High‐performance self‐healing anticorrosion epoxy coating based on microencapsulated epoxy‐amine chemistry

Abstract Attributed to the merits of excellent material compatibility, healing performance, and long‐term stability, the self‐healing system based on microencapsulated epoxy‐amine chemistry is a potentially practical self‐healing system for both structural and functional materials. Herein, based on the microencapsulated epoxy‐amine chemistry, a self‐healing anticorrosion coating was successfully developed. This self‐healing coating system was modeled theoretically to explore the factors that influence the crack filling and the self‐healing anticorrosion function. The established quantitative relationship shows that the filling depth of the crack in the coating is proportional to the microcapsule parameters and coating thickness, but inversely proportional to the crack width. Based on the above theoretical model, the effects of various parameters on the anticorrosion performance were experimentally studied. The actual filling of small in‐situ cracks (<100 μm) generated by impact damage was semi‐quantitatively characterized using scanning electron microscopy (SEM). The filling behavior is consistent with the theoretical modeling. After being healed at room temperature for 2 days upon impact damage, the formulated self‐healing coatings were subjected to accelerated corrosion tests in 10 wt% sodium chloride (NaCl) solution for 2 days to observe their anticorrosion behavior. Compared to the neat epoxy coating, all the formulated self‐healing epoxy coatings show evident anticorrosion function. Good self‐healing anticorrosion performance was achieved by adding 10.0 wt% microcapsules with a size of 100–150 μm to the coating with a thickness of 300 μm. The results of this investigation laid a theoretical and technical foundation for the further development of both the self‐healing chemistry and the self‐healing anticorrosion coating.