Electrophoresis of diffuse soft particles with dielectric charged rigid core grafted with charge regulated inhomogeneous polymer segments

Abstract

Abstract In this study we consider the most general case of soft particle electrophoresis in which the inner core is considered to be dielectric and nonconducting with a fixed volumetric charge density coated with a diffuse polymer layer containing both acidic and basic functional groups. A semi-analytic approach under a weak-field assumption is adopted to study the electrophoresis theoretically. Our results are found to be in good agreement with the existing solutions for limiting cases. We have illustrated the effect of core charge density, electrolyte pH, ionic concentration and the degree of inhomogeneity of the polymer layer on the soft particle electrophoresis. The dependence of the critical value of pH for which the soft particle have zero mobility on the core charge density and degree of inhomogeneity of the diffuse layer is analyzed. A reversal in the mobility of a soft particle with oppositely charged core and soft layer can be achieved when the Debye length is lower than the thickness of the soft layer in which the electrophoresis is dominated by the electrostatic property of the polymer layer.