Influence of Solids Concentration on the Isoelectric Point of Aqueous Barium Titanate

Abstract

We report on findings that the particle surface charge is influenced by solids concentration in aqueous suspensions of BaTiO 3 . Three decades in solids concentration were analyzed by combining results from two different electrokinetic methods. Combined results demonstrate a systematic acidic shift in the isoelectric pH with decreasing solids concentration. The shift is attributed to the development of a Ba‐depleted, TiO 2 ‐rich surface layer. Using kinetic arguments, it is shown that the thickness of this layer will be proportional to the surface‐to‐volume ratio.