Parametrical studies of electroosmotic transport characteristics in submicrometer channels

Postler, Tomáš; Slouka, Zdeněk; Svoboda, Miloš; Přibyl, Michal; Šnita, Dalimil

doi:10.1016/j.jcis.2007.10.056

Cited by 34 publications

(27 citation statements)

References 58 publications

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“…The mathematical model is based on the approach used in works. 27,28 The velocity v and pressure p fields are described by the Stokes equation 29 ͑Reynolds number is close to zero͒ containing the coulomb force term and by the continuity equation for an incompressible Newtonian fluid…”

Section: -5mentioning

confidence: 99%

Study on surface properties of PDMS microfluidic chips treated with albumin

Schrott¹,

Slouka²,

Červenka³

et al. 2009

Biomicrofluidics

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Electrokinetic properties and morphology of PDMS microfluidic chips intended for bioassays are studied. The chips are fabricated by a casting method followed by polymerization bonding. Microchannels are coated with 1% solution of bovine serum albumin ͑BSA͒ in Tris buffer. Albumin passively adsorbs on the PDMS surface. Electrokinetic characteristics ͑electro-osmotic velocity, electro-osmotic mobility, and zeta potential͒ of the coated PDMS channels are experimentally determined as functions of the electric field strength and the characteristic electrolyte concentration. Atomic force microscopy ͑AFM͒ analysis of the surface reveals a "peak and ridge" structure of the protein layer and an imperfect substrate coating. On the basis of the AFM observation, several topologies of the BSA-PDMS surface are proposed. A nonslip mathematical model of the electro-osmotic flow is then numerically analyzed. It is found that the electrokinetic characteristics computed for a channel with the homogeneous distribution of a fixed electric charge do not fit the experimental data. Heterogeneous distribution of the fixed electric charge and the surface roughness is thus taken into account. When a flat PDMS surface with electric charge heterogeneities is considered, the numerical results are in very good agreement with our experimental data. An optimization analysis finally allowed the determination of the surface concentration of the electric charge and the degree of the PDMS surface coating. The obtained findings can be important for correct prediction and possibly for robust control of behavior of electrically driven PDMS microfluidic chips. The proposed method of the electro-osmotic flow analysis at surfaces with a heterogeneous distribution of the surface electric charge can also be exploited in the interpretation of experimental studies dealing with protein-solid phase interactions or substrate coatings.

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Section: -5mentioning

confidence: 99%

Study on surface properties of PDMS microfluidic chips treated with albumin

Schrott¹,

Slouka²,

Červenka³

et al. 2009

Biomicrofluidics

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“…(Kim et al 2007;Kelly et al 2009). This phenomenon as applied to micro/nano fluidic systems has also been considered theoretically in a number of recent publications (Postler et al 2008;Zangle et al 2010;Yaroshchuk et al 2011). …”

Section: Introductionmentioning

confidence: 95%

Hydrodynamic dispersion in long microchannels under conditions of electroosmotic circulation: II. Electrolytes

Bernal

Kovalchuk

Zholkovskiy

et al. 2016

Microfluid Nanofluid

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This work describes the steady state transport of an electrolyte due to a stationary concentration difference in straight long channels under conditions of electroosmotic circulation. The electroosmotic flow is induced due to the slip produced at the charged channel walls. This flow is assumed to be compensated by a pressure-driven counter-flow so that the net volume flow through the channel is exactly zero. Owing to the concentration dependence of electroosmotic slip there is an involved coupling between the solute transfer, hydrodynamic flow and charge conservation. Nevertheless, for such a system the Taylor-Aris Dispersion (TAD) theory is shown to be approximately applicable locally within an inner part of the channel for a wide range of Péclet numbers (Pe) irrespective of the concentration difference. Numerical simulations reveal only small deviations from analytical solutions for the inner part of the channel. The breakdown of TAD theory occurs within boundary regions near the channel ends and -is related to the variation of the dispersion mechanism from the purely molecular diffusion at the channel ends to the hydrodynamic dispersion within the inner part of the channel. This boundary region is larger at the lower-concentration channel edge and its size increases nearly linearly with Pe number. It is possible to derive a simple analytical approximation for the inner profile of cross-section-averaged electrolyte concentration in terms of only few parameters, determined numerically. Such analytical approximations can be useful for experimental studies of concentration-polarization phenomena in long micro-channels.

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“…The DC electroosmotic pumps are widely exploited in experimental and commercial microfluidic devices, e.g., see reviews (Becker & Locascio, 2002, Beebe et al, 2002, Bilitewski et al, 2003, Chang & Yang, 2007, Laser & Santiago, 2004. The reaction transport processes in such devices have been also modeled and analyzed, e.g., (Erickson, 2005, He & Hauan, 2006, Postler et al, 2008. The DC devices suffer from a serious disadvantage: the potential difference imposed on microdevices usually has to be in the order of kilovolts.…”

Section: Figure 2 Principle Of DC Electroosmosis In a Microchannelmentioning

confidence: 99%

“…In such case, it is necessary to specify the reference pressure in a single point of the system. The used sets of boundary conditions for the microfluidic systems described here can be found in (Postler et al, 2008, Pribyl et al, 2006a, Pribyl et al, 2006b. The model equations are usually transformed into a dimensionless form.…”

Section: Basic Equations and Boundary Conditionsmentioning

confidence: 99%