Enhancement of Overlimiting Current in a Three-Dimensional Hierarchical Micro/Nanofluidic System by Non-uniform Compartmentalization

Abstract Overlimiting current (OLC) is a non-linear current response that occurs related to an ion concentration polarization (ICP) phenomenon in micro/nanofluidic systems and holds great importance since it represents the rate of selective ion transportation through perm-selective structure. For last two decades, numerous studies of OLC have been reported about understanding the fundamentals of nanoelectrokinetics and enhancing ion transportation through perm-selective membranes. Recent study reported that the alignment of non-uniform microspace near the perm-selective membranes in two-dimensional micro/nanofluidic systems can significantly enhance OLC, i.e., overlimiting conductance (σOLC). This is attributed to recirculation flow induced by combination of unbalanced electroosmosis and induced pressure driven flow among non-uniform microspaces. However, 2D micro/nanofluidic systems hav…