Microfluidics and Nanofluidics

, Volume 4, Issue 6, pp 471–487

Electrohydrodynamics around single ion-permselective glass beads fixed in a microfluidic device

  • Steffen Ehlert
  • Dzmitry Hlushkou
  • Ulrich Tallarek
Research Paper

DOI: 10.1007/s10404-007-0200-5

Cite this article as:
Ehlert, S., Hlushkou, D. & Tallarek, U. Microfluid Nanofluid (2008) 4: 471. doi:10.1007/s10404-007-0200-5

Abstract

This work demonstrates by direct visualization using confocal laser scanning microscopy that the application of electrical fields to a single-fixed, ion-permselective glass bead produces a remarkable complexity in both the coupled mass and charge transport through the bead and the coupled electrokinetics and hydrodynamics in the adjoining bulk electrolyte. The visualization approach enables the acquisition of a wealth of information, forming the basis for a detailed analysis of the underlying effects (e.g., ion-permselectivity, concentration polarization, nonequilibrium electroosmotic slip) and an understanding of electrohydrodynamic phenomena at charge-selective interfaces under more general conditions. The device used for fixing single beads in a microfluidic channel is flexible and allows to investigate the electrohydrodynamics in both transient and stationary regimes under the influence of bead shape, pore size and surface charge density, mobile phase composition, and applied volume forces. This insight is relevant for the design of microfluidic/nanofluidic interconnections and addresses the ionic conductance of discrete nanochannels, as well as nanoporous separation and preconcentration units contained as hybrid configurations, membranes, packed beds, or monoliths in lab-on-a-chip devices.

Keywords

Electrical double layerIon-permselectivityConcentration polarizationElectroosmotic flowNonlinear electroosmosisElectrohydrodynamicsMicrovortex

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Steffen Ehlert
    • 1
  • Dzmitry Hlushkou
    • 1
  • Ulrich Tallarek
    • 1
    • 2
  1. 1.Institut für VerfahrenstechnikOtto-von-Guericke-Universität MagdeburgMagdeburgGermany
  2. 2.Department of ChemistryPhilipps-Universität MarburgMarburgGermany