Correlation between the Zeta Potential and Rheological Properties of Anatase Dispersions

The viscosity at an arbitrarily selected shear rate of 1.16 s21 and
the yield stress of anatase dispersions are linearly correlated, and
both show a maximum at the isoelectric point (IEP) at pristine
conditions. The rheological properties of anatase dispersions re-
spond to the shift in the IEP to higher pH values, which is
observed in concentrated solutions of 1–1 electrolytes and in the
presence of the organic cosolvents, but the shift in the pH corre-
sponding to a maximum viscosity does not exactly match the shift
in the IEP. In contrast with the electrokinetic curves, the rheo-
logical curves at high ionic strengths are rather insensitive to the
nature of the supporting electrolyte. The acidic branch of the
viscosity(pH) curves is relatively insensitive to the ionic strength
while the slope of the basic branch decreases when the ionic
strength increases.