Ellipsoidal Janus Nanoparticles Simulated At Water/Oil Interfaces

Emulsions stabilized by nanoparticles, AKA Pickering emulsions, are finding many applications, including food processing and biofuel upgrading. Although spherical particles are often used for basic research, particles of different shapes are being produced and used, sometimes showing marked differences compared to results obtained when spherical particles are employed. We focus here on the behavior of ellipsoidal Janus nanoparticles. We employ dissipative particle dynamics simulations to uncover possible differences between the behaviors of these nanoparticles compared to that of spherical particles with similar characteristics. We report on the orientation of the nanoparticles with respect to the oil-water interface, the structure of the nanoparticles at the interface as a function of the surface coverage, with particular attention to the isotropic-to-nematic phase transition, and on the interfacial tension reduction caused by some of the nanoparticles considered. Implications of such observations on the interpretation of some experimental observations available in the literature will be discussed.