Advance of design and application in self-healing anticorrosive coating: a review

As a significant method to inhibit metal corrosion by blocking the diffusion of corrosive mediums to the metal surface, the anticorrosion coating with a self-healing function can actively repair a damaged structure and improve the anticorrosion performance to better meet actual needs. In this study, "external aid " and "intrinsic triggering " self-healing coatings have been introduced in detail, including the preparation method, healing mechanism and practical applications. The healing of "external aid " is based on the addition components such as microcapsules containing healing agents and functional nanoparticles, whose ability of self-healing shows the independence with the coating resin. But the finitely additive amount may limit the sustainable use of "external aid " components, and the abundant fillers also change the basic physical properties of the coating. On the contrary, the "intrinsic triggering " resins can form the cover layer in the defects owing to the physical or chemical reactions between the polymer chains, along with the unlimited cycles theoretically. By contrast, the small defects or gaps can be repaired gradually through chain reactions, but the large areas of damage may need the quick release of healing additives in "external aid " coating. In this review, the advances of two kinds of self-healing coatings were analyzed to discuss the advantages and disadvantages of various healing technologies, and the challenges of development and prospects were also forecasted to provide useful ideas. [Graphics]