The apparent hydrodynamic slip of polymer solutions and its implications in electrokinetics

Berli, Claudio L. A.

doi:10.1002/elps.201200476

Cited by 18 publications

(8 citation statements)

References 113 publications

(178 reference statements)

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“…However, all these studies have been limited to Newtonian fluids only, in which fluid electroosmosis and particle electrophoresis are simply a linear function of the applied DC electric field. As many of the fluids used in capillary electrophoresis and microfluidic devices, such as polymer solutions and bodily fluids, are complex, [24][25][26][27][28][29][30][31][32] it is important from the aspects of both fundamentals and applications to study how electrokinetic particle focusing may be affected by the fluid non-Newtonian effects.…”

Section: Introductionmentioning

confidence: 99%

Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel

DuBose

Joo

et al. 2015

Biomicrofluidics

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Focusing suspended particles in a fluid into a single file is often necessary prior to continuous-flow detection, analysis, and separation. Electrokinetic particle focusing has been demonstrated in constricted microchannels by the use of the constrictioninduced dielectrophoresis. However, previous studies on this subject have been limited to Newtonian fluids only. We report in this paper an experimental investigation of the viscoelastic effects on electrokinetic particle focusing in non-Newtonian polyethylene oxide solutions through a constricted microchannel. The width of the focused particle stream is found NOT to decrease with the increase in DC electric field, which is different from that in Newtonian fluids. Moreover, particle aggregations are observed at relatively high electric fields to first form inside the constriction. They can then either move forward and exit the constriction in an explosive mode or roll back to the constriction entrance for further accumulations. These unexpected phenomena are distinct from the findings in our earlier paper [Lu et al., Biomicrofluidics 8, 021802 (2014)], where particles are observed to oscillate inside the constriction and not to pass through until a chain of sufficient length is formed. They are speculated to be a consequence of the fluid viscoelasticity effects.

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Section: Introductionmentioning

confidence: 99%

Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel

DuBose

Joo

et al. 2015

Biomicrofluidics

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“…Similar to the process of solving the first-order problem, based on the boundary conditions (14), (20), and(21) and the solutions (18), (23), the solution to the second-order problem can be assumed to take the form of the following (the detailed processes are given in Supporting Information):…”

Section: The Second-order Solutionsmentioning

confidence: 99%

“…The EOF of Newtonian fluid in various smooth microchannels has been studied theoretically, numerically, and experimentally, by many researchers. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] In practice, there are many roughnesses on surfaces of real channel walls, because the fabrication process or the adsorption of other species such as macromolecules can cause roughnesses on the wall of channel. Since the 1970s a number of researchers studied the influence of wall roughness on laminar flow.…”

Section: Introductionmentioning

confidence: 99%

Electroosmotic flow through a microparallel channel with 3D wall roughness

et al. 2015

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In this paper, a perturbation method is introduced to study the EOF in a microparallel channel with 3D wall roughness. The corrugations of the two walls are periodic sinusoidal waves of small amplitude in two directions either in phase or half-period out of phase. Based on linearized Poisson-Boltzmann equation, Laplace equation, and the Navier-Stokes equations, the perturbation solutions of velocity, electrical potential, and volume flow rate are obtained. By using numerical computation, the influences of the wall corrugations on the mean velocity are analyzed. The variations of electrical potential, velocity profile, mean velocity, and their dependences on the wave number α and β of wall corrugations in two directions, the nondimensional electrokinetic width K, and the zeta potential ratio between the lower wall and the upper wall ς are analyzed graphically.

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“…The effect of solvent rheology has also been a focus of several recent studies in electrokinetics, which depict several non-trivial phenomena such as augmentation in the flow rate, power harvesting capability etc. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] The manipulation, trapping and mixing of biofluids such as protein chains, colloidal and cell suspensions etc. play a part in microrheometers, micromixers, micronozzles etc.…”

Section: Introductionmentioning

confidence: 99%

Consistent prediction of streaming potential in non-Newtonian fluids: the effect of solvent rheology and confinement on ionic conductivity

Bandopadhyay

Chakraborty

2015

Phys. Chem. Chem. Phys.

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By considering an ion moving inside an imaginary sphere filled with a power-law fluid, we bring out the implications of the fluid rheology and the influence of the proximity of the other ions towards evaluating the conduction current in an ionic solution. We show that the variation of the conductivity as a function of the ionic concentration is both qualitatively and quantitatively similar to that predicted by the Kohlrausch law. We then utilize this consideration for estimating streaming potentials developed across narrow fluidic confinements as a consequence of the transport of ions in a convective medium constituting a power-law fluid. These estimates turn out to be in sharp contrast to the classical estimates of streaming potential for non-Newtonian fluids, in which the effect of rheology of the solvent is merely considered to affect the advection current, disregarding its contributions to the conduction current. Our results have potential implications of devising a new paradigm of consistent estimation of streaming potentials for non-Newtonian fluids, with combined considerations of the confinement effect and fluid rheology in the theoretical calculations.

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The apparent hydrodynamic slip of polymer solutions and its implications in electrokinetics

Cited by 18 publications

References 113 publications

Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel

Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel

Electroosmotic flow through a microparallel channel with 3D wall roughness

Consistent prediction of streaming potential in non-Newtonian fluids: the effect of solvent rheology and confinement on ionic conductivity

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