Nanoscale Electrokinetics and Microvortices: How Microhydrodynamics Affects Nanofluidic Ion Fluxстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 27 мая 2015 г.
Аннотация:When a direct current (DC) electric field is applied across an ion-selective nanoporous membrane or a nanochannel with an overlapping Debye layer, a surprising microvortex instability occurs on the side of the membrane/channel through which counterions enter. Despite its micro and nanolength scales, this instability exhibits all the hallmarks of other classical hydrodynamic instabilities - a subharmonic cascade, a wide-band fluctuation
spectrum, and a coherent structure dominated by spatiotemporal dynamics. Moreover, the resulting convection enhances the ion flux into the ion-selective medium and gives rise to an overlimiting-current bifurcation in the current-voltage relationship. This hydrodynamically driven nonequilibrium ion flux does not seem to have any equivalent in cell membrane ion channels. Yet, by introducing asymmetric entrances to provide different polarized regions and/or viscous arrest of the vortex instability, one can fabricate a hydrodynamic nanofluidic diode. With other modifications, hysteretic, excitable, and oscillatory ion flux dynamics could also be elicited - all with strong hydrodynamic features.