Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel

Masilamani, Kannan; Ganguly, Suvankar; Feichtinger, Christian; Bartuschat, Dominik; Rüde, Ulrich

doi:10.1088/0169-5983/47/3/035505

Cited by 24 publications

(18 citation statements)

References 34 publications

(46 reference statements)

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“…. In the fine‐to‐coarse direction of the surface roughness gradient (electropherograms A–C), the zone of thiourea was fronting (the EOF velocity decreased with an increase in roughness height before detection ) while in the coarse‐to‐fine direction (electropherograms Ai–Ci) it was tailing (the EOF velocity increased with an decrease in roughness height before detection ), similarly as it was described by the mathematical model for a microchannel . At the BGE pH higher than pH 7.0 local changes in pressure zone which make the central flow velocity smaller than that in the near‐wall region already does not affect the peak shape.…”

Section: Resultsmentioning

confidence: 73%

“…Local changes in pressure zone are induced that make the central flow velocity smaller than that in the near‐wall region, and significantly reduce the flow rate through the rough microchannel . The induced high‐pressure zone occurs at the front of the rough elements, whereas the low‐pressure zone is in the tail region to satisfy the flow continuity . Simultaneously, the EOF velocity decreases with an increase in roughness height and increases with an increase in roughness length .…”

Section: Introductionmentioning

confidence: 99%

“…Local changes in pressure zone are induced that make the central flow velocity smaller than that in the near-wall region, and significantly reduce the flow rate through the rough microchannel [2,3]. The induced high-pressure zone occurs at the front of the Correspondence: Marie Horká, Institute of Analytical Chemistry of the CAS, v. v. i., Veveří 97, 602 00 Brno, Czech Republic E-mail: horka@iach.cz Fax: (+420)- Abbreviations: EtOH, ethanol; FS, fused silica; GOTMS, (3-glycidyloxypropyl)trimethoxysilane; SCW, supercritical water rough elements, whereas the low-pressure zone is in the tail region to satisfy the flow continuity [3,5]. Simultaneously, the EOF velocity decreases with an increase in roughness height and increases with an increase in roughness length [3].…”

Section: Introductionmentioning

confidence: 99%

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Capillary electrophoresis in a fused-silica capillary with surface roughness gradient

et al. 2016

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The electro-osmotic flow, a significant factor in capillary electrophoretic separations, is very sensitive to small changes in structure and surface roughness of the inner surface of fused silica capillary. Besides a number of negative effects, the electro-osmotic flow can also have a positive effect on the separation. An example could be fused silica capillaries with homogenous surface roughness along their entire separation length as produced by etching with supercritical water. Different strains of methicillin-resistant and methicillin-susceptible Staphylococcus aureus were separated on that type of capillaries. In the present study, fused-silica capillaries with a gradient of surface roughness were prepared and their basic behavior was studied in capillary zone electrophoresis with UV-visible detection. First the influence of the electro-osmotic flow on the peak shape of a marker of electro-osmotic flow, thiourea, has been discussed. An antifungal agent, hydrophobic amphotericin B, and a protein marker, albumin, have been used as model analytes. A significant narrowing of the detected zones of the examined analytes was achieved in supercritical-water-treated capillaries as compared to the electrophoretic separation in smooth capillaries. Minimum detectable amounts of 5 ng/mL amphotericin B and 5 μg/mL albumin were reached with this method.

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Section: Resultsmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Capillary electrophoresis in a fused-silica capillary with surface roughness gradient

et al. 2016

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“…Stacked micelles and swept analytes migrate into the low-conductivity BGE [3]. Simultaneously, the induced high-pressure zone occurs at the front of the rough elements, whereas the low-pressure zone is in the tail region to satisfy the flow continuity [26,31]. The higher local changes in pressure zone which make the central flow velocity smaller than that in the near-wall region [19,26] does not affect the peak shape in terms of its tailing at BGE pH 7.0.…”

Section: Choice Of Bge Compositionmentioning

confidence: 99%

Fused silica capillaries with two segments of different internal diameters and inner surface roughnesses prepared by etching with supercritical water and used for volume coupling electrophoresis

et al. 2017

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In this work, single-piece fused silica capillaries with two different internal diameter segments featuring different inner surface roughness were prepared by new etching technology with supercritical water and used for volume coupling electrophoresis. The concept of separation and online pre-concentration of analytes in high conductivity matrix is based on the online large-volume sample pre-concentration by the combination of transient isotachophoretic stacking and sweeping of charged proteins in micellar electrokinetic chromatography using non-ionogenic surfactant. The modified surface roughness step helped to the significant narrowing of the zones of examined analytes. The sweeping and separating steps were accomplished simultaneously by the use of phosphate buffer (pH 7) containing ethanol, non-ionogenic surfactant Brij 35, and polyethylene glycol (PEG 10000) after sample injection. Sample solution of a large volume (maximum 3.7 μL) dissolved in physiological saline solution was injected into the wider end of capillary with inlet inner diameter from 150, 185 or 218 μm. The calibration plots were linear (R ∼ 0.9993) over a 0.060-1 μg/mL range for the proteins used, albumin and cytochrome c. The peak area RSDs from at least 20 independent measuremens were below 3.2%. This online pre-concentration technique produced a more than 196-fold increase in sensitivity, and it can be applied for detection of, e.g. the presence of albumin in urine (0.060 μg/mL).

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“…With the reduction of the characteristic scale of the study of fluid motion, a new flow effect was found. e coupling of the electric field force, the flow field, the temperature field and the ion motion within the microchannel, the electroosmotic flow, electrophoresis, induced electroosmotic flow, and other electrical phenomena can be used to achieve microfluidic (microparticle) transport and control [5,6]. Electrokinetic phenomena in microfluidics are caused by the interaction between the applied electric field and the diffusion layer in the electric double layer.…”

Section: Introductionmentioning

confidence: 99%

Design and Numerical Study of Micropump Based on Induced Electroosmotic Flow

Zhang

Jiang

Gao

et al. 2018

Journal of Nanotechnology

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Induced charge electroosmotic flow is a new electric driving mode. Based on the Navier-Stokes equations and the PoissonNernst-Planck (PNP) ion transport equations, the finite volume method is adopted to calculate the equations and boundary conditions of the induced charge electroosmotic flow. In this paper, the formula of the induced zeta potential of the polarized solid surface is proposed, and a UDF program suitable for the simulation of the induced charge electroosmotic is prepared according to this theory. At the same time, on the basis of this theory, a cross micropump driven by induced charge electroosmotic flow is designed, and the voltage, electric potential, charge density, and streamline of the induced electroosmotic micropump are obtained. Studies have shown that when the cross-shaped micropump is energized, in the center of the induction electrode near the formation of a dense electric double layer, there exist four symmetrical vortices at the four corners, and they push the solution towards both outlets; it can be found that the average velocity of the solution in the cross-flow microfluidic pump is nonlinear with the applied electric field, which maybe helpful for the practical application of induced electroosmotic flow in the field of micropump.

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Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel

Cited by 24 publications

References 34 publications

Capillary electrophoresis in a fused-silica capillary with surface roughness gradient

Capillary electrophoresis in a fused-silica capillary with surface roughness gradient

Fused silica capillaries with two segments of different internal diameters and inner surface roughnesses prepared by etching with supercritical water and used for volume coupling electrophoresis

Design and Numerical Study of Micropump Based on Induced Electroosmotic Flow

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