Influence of the fragmentation of multiple globules on the rheological properties of W/O/W multiple emulsions

The purpose of our work was to study the behavior of W/O/W multiple emulsions submitted to a shear flow by applying the theoretical framework developed by Taylor to describe the deformation and the bursting of simple oily globules under shear. The formulation parameters taken into consideration were the mass fraction of dispersed phase and the viscosity of the continuous phase. The conductometric analysis carried out to study the release under shear of the electrolyte entrapped inside the internal aqueous phase of the multiple emulsions, together with microscopic and granulometric analyses, showed that Taylor's framework could be applied to multiple emulsions. Rheological analyses were also carried out and confirmed the bursting of the globules in parallel with the granulometric studies. This phenomenon could be visualized by rheograms showing a more or less large hysteresis loop. The mechanisms which occur during the bursting are complex and depend on the shear time. (C) 2000 The Society of Rheology. [S0148-6055(00)00302-3].