion. High-performance coatings capable of withstanding such coupled extreme conditions are urgently needed. Herein, an integrated antifouling/anticorrosion poly(oxime-urethane) (PUDF) coating with a tunable microphase-separated structure was developed by incorporating the intrinsically antifouling unit (2,5-diformylfuran dioxime, DFFD) and the reactive high-barrier nanosheets (carboxyl-functionalized graphene oxide GO-COOH). The coating showed excellent biointerface resistance, suppressing protein and bacterial biofilm adhesion by 98 and 99%, respectively, and achieving 100% bactericidal efficacy against marine bacteria. After 2 months of immersion at both shallow-sea (2 m, East China Sea) and deep-sea (7730 m, Philippine Sea) sites, no macrofouling organisms or deep-sea microbial adhesion were observed. Cross-linking GO-COOH within the PUDF matrix enhanced microphase separation and mechanical robustness, enabling exceptional resistance to coupled corrosion. Under a combined condition of 15 MPa, 3.5 wt % NaCl, and 10⁶ cells mL^-1 <i>Pseudomonas aeruginosa</i>, the coating exhibited impedance two orders of magnitude higher than pristine PUDF. Microbial community analysis and density functional theory (DFT) simulations further elucidated the disruption of purine biosynthesis/nucleotide metabolism antifouling and low-adsorption/high-barrier anticorrosion synergistic protection mechanisms. This study offers a theoretical and practical basis for designing integrated protection materials for FOD applications.