in the deep primary minimum with the particle surfaces in The aggregation of four polystyrene latexes with similar surface intimate contact, and flocculation in the secondary minimum, charge and different diameter has been examined by small angle when a liquid film is retained between the particles so the light scattering. The DLVO model including aggregation at the energy well is shallower. secondary minimum qualitatively agrees with the experimental In Fig. 1, the energy difference, D Å V max 0 V min , is called dependence of colloidal stability on particle size. Repeptization the potential barrier and represents the energy opposing coexperiments, where the flocs were redispersed by washing away agulation. If particles approach each other with sufficient the coagulating salt, were carried out using two different methods: kinetic energies to overcome D, coagulation will occur and dialysis-turbidity and dilution-photon correlation spectroscopy.
the suspension will be destabilized. Flocculation takes place It was found that for the larger latexes the aggregates fragment after dilution, while for the smaller latexes the aggregates do not when particles remain at a distance corresponding to the fragment. These results correlate closely with the hypothesis that secondary minimum because they fail to overcome the enparticles may be captured within the secondary minimum of the ergy difference 0V min .
theoretical interaction energy curves.