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

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

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
JournalBiomicrofluidics
Volume2
Issue number1
DOIs
Publication statusPublished - 2008

All Science Journal Classification (ASJC) codes

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

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