TiO2 is of considerable interest as a white pigment base material due to its diverse application in a large number of products. For enhanced pigmentary product durability the surface is coated with inorganic layers of silica, alumina or zirconia or combinations there of, to mask its deleterious photcatalytic behaviour. Pigmentary TiO2 are particles of colloidal dimensions (250-350 nm) in size with large surface area to mass ratio that accentuates the propensity to form aggregates during aqueous processing due to attractive particle interactions. The aggregation of TiO2 particles during the inorganic deposition process results in the formation of unwanted encapsulated aggregates. Aggregate formation in pigmentary products impacts on key properties including gloss, opacity, hiding power and storage stability. Polymeric dispersants are extensively used for electro-steric the stabilisation of colloidal dispersions, whereby their adsorption provides an interaction energy barrier to aggregation via attractive van der Waal forces.

In the present work, the use and properties of low molecular weight polymeric dispersants (polyacrylic acid (PAA), poly(butadiene-maliec acid) (PBMA), polyphophate (PP), poly(ethylene glycol) (PEG) and polyacrylmaide (PAM) in modifying TiO2 dispersion behaviour have been investigated. Polymer charging and zeta potentials and dispersion rheological behaviour have been probed. The results show that solution/dispersion pH and polymer structure type had a pronounced effect on the interfacial chemistry and concomitant particle interactions. Rheological measurements indicate that both electrostatic and steric mechanisms played significant roles in the TiO2 state of dispersion.