Hybrid silica bearing different organosilanes produced by the modified Stöber method

The Stöber method was used to prepare a variety of functionalized silica through the reaction of tetraethyl orthosilicate (TEOS) and several organosilanes. The organosilanes differed in the number of carbons in the alkyl chain as well as in the functional groups. The TEOS:organosilane ratio employed was 90:10 M. The resulting materials were characterized by nitrogen adsorption-desorption porosimetry, small angle X-ray scattering, scanning electron microscopy, transmission electron microscopy, contact angle measurements and Fourier transform infrared spectroscopy. Spherical functionalized silica microparticles approximately 0.5 μm in size with increased hydrophobicity were obtained. The adsorption-desorption isotherms were independent of the nature of the organosilane employed and can be classified as type II, typical of nonporous solids. The contact angle was between 0 and 153°. The presence of organic moieties on the silica can modify the morphology and the hydrophilicity of the materials produced by the Stöber method.