DOI: 10.1063/1.3120273. Experimental verification of Faradaic charging in ac electrokinetics

Experimental verification of Faradaic charging in ac electrokinetics

10.1063/1.3120273

Crossref journal-article

AIP Publishing

Biomicrofluidics (317)

Abstract

This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the production of ions through Faradaic hydrolytic reactions originating from direct application of voltage to electrolytic solutions during ac electrokinetics. Experiments were performed with symmetrical planar electrodes aligned along a microfluidic channel. Fluorescein, a pH-dependent dye, was employed as the pH indicator for the detection of ion production. Images were captured for analysis at various voltage levels. From analyzing the fluorescence intensity and its distribution, it can be concluded that the production of ions from hydrolytic reactions takes place and increases with the ac voltage. The coefficient of deviation indicates a significant enhancement at ac voltage above 11 Vpp. Lastly, we demonstrate a strategy using dc-biased ac electrokinetics to achieve controllability in direction and magnitude of the net fluid flow in pumping application.

Bibliography

Ng, W. Y., Lam, Y. C., & RodrÃguez, I. (2009). Experimental verification of Faradaic charging in ac electrokinetics. Biomicrofluidics, 3(2).

Authors 3

Wee Yang Ng (first)
Yee Cheong Lam (additional)
Isabel Rodríguez (additional)

References 28 Referenced 24

10.1139/v05-255 / Can. J. Chem. Eng. (2006)
10.1063/1.3056045 / Biomicrofluidics (2009)
10.1007/s10404-004-0024-5 / Microfluid. Nanofluid. (2005)
10.1063/1.3037326 / Biomicrofluidics (2008)
10.1063/1.2973661 / Biomicrofluidics (2008)
10.1021/ac070810u / Anal. Chem. (2007)
10.1103/PhysRevE.63.016305 / Phys. Rev. E (2000)
10.1016/S0925-4005(03)00289-2 / Sens. Actuators B (2003)
10.1039/b314123c / Lab Chip (2004)
10.1063/1.2832624 / J. Appl. Phys. (2008)
10.1063/1.1767286 / J. Appl. Phys. (2004)
10.1039/b408382m / Analyst (Lond.) (2004)
10.1063/1.1873034 / J. Appl. Phys. (2005)
10.1063/1.2358823 / Appl. Phys. Lett. (2006)
10.1021/la800423k / Langmuir (2008)
10.1063/1.2908026 / Biomicrofluidics (2008)
10.1039/b515852d / Lab Chip (2006)
10.1039/b813639d / Lab Chip (2009)
{'year': '2009', 'key': '2023062417044453700_c19'} (2009)
10.1088/0022-3727/31/18/021 / J. Phys. D (1998)
10.1103/PhysRevE.61.R45 / Phys. Rev. E (2000)
10.1103/PhysRevE.73.056313 / Phys. Rev. E (2006)
10.1016/j.jcis.2007.01.076 / J. Colloid Interface Sci. (2007)
{'key': '2023062417044453700_c24', 'first-page': '8', 'volume-title': 'CRC Handbook of Chemistry and Physics', 'year': '2008', 'edition': '88th ed.'} / CRC Handbook of Chemistry and Physics (2008)
10.1021/ac00101a006 / Anal. Chem. (1995)
10.1021/ar010110q / Acc. Chem. Res. (2002)
10.1021/la970568u / Langmuir (1997)
10.1021/ac0353942 / Anal. Chem. (2004)

Dates

Type	When
Created	16 years, 4 months ago (April 23, 2009, 6:34 p.m.)
Deposited	2 years, 2 months ago (June 24, 2023, 10:49 p.m.)
Indexed	5 days, 21 hours ago (Aug. 23, 2025, 1:04 a.m.)
Issued	16 years, 4 months ago (April 23, 2009)
Published	16 years, 4 months ago (April 23, 2009)
Published Online	16 years, 4 months ago (April 23, 2009)
Published Print	16 years, 2 months ago (June 1, 2009)

Funders 0

None

BibTeX

@article{Ng_2009, title={Experimental verification of Faradaic charging in ac electrokinetics}, volume={3}, ISSN={1932-1058}, url={http://dx.doi.org/10.1063/1.3120273}, DOI={10.1063/1.3120273}, number={2}, journal={Biomicrofluidics}, publisher={AIP Publishing}, author={Ng, Wee Yang and Lam, Yee Cheong and Rodríguez, Isabel}, year={2009}, month=apr }

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