A multilayer micro-electrochemical impedance spectroscopic (μ-EIS) system with an integrated Ag/AgCl reference electrode has been developed using MEMS technologies. This μ-EIS system is used to characterize ionic and fluidic transport across nanocapillary array membranes (NCAM), which are comprised of arrays of individual nanopores. Impedance measurements giving magnitude, phase, and I-V characteristics provide insight into the interaction between translocating ions and the electric double layer (EDL) within nanocapillaries due to changes in the surface zeta potential and the ionic charge of the electrolyte. U-EIS measurements for ionic flow through the NCAM with pore diameters from 10 to 800 nm with an aqueous salt solution indicate that these NCAM behave as nearly ideal RC circuits at electrolyte concentrations on the order of 100 mM, when the EDL within these pores do not overlap. Nyquist plots show an increase in the RC time constant with decreasing salt concentration. Under conditions of EDL overlap, hindered transport in the pores causes deviation from ideal RC circuit-like behaviour with the capacitive component of impedance beginning to dominate.
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