Nanoscale Electrokinetics and Microvortices:: how Microhydrodynamics Affects Nanofluidic Ion Flux

• Hsueh-Chia Chang ^[1] ; Gilad Yossifon ^[2] ; Evgeny A. Demekhin ^[3]
  1. [1] University of Notre Dame

     University of Notre Dame

     Township of Portage, Estados Unidos

     
  2. [2] Technion – Israel Institute of Technology

     Technion – Israel Institute of Technology

     Israel

     
  3. [3] Kuban State University

     Kuban State University

     Rusia

     

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• Localización: Annual review of fluid mechanics, ISSN 0066-4189, Nº. 44, 2012, págs. 401-426
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • 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 nano length 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.