Influence of external electric field on the polarity of water droplets in water-in-oil emulsion phase transition

The effect of external electric field on the interactions among water droplets in water-in-oil emulsion is quantified in this work. The obtained contribution is introduced into the potential energy function among the drops. Using the first order Barker–Henderson perturbation theory, a modified thermodynamic model has been developed in order to find equilibrium conditions at various temperatures and external electric fields. The results show that the modification on the dipole–dipole interactions has pronounced effects on the calculated equilibrium conditions, especially on the predicted required electric field for breaking the emulsion. Phase diagrams for different drop diameters and adsorption layer thicknesses are plotted and the final results are discussed compared to the experimental data available in the literature.

Figure optionsDownload as PowerPoint slideResearch highlights▶ The main objective of this research is to present a thermodynamic model capable of predicting the electrical field strength required for the phase transition of water droplets in water-in-oil emulsion. ▶ The derived thermodynamic model is based on perturbation theory and consists of a repulsive steep term, an attraction van der Waals contribution and a dipole–dipole attraction term between the drops. The effect of the induced dipole on water droplets, due to the presence of an external electric field, is considered and modeled. The predicted phase diagrams for different values of the diameter of the droplets and the adsorption layer thicknesses are consistent with the available experimental data.