General

Transient ζ-potential measurements in hydrophobic, TOPAS microfluidic substrates

  1. Vishal Tandon1,*,
  2. Sharath K. Bhagavatula2,
  3. Brian J. Kirby3

Article first published online: 27 JUL 2009

DOI: 10.1002/elps.200900028

Issue

ELECTROPHORESIS

ELECTROPHORESIS

Volume 30, Issue 15, pages 2656–2667, August 2009

Additional Information

How to Cite

Tandon, V., Bhagavatula, S. K. and Kirby, B. J. (2009), Transient ζ-potential measurements in hydrophobic, TOPAS microfluidic substrates. ELECTROPHORESIS, 30: 2656–2667. doi: 10.1002/elps.200900028

Author Information

  1. 1

    Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA

  2. 2

    School of Electrical and Computer Engineering, Cornell University, Ithaca, NY, USA

  3. 3

    Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA

*Cornell University – Sibley School of Mechanical and Aerospace Engineering, 238 Upson Hall, Ithaca, NY 14853, USA Fax: +1-607-255-1222

Publication History

  1. Issue published online: 7 AUG 2009
  2. Article first published online: 27 JUL 2009
  3. Manuscript Accepted: 29 MAR 2009
  4. Manuscript Revised: 18 MAR 2009
  5. Manuscript Received: 14 JAN 2009

Funded by

  • Sandia National Labs (DOE PECASE) and ACS-PRF

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Keywords:

  • Electrokinetic;
  • Electroosmosis;
  • Hydrophobic;
  • Transient;
  • ζ-potential

Abstract

We utilize time-resolved electrokinetic measurements in order to study the electrokinetic properties of silica and TOPAS microfluidic channels as a function of the time history of the fluid–solid interface. In pressure-driven flow through TOPAS microchannels, the ζ-potential as inferred from streaming potential measurements decays exponentially by a factor of 1.5 with a characteristic decay time of 3 h after the initial formation of the fluid–solid interface. A similar exponential decay is observed immediately after water is exchanged for ethanol as the solvent in the system. In electroosmotically driven flow through TOPAS microchannels, the ζ-potential as inferred through current monitoring experiments was constant in time. No electrokinetic transients were observed in silica microchannels under these flow conditions.

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