Advanced materials based on covalent organic frameworks: Multi-protective coatings with anti-UV aging, enhanced adhesion and self-healing abilities

Covalent organic frameworks (COFs) show great promise for anti-corrosion due to their highly ordered structure, robust covalent network, and tunable porosity. In this paper, benzotriazole (BTA) was first loaded onto COFs, then used interface-induced polymerization to grow polydopamine (PDA) at COFs, and finally established an in situ anchored connection with the natural compound aloe emodin through adhesive bridging effect. The modified COFs were added as fillers to organic resins, obtaining organic coatings with anti-UV aging, enhanced adhesion, and self-healing abilities. Electrochemical impedance spectroscopy (EIS) revealed that within 7 days immersion, the |Z| 0.01Hz of the prepared coating was two orders of magnitude higher than that of the blank coating, and it exhibited a tendency to rebound, indicating self-healing properties. The adhesion of the prepared coating increased by 165 % compared to the blank coating. Moreover, after a 1000 h UV aging test, the prepared coating retained its self-healing abilities and surface properties. The findings show that preparation can provide effective multiple protection for coatings in complex environments. This study presents a novel approach for utilizing COFs as multi-protective fillers.