Fabrication and characterization of electroosmotic micropumps

Zeng, Shulin; Chen, Chuan‐Hua; Mikkelsen, J. C.; Santiago, Juan G.

doi:10.1016/s0925-4005(01)00855-3

Cited by 382 publications

(330 citation statements)

References 29 publications

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“…This results in an uncorrected (α = 1) eo = (1.8 ± 0.1) 10 − 10 m 2 V −1 s −1 for 1 mM NaCl at pH = 5.7 ± 0.1. The Debye length for 1 mM NaCl is approximately 9.6 nm, resulting in a correction factor α = 0.9 (Ai et al 2010;Zeng et al 2001), and a corrected eo = (2.0 ± 0.1) 10 −10 m 2 V −1 s −1 . The zeta potential ζ, estimated from this electroosmotic mobility is as follows:…”

Section: Resultsmentioning

confidence: 99%

“…The results from the limiting hydrodynamic pressure measurement can also be used to calculate µ eo , see (Zeng et al 2001): where Δp lim is the limiting hydrodynamic pressure and r the pore radius (0.2 µm), resulting in ζ = −1.9 ± 0.1 mV (corrected with α = 0.9), which is much smaller in magnitude than reported by others, e.g., −25 mV at pH = 6, for both pure polycarbonate and PVP-treated polycarbonate membranes (Kirby and Hasselbrink 2004;Lettmann et al 1999). Note that both ζ and eo should be calculated with the actual potential drop across the membrane, which we estimate to be about 75% of the actual applied potential, meaning that we have underestimated each by ~ 33%.…”

Section: Resultsmentioning

confidence: 99%

“…The net charge in this ionic layer depends on the electrolyte and the chemistry of the surface, and directly affects the velocity of flow generated per unit of electric field (the electroosmotic mobility). These pumps are most commonly associated with analytic chemistry and microfluidics, since they are compact, easily integrated into small devices, and can be implemented in a wide range of applications for micro-high-pressure liquid chromatography (µHPLC), capillary electrophoresis, chip-based assays, drug delivery, and device actuation (Chen et al 2004;Glawdel and Ren 2009;Li and Harrison 1997;Litster et al 2010;Manz et al 1994;Wang et al 2009;Zeng et al 2001). …”

Section: Introductionmentioning

confidence: 99%

“…Traditionally, most EOPs have been constructed with beds of packed silica particles (Zeng et al 2001) or relatively rigid porous materials such as anodic aluminum oxide (Ai et al 2010;Miao et al 2007). Polymeric, porous membranes function well as this media in flexible low-voltage EOPs since they are relatively thin, mechanically flexible, and can be highly porous.…”

Section: Introductionmentioning

confidence: 99%

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A large-area, all-plastic, flexible electroosmotic pump

Bengtsson

Robinson

2017

Microfluid Nanofluid

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A large-area, fabric-like pump would potentially have applications, for example, in controlling water transport through a garment, such as a rain jacket, regardless of the external temperature and humidity. This paper presents an all-plastic, flexible electroosmotic pump, constructed from commercially available materials: A polycarbonate membrane combined with the electrochemically active polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate that actively transports water using an electric potential that can be supplied by a small battery. By using electrochemically active polymer electrodes instead of metal electrodes, the electrochemical reaction that drives flow avoids the oxygen and hydrogen gas production or pH changes associated with water electrolysis. We observe a water mass flux up to 23 mg min −1 per cm 2 polycarbonate membrane (porosity 10-15%), at an applied potential of 5 V, and a limiting operating pressure of 0.3 kPa V −1 , similar to previously reported membrane-based electroosmotic pumps.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A large-area, all-plastic, flexible electroosmotic pump

Bengtsson

Robinson

2017

Microfluid Nanofluid

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“…The majority of anions are the hydroxide ions, as our working fluid is the de-ionized water. Storage and handling of DI water often results in a slight decrease in the pH value and a slight increase in bulk conductivity [10]. This could be due to the presence of atmospheric carbon dioxide.…”

Section: B Experimental Setup and Measurementsmentioning

confidence: 99%

Maximum efficiency of the electro-osmotic pump

Miao

Wang

et al. 2011

Phys. Rev. E

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Electro-osmotic effect in a porous medium arises from the electrically charged double layer at the fluid-solid interface, whereby an externally applied electric field can give rise to fluid flow. The electro-osmotic pump (EOP) is potentially useful for a variety of engineering and biorelated applications, but its generally low efficiency is a negative factor in this regard. A study to determine the optimal efficiency of the EOP and the condition(s) under which it can be realized is therefore of scientific interest and practical importance. We present the results of a theoretical and experimental study on the maximum efficiency optimization of the electrokinetic effect in artificially fabricated porous media with controlled pore diameters. It is shown that whereas the EOP efficiency increases with decreasing channel diameter, from 4.5 to 2.5 μm for samples fabricated on oxidized silicon wafers as expected for the interfacial nature of the electro-osmotic effect, the opposite trend was observed for samples with much smaller channel diameters fabricated on anodized aluminum oxide films, with the pore surface coated with silica. These results are in agreement with the theoretical prediction, based on the competition between interfacial area and the no-slip flow boundary condition, that an optimal efficiency of ∼1% is attained at a microchannel diameter that is five times the Debye length, with a zeta potential of ∼100 mV.

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Electroosmotic pumping in microchips with nonhomogeneous distribution of electrolytes

Chien

Bousse²

2002

Electrophoresis

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A general equation to calculate the node pressure at a junction in a microfluidic network is presented. The node pressure is generated from both the hydrodynamic flow due to the external applied hydraulic pressures and the electrokinetic flow resulted from the applied electric field. Pure electroosmotic flow has a plug-flow profile and pressure flow has a parabolic flow profile. In a first order approximation, these two flows can be treated separately, and the total flow is the sum of the two. An externally applied pressure simply creates a constant offset in the node pressure as long as the flow resistances remain the same. In a nonhomogeneous microfluidic network, where the electrical resistivity or the electroosmotic mobility is not constant everywhere, the differences in electroosmotic flow in various sections of the network will create an electroosmotically induced pressure at the internal nodes. Our theoretical approach can easily be extended to networks with more than one internal node. One prediction of this theory is that any variation in electroosmotic mobility or solution resistivity in different network branches will generate a pressure, and can thus be used as a pump. As an example, we demonstrate electroosmotic pumping in a high-low buffer system.

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Fabrication and characterization of electroosmotic micropumps

Cited by 382 publications

References 29 publications

A large-area, all-plastic, flexible electroosmotic pump

A large-area, all-plastic, flexible electroosmotic pump

Maximum efficiency of the electro-osmotic pump

Electroosmotic pumping in microchips with nonhomogeneous distribution of electrolytes

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