Chameleon skin-inspired smart coating with hierarchical self-warning/self-healing functions for sequential damage-to-corrosion protection

A smart protective coating with hierarchical self-warning and self-healing functions was developed by incorporating polyurethane/poly-(urea formaldehyde) (PUF) microcapsules loaded with anthocyanin (Anth) into a semi-interpenetrating polymer network (semi-IPN). The semi-IPN consists of hydrogen-bonded polyurethane (PU) and rigid epoxy resin (EP) network. The released anthocyanin not only provides distinct chromatic responses but also adsorbs onto the Mg surface to form protective complexes, exhibiting an inhibition efficiency of 94 %. XPS analysis elucidates the interfacial corrosion inhibition mechanism. This “one-molecule, multi-function” strategy offers a simplified method for achieving hierarchical functions against coating damage and substrate corrosion, showing significant potential for smart coatings.