Dynamic superconcentration at critical-point double-layer gates of conducting nanoporous granules due to asymmetric tangential fluxes

Shau Chun Wang, Hsien-Hung Wei, Hsiao Ping Chen, Min Hsuan Tsai, Chun Ching Yu, Hsueh Chia Chang

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A transient 106-fold concentration of double-layer counterions by a high-intensity electric field is demonstrated at the exit pole of a millimeter-sized conducting nanoporous granule that permits ion permeation. The phenomenon is attributed to a unique counterion screening dynamics that transforms half of the surface field into a converging one toward the ejecting pole. The resulting surface conduction flux then funnels a large upstream electro-osmotic convective counterion flux into the injecting hemisphere toward the zero-dimensional gate of the ejecting hemisphere to produce the superconcentration. As the concentrated counterion is ejected into the electroneutral bulk electrolyte, it attracts co-ions and produce a corresponding concentration of the co-ions. This mechanism is also shown to trap and concentrate co-ion microcolloids of micron sizes too (macroions) and hence has potential application in bead-based molecular assays.

Original languageEnglish
Article number014102
Issue number1
Publication statusPublished - 2008 Jan 1


All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Materials Science(all)
  • Genetics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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