Study of polyelectrolyte capsule electrophoresis

TL;DR

This study analytically and numerically examines the electrophoretic motion of polyelectrolyte capsules with porous shells, revealing how permeability and material conductivity influence velocity and mobility, with implications for practical applications.

Contribution

It provides an analytical solution for capsule electrophoresis with porous shells and explores how permeability and conductivity affect velocity and mobility.

Findings

Velocity depends non-monotonically on permeability.

Decreasing shell conductivity reduces mobility.

Dielectric capsules can outperform conducting ones in electrophoresis.

Abstract

This paper investigates the problem of electrophoretic motion of a polyelectrolyte capsule with a porous arbitrary charged conducting shell in an electrolyte under the action of an external electric field. The corresponding boundary value problem for the velocity components and pressure in the case of small electrical potentials is analytically solved in quadratures. The solution is analyzed numerically for different values of the specific permeability of the capsule, and the thickness of the porous and the electric double layers. The minimum of electrophoretic velocity dependence on the inverse permeability of the porous layer has been found. This means that the capsule can move with the same velocity at different permeabilities of the porous shell, other conditions being equal, which is relevant for the practical use of the discovered effect. It is shown that the electrophoretic mobility decreases upon decrease in the conductivity of the material of constituting the porous layer. This means that a dielectric capsule can be used for electrophoresis as well. Moreover, its velocity will be even greater than that of a conducting capsule, all other conditions being equal.