PDA-modified g-C3N4 nanosheet-supported Zn/Cu-MOF for multifunctional self-healing anticorrosion coatings with UV aging resistance.

Marine structural materials are severely affected by corrosion. Epoxy resin (EP) is a common anticorrosive material for its good stability, yet single-function coatings cannot cope with harsh marine service environments. In this work, Zn/Cu-MOF was in-situ loaded on g-C3N4 nanosheets to prepare multifunctional self-healing anticorrosive coatings with favorable barrier and anti-UV aging performance. The g-C3N4@PDA@Zn/Cu-MOF particles were successfully fabricated by in-situ growth. A high |Z|0.01 Hz of 1.36 × 1010 Ω·cm2 was still maintained for the intact coating after 30-day immersion in 3.5 wt% NaCl, demonstrating superior protective performance. When damaged, Zn/Cu-MOF releases Cu2+, Zn2+ and 2-methylimidazole (Im) to form protective layers at scratches. The |Z|0.01 Hz of the scratched coating increased to 53,787 Ω·cm2 from the initial value of 35,123 Ω·cm2 after 8 h immersion, revealing favorable self-healing characteristics. Furthermore, the coating achieves outstanding synergistic antifouling performance with a Chlorella adhesion rate of only 0.14 ± 0.03%, and retains stable anti-corrosion capacity even after 168 h UV accelerated aging treatment.