Smart Coating of Carbon Steel Using Polystyrene Clay Nanocomposites Loaded with Cerium and Silanol Inhibitors: Characterization and Electrochemical Study

Local Khulays clay was modified to prepare polystyrene clay nanocomposite (PCN) coatings on carbon steel. The PCN coatings were added to microcapsules (MCs) loaded with the corrosion inhibitor PCN(MC). The microcapsules were prepared by the encapsulation of rare-earth metal Ce+3 ions and isobutyl silanol into polystyrene via the double emulsion solvent evaporation (DESE) technique. From characterization techniques, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) with EDX. SEM and FT-IR confirmed the success of the preparation of the PCN(MC). Nanoindentation tests were performed on the thin-film samples. A significant reduction in both the hardness and the reduced modulus was observed for the PCN film compared to the PS film. Electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) all showed an enhanced protection efficiency (%PE) of 3% PCN(MC) over 3% PCN at high temperatures and at different times. The smart coatings were proven by applying the thermal and the mechanical triggers for the 3% PCN(MC) coating. The mechanism of the release of inhibitors was discussed. The self-healing properties of 3% PCN(MC) were evaluated. The enhanced properties of the developed PCN(MC) coatings make them attractive for potential applications in the oil and other industries.