Coupling between electroosmotically driven flow and bipolar faradaic depolarization processes in electron-conducting microchannels

Qian, Shizhi; Duval, Jérôme F. L.

doi:10.1016/j.jcis.2005.09.069

Cited by 15 publications

(30 citation statements)

References 31 publications

(68 reference statements)

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“…As in previous work [33], we consider a metallic and cylindrical microchannel of radius b and length L as depicted in Fig. 1.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

“…Recently, we described the basis for a novel type of manipulation of electroosmotic flows in electron-conducting channels or in channels coated with metallic patches [33]. Contrary to the cases reported in [23][24][25][26][27] and previously commented on, the method does not suffer from the need to apply an external electric field perpendicular to the interface or the requirement of a redox active polymer film at the surface.…”

Section: Introductionmentioning

confidence: 99%

“…Beyond a threshold value of the lateral electric field applied in the electrolyte solution, which induces electroosmosis, oxidation and reduction reactions occur concomitantly at the two extremities of the substrate. This results in a nonuniform distribution of the electric field in solution [33]. The corresponding spatial-dependent potential drop across the interface alters the local double layer composition along the channel wall and in particular the electrokinetic potential.…”

Section: Introductionmentioning

confidence: 99%

“…The corresponding spatial-dependent potential drop across the interface alters the local double layer composition along the channel wall and in particular the electrokinetic potential. The conjugated impacts of those electrochemical and chemical-mediated processes on the electroosmotic flow patterns were illustrated in [33], where the case of irreversiblethat is kinetically limited-electron transfer (e.t.) reactions was explicitly considered.…”

Section: Introductionmentioning

confidence: 99%

“…(1)) along the channel. Since these two quantities are strongly depending on the extent of faradaic depolarization of the interface [33], it is timely to compute and discuss the electroosmotic flow patterns as a function of the kinetic rate constant of the bipolar e.t. reactions along the microchannel.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Modulation of electroosmotic flows in electron-conducting microchannels by coupled quasi-reversible faradaic and adsorption-mediated depolarization

Qian

Duval²

2006

Journal of Colloid and Interface Science

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“…As in previous work [33], we consider a metallic and cylindrical microchannel of radius b and length L as depicted in Fig. 1.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modulation of electroosmotic flows in electron-conducting microchannels by coupled quasi-reversible faradaic and adsorption-mediated depolarization

Qian

Duval²

2006

Journal of Colloid and Interface Science

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Manipulating particles in microfluidics by floating electrodes

et al. 2010

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Various particle manipulations including enrichment, movement, trapping, separation, and focusing by floating electrodes attached to the bottom wall of a straight microchannel under an imposed DC electric field have been experimentally demonstrated. In contrast to a dielectric microchannel possessing a nearly uniform surface charge (or ζ potential), the metal strip (floating electrode) is polarized under the imposed electric field, resulting in a nonuniform distribution of the induced surface charge with a zero net surface charge along the floating electrode's surface, and accordingly induced-charge electroosmotic flow near the metal strip. The induced induced-charge electroosmotic flow can be regulated by controlling the strength of the imposed electric field and affects both the hydrodynamic field and the particle's motion. By using a single floating electrode, charged particles could be locally concentrated in a section of the channel or in an end-reservoir and move toward either the anode or the cathode by controlling the strength of the imposed electric field. By using double floating electrodes, negatively charged particles could be concentrated between the floating electrodes, subsequently squeezed to a stream flowing in the center region of the microchannel toward the cathodic reservoir, which can be used to focus particles.

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Microchannel plate as a novel bipolar electrode for high‐performance enrichment of anions

Cao

Yobaş

2013

Electrophoresis

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Microchannel plate (MCP), a high-porosity glass membrane used as an electron multiplier in analytical/scientific instruments for the detection of energetic photons and charged particles is demonstrated here as a highly effective bipolar electrode (BPE) for electrokinetic focusing of anions. Assembled between a pair of microfluidic channels filled with an electrolyte buffer and subjected to a sufficient bias potential, MCP supports faradaic reactions, owing to its semiconducting characteristics. Thousands of microcapillary tubes fused together define MCP and act in unison such that each microcapillary serves as a tiny BPE surrounding an infinitesimal element of bulk electrolyte with a large surface-area-to-volume ratio and hence performs highly effective as compared to a planar electrode inlaid into a microchannel. This performance has been validated here where concentration enrichment of a fluorescent tracer has been demonstrated at a remarkable rate of up to 175-fold/s exceeding those reported for planar BPEs. We attribute such high performance to the rapid onset of ion-depletion zone and subsequent steep field gradient, signifying the high-porosity structure of MCP as an effective BPE.

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Coupling between electroosmotically driven flow and bipolar faradaic depolarization processes in electron-conducting microchannels

Cited by 15 publications

References 31 publications

Modulation of electroosmotic flows in electron-conducting microchannels by coupled quasi-reversible faradaic and adsorption-mediated depolarization

Modulation of electroosmotic flows in electron-conducting microchannels by coupled quasi-reversible faradaic and adsorption-mediated depolarization

Manipulating particles in microfluidics by floating electrodes

Microchannel plate as a novel bipolar electrode for high‐performance enrichment of anions

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