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

• Published in: Corrosion science 2023-08, Vol.221, p.111318, Article 111318
• Main Authors: Ren, Shucheng, Meng, Fandi, Li, Xiaoming, Cui, Yu, Liu, Rui, Liu, Yongli, Hu, Xianwei, Liu, Li, Wang, Fuhui
• Format: Article
• Language: English
• Subjects: Corrosion protection; Epoxy coatings; PCN-222; Self-healing; Smart containers
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2023.111318

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. [Display omitted] •8-HQ@PCN-222 is a pH-responsive system for filling long-term anticorrosion coating.•Two roles of PCN-222: store/controllably release 8-HQ, covalently interact with epoxy.•DFT computations reveal H-bonding and π-π stacking bind 8-HQ and PCN-222.•8-HQ@PCN-222/epoxy coatings exhibit excellent self-healing performance.