Viscous Oil Emulsification by Catastrophic Phase Inversion: Influence of Oil Viscosity and Process Conditions

This study deals with the description of the influence of oil viscosity and process conditions on catastrophic phase inversion, through the analysis of the effects of formulation and process variables on the dispersed phase fraction at which the inversion is triggered. The in situ simultaneous follow-up of viscosity and conductivity measurements allowed, from a process point of view, to emphasize the effect of the aqueous phase addition rate on the catastrophic phase inversion point (PIP) and multiple w/O/W emulsion formation. Thus if the aqueous phase is added by very small fractions, formulation dominates and the inversion phenomenon can be accelerated, as a consequence of multiple emulsion formation, that greatly increases the volume of effective dispersed phase. An increase in oil viscosity greatly increased the tendency of the oily phase to become the dispersed phase and promoted the formation of highly concentrated emulsions (about 80 to 95% in volume) after inversion.