Rheology of Titania Based Ceramic Nanodispersions Stabilized by Cationic Comb Copolymers

Rheological studies of the ceramic based concentrated titania nanoparticle dispersions showed a clear correlation between molecular structure of the cationic polymers used as dispersants and the viscosity of the slurries. Dynamic viscosity of the electrostatically stabilized alkaline (pH 10.0) dispersions of the bare titania nanopowders with a solid loading of 15 – 25 wt.% was rather high (about 1 Pa·s) and the dispersions exhibited shear-thinning flow behavior. For electrostatic and steric stabilization of the concentrated ceramic nanodispersions of titania in alkaline conditions, the dispersions were treated with cationic comb copolymers differing in charge density and the length of PEO side chains. The dispersions treated by the cationic comb copolymers acted as the Newtonian fluids at low and medium shear rates (< 200 s-1) and showed shear-thickening flow behavior at higher shear rates. Dynamic viscosity of the dispersions with a solid loading of 15 – 25 wt.% treated by the cationic comb copolymers was very low (2 to 30 mPa·s).