Design of smart protective coatings with autonomous self-healing and early corrosion reporting properties

Highlights: • A supramolecular smart coating with early corrosion reporting and self-healing properties was developed. • The coating exhibited autonomous self-healing performance under room temperature, saltwater and hypothermia conditions. • The smart coating can locate and report the occurrence of corrosion damage. • This material is promising for steel protection and failure assessment. This work reports the design of supramolecular polyurethane coating capable of early corrosion reporting and efficient self-healing for steel protection. Immersion experiment indicates that the occurrence of early corrosion can be rapidly reported and highlighted by the formation of Phen-Fe complex with conspicuous red color. Electrochemical and mechanical tests illustrate that the prepared coating possessed autonomous self-healing under room temperature, saltwater and hypothermia conditions, which are attributed to the dynamic interactions of hydrogen bonds. Taking advantage of the merits of as-prepared coating, the metallic materials corrosion can be nondestructive detected and the damage can be autonomously repaired.