Antireflective coating based on TiO2 nanoparticles modified with coupling agents via acid-catalyzed sol-gel method

Abstract TiO 2 – based materials were synthesized via acid-catalyzed sol-gel method using tetraethoxysilane (TEOS) and/or methyltriethoxysilane (MTES) - as silane coupling agents. The physical and chemical properties of the obtained TiO 2 – based materials were characterized through FT-IR and UV–Vis spectroscopy, TGA, AFM analysis and contact angle measurements. FT-IR spectra demonstrated that the silane coupling agents react via a cross-link and covalently bond on the TiO 2 surface. TGA analysis of samples was used to investigate the effect of addition of silane precursor into the TiO 2 matrix. Diffuse reflectance spectra revealed that the addition of silane agents improved the antireflective properties of obtained thin films. Water contact angle of TiO 2 - based materials showed that the wettability of the thin films was influenced by the addition of TEOS and/or MTES during the modification process. AFM images showed smooth surfaces (RMS roughness up to 3 nm) but with morphological peculiarities depending on the chemical modification, with TEOS, MTES or both, of the TiO 2 parental matrix. Transparent and hydrophobic coatings were obtained with MTES addition in the modification process of TiO 2 nanoparticles via acid-catalyzed sol-gel method.