Local field and deformation of droplets in emulsions

Abstract

The deformation of individual liquid droplets in an applied electric or magnetic field is a traditional subject of research. Deformation processes in the system of droplets of the dispersed phase of an emulsion are of fundamental and applied interest but are currently poorly understood. Such processes must depend on the interaction of the droplets with each other. In this work, emulsions of ideal dielectric fluids in an electric field or ferrofluids in a magnetic field are considered. As a result of computer simulations and experimental studies, it is shown that the imposition of an external field on the system of droplets leads to their stretching along the field, accompanied by a slower process of formation of chain structures from droplets. At the initial stage of the system evolution, long-range interactions of polarized droplets can influence the degree of their deformation differently depending on the ratio of permeabilities of the dispersed phase and the dispersion medium. The subsequent formation of chain structures of droplets leads to the manifestation of short-range interactions of neighboring droplets in chains. These interactions, caused by the attraction of the droplets to each other, lead to the compression of the droplets in the field direction, which reduces the resulting degree of elongation of the droplets, regardless of the ratio of the properties of the droplets and the medium.