Effect of Surfactant and Polymer Adsorption on the Viscosity of Aqueous Colloidal Silica Dispersions under Extreme Conditions

The effect of surfactant and polymeric additives on the viscosity behavior and stability of aqueous colloidal dispersions of silica particles under extreme conditions (low pH, high ionic strength) has been investigated. The surfactant and polymer used as dispersing agent were C12TAB, a cationic surfactant, and DarvanC, a commercially available polymer. It was found that the surfactant stabilized dispersions show a lower viscosity and a more uniform resistance to flow than the samples stabilized through electrostatic repulsion or polymer induced forces in the system. Stability analysis through turbidity measurements indicated that the state of the dispersion changes from an unstable regime to a stable regime above a critical concentration of C12TAB in the system. Viscosity measurements as a function of temperature indicates that C12TAB dispersing agent can further improve the flowability of the dispersion at higher temperatures.