Bioinspired polydopamine nanosheets for the enhancement in anti-corrosion performance of water-borne epoxy coatings

The utilization of two-dimensional (2D) inorganic nanomaterials as nanofillers in the anticorrosion fields has garnered significant attention due to their exceptional barrier properties. However, uniform dispersion of nanofillers and good interfacial compatibility with organic coatings still remain a substantial challenge. Consequently, there is a need to explore novel and eco-friendly 2D nanomaterials for anticorrosive applications. In this study, two-dimensional polydopamine nanosheets (PDANS) were synthesized through a facile template method, and incorporated into water-borne epoxy (WEP) coating as green anticorrosive additives. Compared to WEP coating, the prepared PDANS/WEP coatings exhibited significantly enhanced corrosion protection performance, with a nearly 50% reduction in water uptake and a 22-fold increase in the |Z|f=0.01 Hz value at a 0.5 wt % PDANS loading. These improvements can be attributed to the favorable interfacial compatibility between PDANS and WEP matrix, as well as the superior barrier properties of PDANS. Furthermore, local electrochemical impedance spectroscopy (LEIS) results demonstrated that the damaged PDANS/WEP coating provided enhanced corrosion protection by inhibiting steel corrosion through the chelating interaction between PDANS and steel, thereby reducing the coating delamination. Based on these findings, it can be inferred that PDANS hold great promise for the development of innovative anticorrosive coatings.