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 funda- 17 mental understanding of not only how to produce such exceptional surfaces but also to know how 18 specific surface properties affect coatings pore wettability, for example, morphology and chemical 19 comprehending. Silica-based hybrid coatings as advanced hybrid polymers have been shown to 20 exhibit excellent chemical stability with a chance to be functionalised combined with reducing the 21 corrosion of metal substrates. However, research shows that sol-gel only has some limitations in 22 terms of anti-corrosive properties due to the high porosity. Therefore, this work will report the pre- 23 liminary performance of the diffusion prevention in a silica-based hybrid sol-gel coating that has 24 been enhanced by adding Oleic acid (OA) to the sol-gel formula. The evaluation of the effect of the 25 adsorption mechanism of OA on aluminium alloys surface was studied based upon using infrared 26 analysis (FTIR) as a non-destructive test separately. The chemical confirmation of adding OA to Sol- 27 gel was done by infrared spectroscopy (ATR-FTIR) and supported by analysing the morphology of 28 the surface by using scanning electron microscopy (SEM) and water contact angle test (WCA). Fur- 29 thermore, the coatings’ corrosion performances were studied using electrochemical impedance 30 spectroscopy (EIS) and Potential-dynamic polarisation scanning (PDPS). As a result, the Oleic acid 31 - silica-based hybrid coating exhibited exceptional functionalised pore-blocking, hydrophobic and 32 anti-corrosion properties, providing mimicked active protection on the aluminium alloy 2024-T3 33 samples compared to sol-gel-only and non-coated samples.