Naringin–functionalized thiourea@ZIF–8/graphene oxide filler for an intelligent self–healing coating with excellent anticorrosion and antibacterial properties

To enhance the long-term protective efficacy of epoxy resin (EP) coatings, this study prepared naringin (Nar)-functionalized thiourea (TU)@ZIF-8/graphene oxide (NTZG) nanoparticles via in situ growth coupled with self-assembly and used these nanoparticles to prepare a pH-responsive modified EP coating. The uniformly dispersed particles considerably improved the protective efficacy of the coating, reducing the water absorption rate to 1/56 that of pure EP coating. After 90 d of coating corrosion resistance testing, the impedance modulus of the NTZG/EP coating at 0.01 Hz remained above 10 8  Ω·cm 2 , whereas the pure EP coating lost its protective capability. The release of TU and Nar from damaged sites on the coating effectively suppressed corrosion. Simultaneously, the released agents exhibited a synergistic effect with Zn 2+ generated through ZIF-8 degradation, producing potent antibacterial effects by disrupting the membrane structures of bacteria and inhibiting the activity of enzymes. Experimental studies combined with quantum chemical calculations showed that strong molecular interactions between TU and Nar effectively inhibited the penetration of media into the damaged coating area. Thus, the proposed strategy shows promise for the design of multifunctional smart protective coatings suitable for harsh energy production environments.