Thermal stability of superhydrophobic and oleophobic silica nanoparticle spray coating

Superhydrophobic surfaces are known to offer high water repellency, however many industries such as the petrochemical and automotive industry need not only water resistant surfaces but also require oil resistant surfaces. Oleophobic coatings repel/reduce adhesion of viscous liquids and oil to the surface. Nano-coatings like silica nanoparticle coatings are known to offer both superhydrophobic and oleophobic properties. In this study, we evaluated both functionalized (FSP) and non-functionalized commercial silica particles (NFSP) and functionalized silica nanoparticles (FSN). Some of the key issues with employing both superhydrophobic and oleophobic coatings are durability and thermal stability. In our studies, we assessed the thermal stability of silica nanoparticle spray coatings, targeting a thermal stability of 500 °C. Our results indicated that the FSN coating exhibited both high water (≥ 150°) and oil (≥140°) contact angle at lower temperatures (100 °C) and was thermally stable up to 400 °C, in which the WCA and OCA only decreased by 10–13 °.