  Induced-charge electro-osmosis (ICEO) is shown to control the length scale of
the diffusion layer (DL), which in turn, affects the diffusion limited ion
transport through the microchannel-Nafion membrane system. The ICEO vortices
form at an interdigitated floating electrode array embedded within a
microchannel interfacing a Nafion membrane and stir the fluid, arresting the
diffusive growth of the depletion layer. By varying the spacing between the
array and the membrane we are able to control the length of the DL. Activating
the electrodes results in further enhancement of the fluid stirring due to the
emergence of alternating-current electro-osmotic (ACEO) flow on top of the
ICEO. Such a new method of controlling the DL with an electrode array is of
great importance in many CP related realizations.
