Confined polyelectrolyte solution driven by an external electric field

The transport properties of a dilute polyelectrolyte solution, confined inside a charged cylinder and driven by a constant external electric field, are studied using coarse-grained molecular dynamics simulations. The polyelectrolyte is negatively charged and modeled as linear bead-spring chains with explicit monovalent counterions and implicit solvent. We find that, when the confinement walls are negatively charged, the polyelectrolyte mobility is independent of the confinement charge density, whereas, when they are positively charged, the counterion mobility exhibits an intriguing non-monotonic dependence on the surface charge density. We study the dependence of the transport features on the diameter of the confinement, the presence of polarization effects, and on multivalent salts. We also study the mobility of the polyelectrolyte solution when the counterions of the charged surface are placed outside the confinement. In this case, the mobilities remain practically unaffected by the surface charge density, unless excluded volume effects become important.