Electrohydrodynamic behavior of polyelectrolyte vesicle accompanied with ions in solution through a narrow pore induced by electric field

Abstract

We use finite element numerical simulations to study the electrohydrodynamic behavior of a polyelectrolyte vesicle passing through a narrow pore in an electrically neutral system. We systematically explain the deformation and migration of the vesicle, including the motion of ions in the solution, the strain energy and stress distribution of the vesicle under electric drive, and the minimum potential difference (critical potential difference) that allows the vesicle to pass through the narrow pore. The migration of the vesicle into the pore drives ion motion, causing rapid changes in the ion flux and potential difference in the pore, which may provide an important means to determine whether the vesicle passes through the pore. In addition, the changes in ion concentration and potential difference in the pore will not disappear when the radius of the vesicle is smaller than the pore diameter. We also find that the critical potential difference is independent of the pore diameter, but it does depend strongly on the vesicle's radius. When the vesicle's radius becomes larger than the pore diameter, the critical potential difference increases by an order of magnitude, which provides an effective method for separation of vesicles.