Rheology of macro- and nano-emulsions in the presence of micellar depletion attraction

Abstract

In this work, we investigate the effect of interdroplet interaction on the rheological behavior of oil-in-water emulsions within a range of macro- to nano-droplet sizes and various volume fractions from dilute to concentrated regimes. We determine the total interdroplet interaction from electrostatic, van der Waals, and depletion attraction contributions. At constant surfactant concentration, the depth of attractive potential is much higher than kBT for submicron emulsions and macroemulsions, whereas it is on the order of thermal energy for nanoemulsions. Thus, as the droplet size decreases in systems with considerable yield stress below jamming transition, the emulsions undergo a gel-to-glass transition. The yield strain ranges of gel and glassy systems overlap, although the droplets in gels undergo the dissipative rearrangement before macroscopic translational motion.