Chitosan-Tannic Acid-Encapsulated Polydopamine Nanocontainers for pH-Responsive Self-Healing Waterborne Epoxy...

Waterborne epoxy coatings are distinguished by their eco-friendly properties and low volatile organic compound emissions. However, conventional waterborne epoxy coatings often exhibit insufficient barrier performance and weak self-healing capability, resulting in poor long-term anticorrosion efficiency. To address these drawbacks, this work synthesized a novel MPDA@8-HQ@CS-TA composite, aiming to fabricate a high-performance coating with improved anticorrosion properties, pH responsiveness, and UV weathering resistance. EIS results revealed that the MPDA@8-HQ@CS-TA composite-modified waterborne epoxy coating exhibited remarkably improved barrier performance and self-healing ability. After 40 days of immersion in a corrosive medium, the impedance modulus of the MPDA@8-HQ@CS-TA composite-modified waterborne epoxy coating remained at 5.75 × 10⁸ Ω·cm², significantly outperforming that of the pure epoxy coating (1.227 × 10⁶ Ω·cm²). Driven by the decomposition of the CS-TA encapsulation layer, the MPDA@8-HQ@CS-TA composite-modified waterborne epoxy coating also presents remarkable pH-triggered release behavior under acidic conditions. The results from salt spray and ultraviolet accelerated aging trials validate the outstanding weatherability and sustained anticorrosion properties of the developed coating system. This work proposes a promising method for the preparation of sustainable and eco-friendly intelligent anticorrosion coatings.