Redistribution of mobile surface charges of an oil droplet in water in applied electric field
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Date
2016-10
Authors
Li, Dongqing
Li, Mengqi
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Most researches on oil droplets immersed in aqueous solutions assume that the surface charges of oil droplets are, similar to that of solid particles, immobile and distributed uniformly under external electric field. However, the surface charges at the liquid–liquid interface are mobile and will redistribute under external electric field. This paper studies the redistribution of surface charges on an oil droplet under the influence of the external electrical field. Analytical expressions of the local zeta potential on the surface of an oil droplet after the charge redistribution in a uniform electrical field were derived. The effects of the initial zeta potential, droplet radius and strength of applied electric field on the surface charge redistribution were studied. In analogy to the mobile surface charges, the redistribution of Al2O3-passivated aluminum nanoparticles on the oil droplet surface was observed under applied electrical field. Experimental results showed that these nanoparticles moved and accumulated towards one side of the oil droplet under electric field. The redistribution of the nanoparticles is in qualitative agreement with the redistribution model of the mobile surface charges developed in this work.
Description
The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.cis.2016.08.006. © 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Keywords
Mobile surface charges, Liquid-fluid interface, Redistribution of surface charges, Local zeta potential, Electric field