The impact of the ionic concentration on electrocoalescence of the nanodroplet driven by dielectrophoresis

The impact of the ionic concentration on the coalescence of the nanodroplet driven by dielectrophoresis is investigated through the MD method. The microscopic mechanism on the enhanced electrocoalescence is that the ions form asymmetric distributions similar to the electrical double layer in a non-uniform electric field. The ions in the adsorption layer drag the other ions in the diffusion layer to migrate, which is beneficial for improving the electrocoalescence. For the low ionic concentration droplets, the increases in the ionic concentration enhance the asymmetry distribution of ions because of more ions overcome the interaction of partials and diffuses into the adsorption layer. For the high ionic concentration droplets, the interaction of particles is enhanced and restricts the formation of the electric double layer. The ions appear the symmetrical distributions gradually with the ionic concentration increasing. That results in the DEP force reducing. Moreover, increases in the intensity and the gradient of the electric field promote the efficiency of the electrocoalescence because the larger Coulomb force improves the probability of ion separating from the bulk ions, but the latter does not affect the distribution of ions inside the nanodroplet, and accelerates only the formation rate of the double electrode layers. (C) 2019 Elsevier B.V. All rights reserved.