Environmentally Friendly Waterborne Polymer/Reduced Graphene Oxide Nanocomposite Anticorrosion Coatings for Q235 Carbon Steel.

Corrosion severely affects marine metallic infrastructures. Organic coatings offer a low-cost, effective solution, but their solvent-rich processing reduces sustainability. For polymer nanocomposite coatings, additional chemical modification of fillers is typically required to improve dispersibility. Herein, we report the synthesis of waterborne polymer/reduced graphene oxide (rGO) nanocomposites via a miniemulsion polymerization as an anticorrosion coating for Q235 steel. Using a vinyl copolymer based on styrene and n-butyl acrylate, we successfully formulated kinetically stable latexes with inherent film-forming ability at room temperature. The thermally annealed polymer/rGO coatings formed a uniform, defect-free layer on the steel surface without rGO agglomeration and delamination. These polymer/rGO coatings, particularly at pH 10 demonstrated electrical conductivity, mechanical robustness, and highly effective anticorrosion performance. Polymer/rGO coating of pH 10 exhibited enhanced corrosion protection after 168 h exposure to 3.5 wt.% NaCl solution ((Icorr = 0.01 µA cm-2, P.E of 99%), outperforming the corresponding pH 2, neat polymer coating, and bare metal, validated by post-immersion analysis and marine field testing. This organic solvent-free type of protective coating, comprising vinyl polymer and unmodified rGO represents a novel approach towards the development of advanced anticorrosion coating for critical metals.