Designing green self-healing anticorrosion conductive smart coating for metal protection

The development of an electrically-conductive anticorrosion coating with self-healing capability for metallic surface protection constitutes a priority concern for many key industrial applications. While current technologies largely rely on hazardous chromate-based corrosion inhibitors, this work proposes a simple polymer-based layer-by-layer (LBL) architecture, implemented using easy and fast fabrication techniques. Moreover, this smart coating architecture relies on three environmentally friendly polymers namely polyethylenimine (PEI), polystyrenesulfonate (PSS) and 8-hydroxyquinoline (8HQ) respectively serving as poly-cation, poly-anion and as corrosion inhibitor. Here, this protective coating is deposited and tested on the widely-used Aluminium 2024 alloy to achieve long term protection against corrosion. When structural damages to the coating occur, the inhibitor agents are released to passivate the surface. Raman micro-spectroscopy measurements confirm this effective self-healing capability. This chromate-free coating shows great promises for multiple aerospace, construction and automotive applications.