Synthesizing Pickering Nanoemulsions via condensation on oils

In this work a novel method is presented to synthesize Pickering emulsions. Unlike the typical two-step techniques which are widely being used to make emulsions herein we propose a single process which leads to small size (Micro-Nano) water droplets dispersion in oil phase possessing hydrophobic silica nanoparticles . The predominant advantage stems from the heterogenous nucleation of water vapor nuclei on the sub-cooled oil-air interface associated with spontaneously submergence within the oil. The positive spreading coefficient of oil prevents droplet growth induced by vapor diffusion via cloaking, while irreversible particle adsorption suppresses the merging event occurring between the adjacent droplets. We discuss how particles properties such as hydrophobicity, size, concentration as well as condensation time affect the emulsion size. The competition between particle adsorption rate, condensation rate can be finely adjusted using above-mentioned parameters to obtain stable nano-emulsions at even low nanoparticle loadings. We discuss the energetics of emulsion formation by condensation, and show the vapor-condensation process can be easily scaled to produce larger quantities of emulsions in energy-efficient manner.