Long-Term Anticorrosion Properties of Waterborne Epoxy Coatings by Incorporating Polydopamine-Functionalized MoS2@Vanadate-Intercalated ZnAl LDH Nanomaterials

Although incorporating nanomaterials into waterborne epoxy (WEP) coatings can enhance their barrier properties and corrosion resistance, the apparent agglomeration of nanomaterials and their poor compatibility with WEP inevitably constrain the service life and industrial applications of coatings. Herein, a multifunctional nanomaterial has been successfully prepared to improve the anticorrosion performance and service life of WEP coating. When polydopamine (PDA) is used to modify molybdenum disulfide (MoS2), the abundant catechol groups on the surface of PDA-MoS2 nanomaterials can effectively chelate metal ions, thus in turn providing active sites for the growth of layered double hydroxides (ZnAl LDH-VOx). Through this efficient design, PDA-MoS2@ZnAl LDH-VOx nanomaterials are uniformly dispersed in WEP, and the PDA-MoS2@ZnAl LDH-VOx/WEP composite coating exhibits high anticorrosion performance with a low-frequency impedance (|Z|0.01 Hz) of 7.65 × 1010 ohm·cm2 in 3.5 wt % NaCl solution after Day 180. The enhanced |Z|0.01 Hz value of the scratched PDA-MoS2@ZnAl LDH-VOx/WEP composite coating indicates its self-healing property. Moreover, PDA-MoS2@ZnAl LDH-VOx nanomaterials enhance the abrasion resistance of the WEP coating, thus contributing to the long-term service life of the coating. In the WEP coating, PDA-MoS2@ZnAl LDH-VOx nanomaterials not only improve its barrier properties but also endow it with a Cl– trapping effect and self-healing properties. This study provides new insights into the design of nanomaterials with multiple functions and the development of WEP composite coatings with long-term anticorrosion performance.