(rutile modification) depend on the nature of the dispersion medium (water, isopropanol, and 1,4-dioxane). The
influence of pH, addition of sodium sulfate, and adsorption of poly(methacrylic acid) (the molecular mass of
120
103) on these interactions in aqueous solutions was also studied. The number of primary particles in aggregates was determined from the data of sedimentation analysis. It was shown that redispersion of the tita-
nium dioxide powder to primary particles is never complete, and this process leads to the formation of equilib-
rium aggregates, whose size depends on the nature of the dispersion medium and on the solid phase concentra-
tion. The titanium dioxide suspensions are unstable with respect to aggregation in weakly acidic media near the
isoelectric point. In contrast, the suspensions stable with respect to aggregation are formed in strongly acidic
and alkaline media, but these suspensions become unstable upon the addition of electrolyte. The suspensions
become stable upon adsorption of poly(methacrylic acid) on the titanium dioxide particles, and their stability
is retained upon the addition of electrolyte up to the concentration of 0.01 mol/l. If one assumes that the
adsorbed polyelectrolyte layers change the ion-electrostatic and dispersion components of the disjoining pres-
sure, then the experimental results agree with the DLVO theory of the aggregation stability of lyophobic
colloids.