Dual-Action Intelligent Self-Healing Waterborne Epoxy Coatings Enabled by 2D Leaf-Like ZIF-L Nanocontainers for Corrosion Protection

Integrating robust physical barrier properties with efficient self-healing capability is widely recognized as an effective strategy for developing long-term anticorrosive coatings. In this study, a pH-responsive multifunctional nanocontainer, denoted as ZIF-L-BTA@PDA (ZBP), was rationally designed through in situ encapsulation of benzotriazole (BTA) within two-dimensional leaf-like ZIF-L, followed by dopamine (DA) self-polymerization to form a polydopamine (PDA) shell on the ZIF-L-BTA surface. The resulting ZBP nanocontainers were uniformly dispersed in a waterborne epoxy (WEP) matrix to fabricate a composite coating with enhanced barrier performance, intelligent self-healing behavior, and improved interfacial compatibility. In this system, ZIF-L serves a dual function as both an inhibitor reservoir and a high-aspect-ratio barrier filler, effectively prolonging diffusion pathways for corrosive species. The PDA shell endows the nanocontainer with pH-triggered BTA release behavior, additional self-healing capability, and the improved compatibility with the epoxy matrix. Release studies confirmed the pH-responsive characteristics of the ZBP nanocontainers. After 40 days of immersion in a corrosive medium, the ZBP/WEP coating maintained a low-frequency impedance modulus (|Z| 0.01Hz ) value of 1.08 × 10 10 Ω·cm 2 , approximately three orders of magnitude higher than that of pure WEP (1.34 × 10 7 Ω·cm 2 ), corresponding to an anticorrosion efficiency of 99.99%. The self-healing performance of ZBP/WEP was further validated by artificial scratch test. This work provides a promising strategy for designing high-performance, intelligent self-healing coatings for long-term corrosion protection.