A performance and eco-friendly bio-inspired waterborne anti-corrosion composite coating by low-defect PDA@g-C3N4 nanosheets

Due to the low volatile organic compound (VOC) emissions, waterborne coatings are gaining much attention. However, the weak barrier properties prevent them from being practical. In this study, a novel well-dispersed low-defective the g-C3N4 nanosheets are successfully prepared using urea and polydopamine, followed by the preparation of an extensible bio-inspired coating. The bio-inspired coating comprises of PDA@g-C3N4 nanosheets that are oriented and possess zigzag channels, rendering them impervious to corrosion factors. Electrochemical tests have demonstrated that the bio-inspired coating displays a substantially improved resistance of 1.18 × 1010 Ω cm2, surpassing the pure epoxy coating (6.77 × 107 Ω cm2) by three orders of magnitude. Moreover, the excellent corrosion resistance of the bio-inspired coating has been substantiated through salt spray tests. The development of bio-inspired composite coatings presents a novel avenue for investigating the synthesis of waterborne epoxy coatings with exceptional performance.