Anticorrosion Self-Healing Polymer Coatings Containing Micro/Nanofibers with Core-Shell Microstructures: A Review

Traditional anti-corrosion coatings only act as a passive barrier on the metal substrate and have no active protective function if the coating on the surface is damaged. Recent smart anti-corrosion coatings can greatly increase the lifespan of the coating. On the other hand, self-healing technology in polymer coatings is a preventive method to progress of corrosion process on the surface of metals. This technique has been developed in order to prevent the growth and propagation of cracks in the early stages and to repair the damage automatically without external intervention. The increasing trend of published scientific articles shows that the use of anti-corrosion smart polymer coatings with self-healing capability has received much attention. In this type of coatings, corrosion inhibitors and healing agents can be loaded together or separately in spherical or nanofiber micro-carriers. In the case of damage of the coating surface, the anti-corrosion as well as healing processes trigger simultaneously to prevent the corrosion progress of the metal surface. The purpose of this study is to review novel epoxy-based coatings with self-healing and anti-corrosion properties. For this purpose, the self-healing mechanisms, methods of implementation of self-healing materials and anticorrosion agents on the coating have been reviewed and categorized. The use of polymer microcapsules with core-shell structures in the form of spherical particles or electrospun nanofibers in self-healing coating has been described. Various nanofiber systems have been classified in terms of the location of restorative and anticorrosion materials, the type of polymer shell and core materials, the electrospinning methods of nanofibers, and the method of dispersing within the coatings, for simultaneous anti-corrosion and self-healing properties. Finally, the recent studies on the coatings containing conductive and/or green nanofibers have been reviewed.