Ion Concentration Polarization in a Single and Open microchannel using Surface-patterned Nafion: Experimental and Theoretical Study

Abstract

We describe a novel and simple mechanism for inducing ion concentration polarization (ICP) using a surface-patterned perm-selective nanoporous film like Nafion in single, open microchannels. In this work, we not only develop a model to perform numerical simulations but also confirm the numerical simulation results with experimental results to verify the ICP phenomenon. That is. we characterize transport phenomena and distributions of ion concentration under various electric fields near the nafion film and show that single-channel based ICP (SC-ICP) is affected by nafion film thicknesses, strengths of applied electric fields, and ionic strengths of buffer solutions. We also emphasize that SC-ICP devices have several advantages over previous dual-channel ICP (DC-ICP) devices: inherently leak-tight, simple experimental setup requiring only one pair of electrodes, and low electrical resistances helping to avoid Joule heating, significant water dissociation, and membrane perm-selectivity breakdown but allowing high bulk flow. Lastly, we demonstrate that SC-ICP devices have high potential in massively parallel microchannels that require only one pair of electrodes and have higher possibilities of being easily integrated with traditional micro fluidic systems for bio technological applications.