Epoxy composite coating with excellent anticorrosion and self-healing performances based on multifunctional zeolitic imidazolate framework derived nanocontainers

Abstract

Zeolitic imidazole framework-8 (ZIF-8) with porous structure, pH-response and facile synthesis characteristics, as a molecule delivery and stimulus-response nanomaterial, has been widely investigated over the past decades. Here, we report for the first time a new corrosion inhibitor-encapsulated nanocontainer (denoted as HMSN-BTA@ZIF-8), successfully synthesized using ZIF-8 as self-sacrificial template, pH-responsive gatekeeper and interfacial compatibility assistant for hollow mesoporous silica nanoparticle (HMSN). Corrosion inhibitors of benzotriazole (BTA) are encapsulated in the cavity and mesopores of HMSN. The results demonstrate that there are outstanding pH-triggered activities to both acidic and alkaline conditions for HMSN-BTA@ZIF-8. Rather than physically dispersing nanocontainers in the coating matrix, the synthesized HMSN-BTA@ZIF-8 can covalently interact with epoxy resin, resulting in superior compatibility and more uniform dispersion behavior of nanocontainers in the coatings. Interestingly, the epoxy composite coating with HMSN-BTA@ZIF-8 exhibits excellent corrosion protection and outstanding self-healing performances, which are well characterized by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), salt spray test and Scanning Kelvin Probe (SKP) technique. The outstanding anticorrosion and impressive self-healing properties are attributed to the good compatibility of HMSN-BTA@ZIF-8, the hydrophobicity of ZIF-8, higher crosslinking densities, and the controllable release of BTA in the epoxy composite coating. It is believed that this work is very helpful for extending the service life of various anticorrosion coatings.