Shear rate-dependent structure of polymer-stabilized TiO₂ dispersions

Opacity, gloss, stability, color acceptance, and other paint properties depend on the quality of pigment dispersion. We measured the shear rate-dependent structure of titanium dioxide (TiO₂) dispersions stabilized with commercial polymer dispersants in water. Two different MW polyacid dispersants and two different MW acrylate copolymers were used in this study. The experiments were conducted at the NIST Center for Neutron Research on the perfect crystal diffractometer for ultra-high resolution small-angle neutron scattering (USANS) measurements. The results for TiO₂ scattering and rheology show that shear induced dissociation occurs for certain dispersants and shear induced association of TiO₂ clusters is observed for other dispersants. The results suggest new ways to consider dispersant selection for paints and the quality of pigment dispersions.