Approximate analytic expression for the pH-dependent electrophoretic mobility of soft particles

摘要

A theory on the electrophoretic mobility of a soft particle, i.e., a hard particle covered with an ion-penetrable surface layer of polyelectrolytes (Ohshima J Colloid Interface Sci 163: 474, 1994) is extended by taking into account the degree of dissociation of fixed ionizable groups in the polyelectrolyte surface layer. A simple approximate analytic expression for the pH-dependent electrophoretic mobility of a soft particle, carrying monovalent acidic ionizable groups in the polyelectrolyte layer, is derived, which involves the pH-dependent Donnan and surface potentials of a soft particle. With the help of the obtained expression for the pH-dependent electrophoretic mobility of soft particles, the electrophoretic fingerprinting approach can be applied to soft particles.