The fabrication of water- proof nanometric coatings based on organosilane compounds and their Hydrophobicity characteristics

Wetting behavior of solid surfaces is a key concern in our daily life as well as in engineering and science. In the presentresearch work, water repellent silica films are prepared on glass substrate at room temperature by sol–gel process. Thecoating sol was prepared by keeping the molar ratio tetramethoxysilane (TMOS), methanol (MeOH), water (H2O)constant at 1:14.8:4, respectively, with 2 M CH3COOH throughout the experiments and the molar ratio (S) ofDMOAP/TMOS was varied from 0 to 0.12. A simple dip coating technique is adopted to coat silica films on the glasssubstrates. The best film with transparency of 88.5% and contact angle of 104° was obtained by alcosol with molar ratioof 0.12 for DMOAP/ TMOS. The silica films were characterized by water contact angle measurements (CA), ultravioletvisible spectroscopy (UV-VIS), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM),fourier transform infrared (FT-IR) spectroscopy, simultaneous thermal analysis (STA), Dynamic light scattering(DLS).