ELECTRODE EFFECTS IN DIELECTRIC-SPECTROSCOPY OF COLLOIDAL SUSPENSIONS

We present a simple model to account for electrode polarization in col loidal suspensions. Apart from correctly predicting the omega(-3/2) de pendence for the dielectric permittivity at low frequencies omega, the model provides an explicit dependence of the effect on electrode spac ing. The predictions are tested for the sodium bis(2-ethylhexyl) sulfo succinate (AOT) water-in-oil microemulsion with iso-octane as continuo us phase. In particular, the dependence of electrode polarization effe cts on electrode spacing has been measured and is found to be in accor dance with the model prediction. Methods to reduce or account for elec trode polarization are briefly discussed.