Conditions of Coagulation and Flocculation in Dilute Mini-emulsions

The peculiarities of droplet interaction and the possibility of their aggregation and disaggregation are analyzed for a dilute emulsion when the interaction between two droplets is not affected by the influence of other droplets. On the basis of Muller's model of doublet fragmentation, the characteristic time of this process (fragmentation time τd) is calculated in a wide range of electrolyte concentrations, surface potentials, and particle radii. A comparison of fragmentation time τd with the Smoluchowski time τsm of aggregation allows the domains for irreversible aggregation (coagulation) and reversible aggregation (flocculation) to be defined. Information about the domains of coagulation and flocculation are useful for selecting experimental conditions for the characterization of mini-emulsions at singlet–doublet equilibrium.