Water soluble polymers prepared as water-in-oil (W/O) emulsions, commonly referred to as inverse emulsions, are employed to provide high molecular weight polymers in a low viscosity, high solids form. A critical application component is their efficiency to invert, i.e. transfer the polymer mass from within colloidal state dispersed in hydrocarbon medium to water. It is thus important to understand the fundamental changes taking place during the inversion process. The latter however is difficult to study due to the speed of the inversion process, the need to agitate the inverting system, and the lack of optical transparency.

Herein we offer a direct observation of a key step leading to the emulsion inversion that takes place upon dispersion of O/W emulsion into water continuum. Employing a novel experimental system, we provide direct evidence that inversion takes place through water diffusing through hydrocarbon media toward polymeric particles, swelling them and effectively rupturing polymer containing droplets into water continuum driven by osmotic pressure. Transfer phenomena analysis confirms the validity of the conclusions.