Cation exchange membrane integrated into a microfluidic device

Svoboda, Miloš; Slouka, Zdeněk; Schrott, Walter; Šnita, Dalimil

doi:10.1016/j.mee.2009.01.019

Cited by 25 publications

(7 citation statements)

References 13 publications

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“…According to the estimates made in [40], the characteristic radius of the conducting regions on the surface of commercially manufactured by MEGA a.s. swollen samples of CM Pes cation-exchange membranes range from 0.5 to 7 μm. Similar data were obtained byhigh vacuum scanning electron microscopyfor driedsamples at magnification of 200 in [42]: SEM picture analysis of the membrane sample Ralex CM has shown that the size of conductive polymer granules varies in range from units to tens of microns. An increase in the milling time of the ion-exchanger corresponds to a decrease in the weighted average radius R of resin particles on the surface of swollen membranes by 20%.…”

Section: Surface Morphology Of Heterogeneous Membranes With Differentsupporting

confidence: 79%

A Study of Ralex Membrane Morphology by SEM

et al. 2019

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A comparative analysis of the effect of the manufacturing technology of heterogeneousion-exchange membranes Ralex CM Pes manufactured by MEGA a.s. (Czech Republic) on the structural properties of their surface and cross section by SEM was carried out. The CM Pes membrane is a composite of a sulfonated ion-exchanger with inert binder of polyethylene and reinforcing polyester fiber. In the manufacture of membranes Ralex the influence of two factors was investigated. First, the time of ion-exchange grain millingvaried at a constant resin/polyethylene ratio. Second, the ratio of the cation-exchanger and the inert binder of polyethylene varied. It has been found that the membrane surface becomes more electrically homogeneous with the growth of the ion-exchanger loading and a decrease in its particle size. With an increase in the milling time of resin grainsfrom 5 to 80 min a more than 1.5-fold decrease in their radius and in the distance between them was revealed.Besides, there is a 1.5-fold decrease in the fraction, as well as in the size of pores and structure defects. The fraction of the ion-exchange phase on the membrane surface decreases by 7%. With an increase in the resin loading from 45 to 70 wt %, the growth of the fraction of conducting regions on the surface is almost twofold, while their sizes remain practically unchanged. More significant changes in the surface structure of the studied membranes are established in comparison with the cross section. An increase in the resin content in the membranes from 45 to 70 wt % corresponds to a 43% increment of its fraction on the cross-section.The increase in the ion-exchanger content of Ralex membranes is accompanied by the growth of the fraction of macropores and structure defects on the membrane surface by 70% and a twofold decrease in the distance between conducting zones.

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Section: Surface Morphology Of Heterogeneous Membranes With Differentsupporting

confidence: 79%

A Study of Ralex Membrane Morphology by SEM

et al. 2019

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“…Although these ion-exchange membranes are mainly used in large-scale industrial processes for water treatment, they have also been integrated in microfluidic systems either to study fundamental electrokinetic processes (32)(33)(34)(35) or to act as functional elements such as pH actuators (36) or biomolecule preconcentrators (37). One of the most interesting features of ion-exchange membranes is a nonlinear current voltage curve (CVC) (Figure 1a) where two ohmic regions are connected through a limiting region, a behavior that was observed more than 60 years ago (38).…”

Section: Membrane Ion Current Circuitsmentioning

confidence: 99%

Microfluidic Systems with Ion-Selective Membranes

Slouka

Senapati

Chang

2014

Annual Rev. Anal. Chem.

105

113

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When integrated into microfluidic chips, ion-selective nanoporous polymer and solid-state membranes can be used for on-chip pumping, pH actuation, analyte concentration, molecular separation, reactive mixing, and molecular sensing. They offer numerous functionalities and are hence superior to paper-based devices for point-of-care biochips, with only slightly more investment in fabrication and material costs required. In this review, we first discuss the fundamentals of several nonequilibrium ion current phenomena associated with ion-selective membranes, many of them revealed by studies with fabricated single nanochannels/nanopores. We then focus on how the plethora of phenomena has been applied for transport, separation, concentration, and detection of biomolecules on biochips.

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“…Additional analysis for the concentration distribution in a semi-infinite domain, where at infinity the concentration has a bulk value and at the other end there exists a permselective interface has also been used in numerous works [11]. These solutions have been used to investigate the behavior of the concentration at the interface and the transition time until its complete depletion [12,13]. Also, chronopotentiometry experiments have investigated the time dependency of the electric potential [10,14,15] to a step-wise electric current.…”

Section: Introductionmentioning

confidence: 99%

Time-dependent ion transport in heterogeneous permselective systems

Green

Yossifon

2015

Phys. Rev. E

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The current study extends previous analytical and numerical solutions of chronopotentiometric response of one-dimensional systems consisting of three layers to the more realistic two-dimensional heterogeneous ion-permselective medium. An analytical solution for the transient concentration-polarization problem, under the local electroneutrality approximation and ideal permselectivity, was obtained using the Laplace transform and separation of variables. Then the two-dimensional electric potential was obtained numerically and was compared to the full Poisson-Nernst-Planck solution. It was then shown that the resultant voltage drop across the system varies between the initial Ohmic response and that of the steady-state accounting for concentration-polarization. Also, field-focusing effect in a two-dimensional system is shown to result in a faster depletion of ions at the permselective interface.

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Cation exchange membrane integrated into a microfluidic device

Cited by 25 publications

References 13 publications

A Study of Ralex Membrane Morphology by SEM

A Study of Ralex Membrane Morphology by SEM

Microfluidic Systems with Ion-Selective Membranes

Time-dependent ion transport in heterogeneous permselective systems

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