Designing a high-performance waterborne epoxy coating with passive/active dual self-healing properties by synergistic effect of V2O5@polyaniline-tannic acid inhibitors

Inspirations from nature have led to extensive developments in metal passivation and smart self-healing technologies toward metal corrosion protection. Integration of both intriguing features helps to achieve high-efficiency corrosion inhibition protection. In this study, we designed a novel anticorrosion system composed of waterborne epoxy (WEP) and VPC nanofillers (V 2 O 5 modified by polyaniline and tannic acid complexes) (V 2 O 5 @PANI@Fe-TA (3)). Among them, the PANI-modified V 2 O 5 particles have dual roles as oxidation passivation protection and a passive barrier. The tannic acid corrosion inhibitor loaded onto the particles can be released under pH stimulation to provide appropriate activity inhibition function. This dual, synergistic self-healing protection coupled with a robust film barrier was the main reason for the strong anticorrosion properties of the coating system. In a specific experiment, the anticorrosion performance of the composite coatings was verified by electrochemical and salt spray tests. Results revealed that the value of |Z| 10mHz for VPC/WEP composite coating was still higher than 10 8 Ω/cm 2 after 80 d of immersion as compared to those of the pure WEP. Interestingly, the VPC/WEPs also exhibited a significant self-healing effect when the corrosive medium reached the metal/coating interface through defects or artificial scratches. This is due to the synergistic protective effect of metal passivation and activity inhibition, which enhanced the anticorrosion properties of the coating system.