Stability Calculations of TiO2 Nonaqueous Suspensions: Thickness of the Electrical Double Layer

Abstract Stability behavior of TiO 2 particles dispersed in n -hexane in the presence of butylamine was investigated by turbidity and electrokinetic measurements. TiO 2 A particles were dried at 150°C and n -hexane was treated with 3 A molecular sieves to remove any trace of water. The inorganic particles were found to be negatively charged in the amine concentration range 10 -5 -10 -1 M . The magnitude of zeta potential was found to increase with amine concentration and becomes constant at the butylamine plateau adsorption. DLVO theory was applied to the present system in order to estimate the thickness δ of the electrical double layer surrounding the solid surface. Experimental stability/flocculation behavior of the system was in a good agreement with that predicted by DLVO theory. The interaction energy calculations gave a critical δ value, below which flocculation was observed, but above which the system remains stable. Our investigations show the existence in nonaqueous dispersion of an electrical double layer having a finite thickness.