Stability of macroemulsions

The rupture of the thin films separating emulsion droplets has long been considered to be triggered by the long-range, attractive van der Waals forces; however, this study conducted in a shearfield coalescer shows that systems containing surfactant may, in some cases, yield trends contrary to predictions based on this hypothesis. These trends can be understood in terms of a new mechanism leading to film rupture which is called here percolation-enhanced coalescence.Those regimes in which this new mechanism dominates can be determined based on simple equilibrium phase behavior studies of the surfactant, oil, and water mixtures using the percolation model proposed here.