Electroosmotic flow and zone broadening in microfluidic channels of variable cross-section and wall charge

Sandip Ghosal*, Z. Lu

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Electroosmotic flow is often the method of choice for generating fluid flows in microfluidic devices. The resulting flow has a characteristic flat profile which has the advantage of very low axial dispersion. This is only the case, however, if the wall zeta potential is constant. In many applications, the wall zeta potential is variable, either through accident (wall adsorption of analytes) or design (patterned charges). An analytical solution is developed for electroosmotic and pressure driven flows in straight microfluidic channels of arbitrary cross-sectional shape and distribution of zeta-potential, in the asymptotic limit where variations in the axial direction take place on long length scales compared to a characteristic diameter. A method is provided for computing "effective fluidic impedances" for such inhomogeneous microfluidic channels. The theoretical results are used to explain certain experimental data on CZE in a straight microcapillary.

Original languageEnglish (US)
Title of host publication2002 International Conference on Modeling and Simulation of Microsystems - MSM 2002
EditorsM. Laudon, B. Romanowicz
Pages68-71
Number of pages4
StatePublished - Dec 1 2002
Event2002 International Conference on Modeling and Simulation of Microsystems - MSM 2002 - San Juan, Puerto Rico
Duration: Apr 21 2002Apr 25 2002

Other

Other2002 International Conference on Modeling and Simulation of Microsystems - MSM 2002
CountryPuerto Rico
CitySan Juan
Period4/21/024/25/02

Keywords

  • Dispersion
  • Electroosmosis
  • Electrophoresis
  • Zeta-potential
  • Zone-broadening

ASJC Scopus subject areas

  • Engineering(all)

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