Influence of Perfluorooctanoic Acid on Structural, Morphological, and Optical Properties of Hybrid Silica Coatings on Glass Substrates

In recent years, various coatings based on fluorinated materials, used in a commercial application, have been created through many preparation routes. However, the techniques utilized to realize these coatings required either expensive and complex equipment, imply multiple manufacturing steps, or are time- or cost-consuming. In this paper, the major target was to develop fluorinated hybrid coatings presenting sustainable hydrophobicity and good transparency simultaneously. The sol–gel method was proposed to obtain these fluorinated hybrid coatings because it does not require expensive equipment, or the existence of stabilizing agents that reduce the storage period, it consumes less energy, and it is easy to implement. The influence of perfluorooctanoic acid, utilized in the sol–gel processing of hybrid silica materials, on the structural, morphological, and optical properties of coatings deposited on glass substrates, was evaluated. Different silane precursors (tetraethyl orthosilicate (TEOS), triethoxymethylsilane (MTES), and trimethoxyhexadecylsilane (HDTMES)) were utilized to synthesize hybrid silica materials. The properties of the obtained materials were characterized by FTIR, UV–Vis, TEM, TGA, AFM, Ellipsometry, and Contact Angle analyses. FTIR spectroscopy shows the formation of a silica network tailored with organofunctional and fluoroalkyl groups. The fluorinated silica coatings presented smooth surfaces and good transparency, with a transmittance of ~90% in the visible range. It was found that the fluorinated silica materials improved the coating’s hydrophobicity (~110° in contact angle with water). These fluorinated silica materials can create multifunctional structures with antireflective and hydrophobic coatings for possible optical devices.