The aim of the present Project is the design and implementation of hydrophobic surfaces by using a wet chemical method known as sol-gel technology. In a first step, a deep study about an adequate selection of the different metal alkoxydes (silica precursors) have been performed. In a second step, the optimization of the specific parameters has been also evaluated for two different deposition techniques such as dip-coating and spraycoating. The most important parameters of study were the pH (catalytic action), immersion time (Dip-coating), spray-coating time and drying temperature. In order to characterize the surface coatings, several techniques have been employed such as water contact angle (WCA), UV-Vis spectra and Atomic Force Microscopy (AFM).
Finally, the experimental results corroborate that the use of silica nanoparticles make possible the design of superhydrophobic surfaces (WCA = 161º), although the transmittance values or mechanical resistance are lower. In addition, it has been found that the spray time and the drying temperature play a key and positive role in the final hydrophobic behavior in comparison with the immersion time.
Keywords: Sol-gel, hydrophobicity; Coatings; Spray-coating; Dip-coating; Nanoparticles