A study on functionalization process of silicon dioxide nanoparticles for hydrophobic coating applications

Functionalized nano-SiO₂ is an inorganic compound that exhibits hydrophobic properties upon the addition of a silane group through a chemical reaction. This property is highly effective in surface modification for various substrates, including glass, metal, and ceramics. These surface modifications find applications in self-cleaning, anti-fogging coatings, and water-repellent materials. In this work, the role of nano-SiO₂ and Hexadecyltrimethoxysilane (HDTMS) functionalized nano-SiO₂ has been synthesized successfully by the sol–gel method for coating applications. The outcomes of water contact angle (WCA), analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), scanning electron microscope (SEM), and transmission electron microscope (TEM) observations revealed the successful grafting of hydrophobic long-chain alkyl groups from HDTMS onto the surface of SiO₂ nanoparticles. Notably, when the ratio of SiO₂ nanoparticles to HDTMS is 0.25:1, the WCA of the functionalized SiO₂ nanoparticles is enhanced significantly. This value is 5.35 times greater than the initial angle of contact before the modification, leading to the achievement of a super hydrophobic property.