FLOW MODULATION TECHNIQUE AND EHD IMPEDANCE - A TOOL FOR ELECTRODE PROCESSES AND HYDRODYNAMIC STUDIES

A review of flow modulation techniques is presented with a particular emphasis put on the EHD impedance. Due to the general formalism of impedances, a close relation is demonstrated between this EHD and the usual ac impedance. An analysis is hence presented about the general procedure for considering the effect of interfacial kinetics of finite rate. The technique is also demonstrated to be especially powerful when the interface is coated by a porous layer or is non-uniformly reactive (partial blocking). Finally, the concept of EHD impedance is also shown to be linked to the frequency response of microelectrodes used for investigating the properties of hydrodynamic fluctuations close to a wall. © 1990.