Flocculation of dispersed phase droplets in water-in-oil emulsions: Experiment and mathematical simulation

Abstract

The sedimentation stability of water-in-oil (W/O) emulsions is shown to drastically rise at dispersed phase fractions of higher than 0.25–0.30. According to electron microscopy data, in W/O emulsions, dispersed phase droplets can form both globular flocs and network structures, with the latter prevailing in sedimentation-stable emulsions. The fractal dimensions are determined for different types of flocs. The aggregation of dispersed phase droplets is mathematically simulated according to the models of the diffusion-limited cluster aggregation and Brownian dynamics. Both models are shown to predict the formation of aggregates with structures similar to flocs observed in micrographs. The value of the percolation threshold calculated for aggregates within the framework of the Brownian dynamics model coincides with the fraction of the dispersed phase in W/O emulsions at which the network structures begin to be formed.