Growth of TiO2 nanocrystals in the presence of alkylpyridinium salts:: the interplay between hydrophobic and hydrophilic interactions

TiO2 nanoparticles were prepared by combining a sol-gel precipitation with growth steps performed in the presence of cationic surfactants, dodecylpyridinium chlorides (DPC), and cetylpyridinium chlorides (CPC). Solutions at concentrations pertaining to the existence of either surfactant monomers or aggregates (micelles) were employed. XPS analyses were performed both on the surfactant salts and on the aged, dried precursors to study the surfactant films adsorbed onto the oxide. The crystal structures of the calcined samples and the phase composition were examined by X-ray diffraction. The role played by the presence of the surfactant in affecting the physicochemical properties of the powders is discussed. Copyright (C) 2006 John Wiley & Sons, Ltd.