Dispersion properties of TiO2 nano-powder synthesized by homogeneous precipitation process at low temperatures

The dispersion stability of rutile TiO2 powder with a unique nano-structure synthesized by homogeneous precipitation process at low temperatures (HPPLT) has been investigated with adding the various electrolytes in both pure aqueous and organic media. Zeta potential measurements have shown that the addition of electrolytes such as CsCl, CaCl2, FeCl3, and ZrCl4 to aqueous and pure organic dispersion media leads to generally a charge reversal from negative to positive on the surface of TiO2 particle. The electrostatic repulsive force acting on between TiO2 particles dispersed in pure organic media was found to be significantly greater than that in aqueous media, which is closely related to the physical properties of the organic solvents, such as viscosities and dielectric constant. The surface potentials of TiO2 particles have been greatly modified by the particulate properties, pH, dispersion medium, and valence of the ionic species, which governs the colloidal behavior of TiO2 particles virtually.