Temperature dependence of salt-induced aggregation in poly(ethylene oxide)-coated latex particle suspensions

The influence of temperature on the kinetics of aggregation of poly(ethylene oxide) coated latex particles induced by adding appropriate amount of simple electrolyte has been investigated by means of dynamic light scattering measurements. The hydrodynamic radius of the resulting aggregates markedly depends on the molecular weight of the polymer adsorbed on the polystyrene particle surface. We investigated the influence of poly(ethylene oxide) of three different molecular weights (from 8 to 5 × 103 kD) in the temperature interval from 10 to 50 °C. A bridging mechanism has been suggested as responsible, at an intermediate surface coverage, for enhancing the aggregation rate. The influence of the polymer solubility in this process is briefly discussed.