Smart self-healing coating based on the covalent organic frameworks (COF LZU-1) for corrosion protection of steel

COF LZU-1 has the characteristics of a porous structure, a large specific surface area, and good chemical stability. In recent decades, extensive research has been conducted on its use as a nanomaterial for drug loading and separation. Here, we report a new corrosion inhibitor encapsulated nanostructure (LZU-1 @BTA). We synthesized LZU-1 via a hydrothermal method and loaded benzotriazole (BTA) corrosion inhibitor into LZU-1. The results show that loaded BTA can achieve effective pH-responsive release under acidic and alkaline conditions. The amino group present in the LZU-1 molecule can cross-link with epoxy resin, and its compatibility allows for good dispersion in epoxy resin without any further modification. The LZU-1 @BTA modified epoxy coating has shown remarkable anti-corrosion properties and excellent self-healing capabilities, which have been evaluated through various techniques such as potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), local electrochemical impedance spectroscopy (LEIS), scanning Kelvin probe (SKP) and salt spray testing. The high-quality dispersion of LZU-1 @BTA in the resin, the high cross-linking density, and the pH-responsive release of BTA in the epoxy resin are some of the key factors that contribute to the excellent anti-corrosion performance of the epoxy resin composite coating. This research has opened up new possibilities for designing anti-corrosion coatings with significantly better corrosion resistance.