External Self-Healing Coatings in Anticorrosion Applications: A Review

Nowadays corrosion has become an urgent problem to be solved. Scientists are committed to finding various ways to restrain the corrosion of metals. The anticorrosion coating is considered to be an economical and effective method. However, the conventional anticorrosion coating is vulnerable to be damaged. The external self-healing coating can release the active healing agent when destroyed and prevent the corrosion spontaneously, which has been the subject of increasing interest. In this paper, the anticorrosion application of external self-healing coatings was described in detail, including organic micro/nanocontainer-based, inorganic micro/nanocontainer-based, and microvascular network-based self-healing coatings. First, the present article introduced the development, preparation, and self-healing properties of the external self-healing coating. In the successive chapter, the anticorrosion performance of the coating was highlighted. Also, some open problems and future challenges were also investigated. Finally, special attention was dedicated to the prospect of the external self-healing coating. This review provides readers with an overview of achievements to date and insights into the future development of engineering applications to promote the large-scale application of external self-healing anticorrosion coatings.