Transient dynamic electrophoresis of a soft particle.

We introduce a general theory that explains the transient dynamic electrophoresis of a soft particle in an electrolyte solution when an oscillating electric field is suddenly applied. A simple approximate analytic expression is derived for the transient dynamic electrophoretic mobility of a soft particle that can be applied to practical situations. It is found that the mobility shows a damped oscillation, approaching its final value, similar to the behavior of a hard particle.