A smart epoxy coating with self-healing and long-acting anti-corrosion capabilities via pH-responsive MIL-100(Fe) nanocontainers

To overcome the shortcomings of epoxy coatings in inadequate long-term barrier properties and lack of active corrosion inhibition at defect sites, we developed a self-healing epoxy coating by incorporating a MIL-100(Fe) nanocomposite loaded with benzotriazole (BTA), which was synthesized using solvothermal and solution impregnation methods. This multifunctional system provides robust barrier protection and alkaline-triggered self-healing capabilities. The composite enables alkaline-triggered BTA release, forming a protective film at damaged sites. The synthesized MIL-100@BTA nanocomposite exhibits a high surface area, thermal stability, and controlled BTA release. In simulated seawater, the MIL-100@BTA/EP coating maintained a low-frequency impedance modulus of 5.03 × 10⁹ Ω·cm² after 50 days, significantly outperforming pure epoxy. Scratch tests, electrochemical tests, scanning electron microscopy (SEM) and electron dispersive spectrum (EDS) analyses confirmed that the released BTA inhibits corrosion by forming a protective film at defect sites. This work presents an effective strategy for engineering high-performance and self-healing coatings.