*2.1.2 Electroosmosis*

Electroosmosis, on the other hand, is associated with the movement of the liquid medium relative to a stationary charged surface. The walls of the capillary cell carry a surface charge which causes the liquid adjacent to the wall to flow, once the electric field is applied. This electroosmotic flow superimposes the colloidal particles' electrophoretic mobility [14]. In a closed system, this flow is countered by another reverse flow down the center of the capillary cell. Due to that, there exists a point, known as the stationary layer, in which the two flows cancel each other and result in a zero net electroosmotic flow [14]. At that point, the true electrophoretic velocity is measured [14]. The position of the stationary layer depends on the geometry of the cell.
