A self-healing epoxy composite coating based on pH-responsive PCN-222 smart containers for long-term anticorrosion of aluminum alloy

A novel pH-responsive smart container system has been developed using the metal-organic framework PCN-222 for the purpose of self-healing anticorrosion coating on Al alloy. The inhibitors 8-hydroxyquinoline (8-HQ) incorporate with PCN-222 by binding tightly to Zr6 clusters and porphyrin of PCN-222 via hydrogen bonding and π-π stacking, ensuring high loading and pH-triggered release activity. Additionally, PCN-222 interacts covalently with epoxy resin, prompting the dispersion of 8-HQ@PCN-222 and crosslinking of the epoxy coating. The resulting 8HQ@PCN-222 composite provides good compatibility with epoxy resin and impressive self-healing performance, all of which contribute to the long-lasting anticorrosion ability of the composite coating.