Electro-osmotic counter pressure

Finally, the electro-osmotic (counter-) pressure, A is the pressure on the fluid required to create a Poiseuille flow (see (1.6.4.171) Just counterbalancing the electro-osmotic one. For a capillary with A = (a is the radius) and length ... 

CoEH r and Raydt compared the electro-osmotic velocity of different liquids through a glass capillary and found a very regular dependence of the electro-osmotic counter pressure on the dielectric constants of the liquid and the material of the wall. 

Figure 6.8 Fdectrokinetic phenomena (a) electro-osmotic flow of the medium caused by the flow of counter-ions under the influence of an electric field, (b) streaming potential set up when the liquid flows under the influence of a pressure gradient and carries counter-ions with it.

Another method of determination of the electro-osmosis consists in the measurement of the counter pressure generated by the electro-osmotic displacement of the liquid Th counter pressure causes the liquid to flow back through the capillary or plug In the stationary state the electro-osmotic flow is just counterbalanced by the backflow. 

---