Dynamics of non-coalescence in multi-drops suspended in insulating medium under electric field

An intriguing experimental observation in electrocoalescence of emulsions is the very low critical electric field (Ca) beyond which chaining and shorting is observed unlike the experimental and theoretical predictions in the case of two water droplets in oil. A numerical, analytical and experimental study on interaction between multiple conducting drops in a dielectric medium under an electric field is presented here. Non-coalescence of two conducting drops in a dielectric medium has been studied before. However, the presence of a third drop drastically changes the physics of approach, contact and further coalescence or non-coalescence. The interacting drops are bridged using an analytical model and numerically solved for asymmetrical double cones coming in contact. Thereafter their evolution under electric field is studied to observe the non-coalescence phenomenon. Findings suggest that a smaller drop between two bigger droplets hinder coalescence, effectively changing the critical Ca, and affecting the impact of drop sizes. Phase diagrams showing regimes of coalescence and non-coalescence are plotted as a function of the said parameters. These results suggest that theoretical studies should be able to predict the very low critical Ca observed in electrocoalescence of emulsions