Approximate expression for the electrophoretic mobility of a spherical colloidal particle covered with an ion-penetrable uncharged polymer Layer

An approximate analytic expression is derived for the electrophoretic mobility of a charged spherical colloidal particle covered with an ion-penetrable uncharged polymer layer in an electrolyte solution by taking into account the relaxation effects. This expression is applicable for all values of zeta potentials at large κa(κa≥ca. 30), where κ is the Debye–Huckel parameter and a is the radius of the particle core. A simple expression for the ratio of the electrophoretic mobility of a polymer-coated particle to that of a bare particle without a polymer layer is also given.