Study the effect of adding Oleic acid to reduce the medium diffusion in pores of hybrid silica-based sol-gel coatings

Due to the wide-ranging of preservative surfaces applications, there is a need for a fundamental understanding of not only how to produce such exceptional surfaces but also to know how specific surface properties affect coatings pore wettability, for example, morphology and chemical comprehending. Silica-based hybrid coatings as advanced hybrid polymers have been shown to exhibit excellent chemical stability with a chance to functionalize combined with reducing the corrosion of metal substrates. However, researches show that sol-gel only has some limitations in terms of the period of anti-corrosive properties due to the high porosity. Therefore, this work will report the preliminary performance of the diffusion prevention in a silica-based hybrid sol-gel coating that has been enhanced by adding Oleic acid (OA) to the sol-gel formula. The evaluation of the effect of the adsorption mechanism of OA on aluminium alloys surface was studied based upon using infrared analysis (FTIR) as a non-destructive test separately. The chemical confirmation of adding OA to Sol-gel was done by infrared spectroscopy (ATR-FTIR) and supported by analyzing the morphology of the surface by using scanning electron microscopy (SEM) and water contact angle test (WCA). Furthermore, the coatings' corrosion performances were studied using electrochemical impedance spectroscopy (EIS) and Potential-dynamic polarization scanning (PDPS). As a result, the Oleic acid - silica-based hybrid coating exhibited exceptional functionalized pore-blocking, hydrophobic and anti-corrosion properties, providing mimicked active protection on the aluminium alloy 2024-T3 samples compared to sol-gel-only and non-coated samples.