Surface Characterization of Silica Modified with Aminosilane Compounds

Abstract

Adsorption behaviors, IR spectroscopy and surface electric properties were studied on the surfaces of well-defined mesoporous silica gels modified with triethoxy(3-aminopropyl)silane (TAS) and [3-(dimethylamino)propyl]diethoxymethylsilane (DDS). Surface free silanol groups react with ethoxyl groups of these compounds rigidly. Isoelectric points and points of zero charge of modified silicas shift from pH 3 of pure material to alkali, but DDS-modified silica gels dissolve themselves in aqueous phase because of their strong alkali environment.