On the ac Measurements of the Electrical Conductivity of Dilute Colloidal Electrolytes

The details of ac-conductivity measurements in a colloidal electrolyte cell with flat control gate electrodes are discussed. The use of impedance diagnostics in studies of transport phenomena in such systems requires caution in the definition of the thickness of the screening accumulation layers that appear along the metal-electrolyte interfaces. The value of this characteristic length lambda 0 critically depends on the volume fraction phi circle dot of colloidal particles in the bulk of the electrolyte. Accounting for the dependence lambda 0(phi circle dot) makes it possible to consistently explain the large discrepancy in the available experimental data regarding the influence of the colloidal fraction on the effective conductivity of the colloidal suspension.