Interfacial Phenomena and Droplet Size of Particle Stabilized Emulsions in Oscillatory Shear.

Production of particle stabilized oil in water emulsions has been investigated both theoretically and experimentally under oscillatory shear conditions using different stabilizing particles (SPs). The investigation included analysis of the interaction between particles interfacial stability and droplets breakage and coalescence. For hydrophobic SPs, droplets maintained their sizes as determined by torque balance (TB) without significant breakage or coalescence. For the more hydrophilic SPs, larger droplets formed that broke by eddies in the inertial subrange. At higher fluid shear stresses, loss of the SPs occurred during droplet formation leading to near bare droplet surface and coalescence to much larger sizes with subsequent fragmentation by capillary instabilities. The final droplet size in both cases was very different from TB model predictions. A modeling approach is proposed that combined both TB and droplet breakage and coalescence mechanisms. Comparison between the experimental results and the models predictions showed satisfactory agreement. [ABSTRACT FROM AUTHOR]