Rates of flocculation of latex particles by cationic polymers

Abstract Suspensions of 0.2 μm polystyrene particles have been flocculated with three cationic polymers differing only in molecular weight. Using a simple light scattering technique, relative rates of flocculation were obtained and optimum flocculant concentrations could be fairly dearly defined. Under given conditions the optimum concentration was independent of the molecular weight of the polymer. The rate of polymer flocculation was found to increase with decreasing ionic strength and the maximum rate observed was about twice that given by high concentrations of electrolyte or by acid. An explanation in terms of uneven charge distribution on the particles is proposed. There are indications that such studies could be extended to give information on rates of polymer adsorption and rearrangement on particle surfaces.