Effect of anilines as a synthesis component on the hydrophobicity of silica

Abstract

This chapter investigates the grafting process on silica prepared by sol–gel. The principle of the investigation work consists in comparing the grafting of anilines, with different active groups, on silica to obtain different degree of the surface hydrophobicity. For a better understanding of these solids, the characterization of the nature of the species was determined by Fourier transform–infrared (FT–IR), X-ray diffraction (XRD), differential thermal analysis–thermal gravimetric analysis (DTA–TGA), and surface area (SBET). The results showed that the main differences between functionalized silica spectra and that of the pure silica are due to the N–H stretching band and overtone band. Two possible vibrational bands are—asymmetrical –NH3+ bending band and the symmetrical –NH3+ bending band. The mode of anchorage of the organic compounds is of prime importance for the characteristics of the final functionalized silica. After functionalization, it the degree of hydrophobicity of silica surface was determined with water and wettability with ethanol, respectively.