Ion current rectification in a fluidic bipolar nanochannel with smooth junction

Singh, Kunwar P.; Kumari, Kusum; Kumar, Manoj

doi:10.1063/1.3627181

Cited by 20 publications

(18 citation statements)

References 24 publications

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“…Although bipolar nanopores have been studied with the PNP theory extensively [54,36,23,55,56,2,57,58,59,60,61,62,63,64], we are not aware of any paper where this system is examined by molecular simulations apart from our previous study for a rectifying bipolar ion channel [65] and our parallel study where we compare to PNP [66]. We are aware only of a few MD studies [67,68,69,70,71,72] for other types of nanopores.…”

Section: Questionsmentioning

confidence: 99%

Multiscale modeling of a rectifying bipolar nanopore: explicit-water versus implicit-water simulations

Ható

Valiskó

Kristóf

et al. 2017

Phys. Chem. Chem. Phys.

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In a multiscale modeling approach, we present computer simulation results for a rectifying bipolar nanopore at two modeling levels. In an all-atom model, we use explicit water to simulate ion transport directly with the molecular dynamics technique. In a reduced model, we use implicit water and apply the Local Equilibrium Monte Carlo method together with the Nernst-Planck transport equation. This hybrid method makes the fast calculation of ion transport possible at the price of lost details. We show that the implicit-water model is an appropriate representation of the explicit-water model when we look at the system at the device (i.e., input vs. output) level. The two models produce qualitatively similar behavior of the electrical current for different voltages and model parameters. Looking at the details of concentration and potential profiles, we find profound differences between the two models. These differences, however, do not influence the basic behavior of the model as a device because they do not influence the z-dependence of the concentration profiles which are the main determinants of current. These results then address an old paradox: how do reduced models, whose assumptions should break down in a nanoscale device, predict experimental data? Our simulations show that reduced models can still capture the overall device physics correctly, even though they get some important aspects of the molecular-scale physics quite wrong; reduced models work because they include the physics that is necessary from the point of view of device function. Therefore, reduced models can suffice for general device understanding and device design, but more detailed models might be needed for molecular level understanding.

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Section: Questionsmentioning

confidence: 99%

Multiscale modeling of a rectifying bipolar nanopore: explicit-water versus implicit-water simulations

Ható

Valiskó

Kristóf

et al. 2017

Phys. Chem. Chem. Phys.

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“…However, this is not a prerequisite of CICP and even a relatively weak, nonideal permselectivity can give rise to it. This has been confirmed by numerous theoretical and experimental studies dealing with the CICP of micro/nanointerfaces, in particular, in the so‐called nanofluidic diodes . A considerable part of theoretical studies neglected volume transfer.…”

Section: Introductionmentioning

confidence: 78%

“…For macroscopically homogeneous nanoblocks (no explicit dependence of transport coefficients on the macroscopic coordinate, x), the integration over the space variable in Equation (23) can be replaced by the integration over the virtual salt concentration by using Equation (9). Besides, we substitute the expression for the effective salt flux of Equation (12). As a result, the problem is solved in quadratures, and reduced to this system of transcendental equations for the volume flux, j v , and interface concentration, c i .…”

Section: Theorymentioning

confidence: 99%

Current‐Induced Concentration Polarization of Nanoporous Media: Role of Electroosmosis

Yaroshchuk

Bondarenko

2018

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Current-induced concentration polarization of nanoporous media is explored theoretically by using approach of local thermodynamic equilibrium within nanopore cross-sections. The problem is solved in quadratures in terms of irreversible thermodynamics. The phenomenological coefficients are further specified by using capillary space-charge model for straight slit-like and cylindrical capillaries. This analysis reveals several novel features of current-induced concentration polarization related to the (electro)osmotic volume transfer. It confirms the previous finding that volume transfer can suppress the limiting-current phenomena but obtains more accurate criteria for this. In particular, it shows that the critical nanopore size and/or electrolyte concentration depend on the nanoporous-medium relative thickness. Under no-limiting-current conditions, the salt concentration at the interface between nanoporous medium and unstirred layer is a nonmonotone function of current density. This gives rise to unconventional current-voltage characteristics. Moreover, under certain conditions, the analysis predicts the existence of ranges of "prohibited" current densities where the problem does not have 1D stationary solution, which could give rise to a kind of "phase separation" with coexisting zones of different local current densities corresponding to the same voltage. Besides the advanced understanding of current-induced concentration polarization of nanoporous media, this analysis provides guidelines for the optimization of sample preconcentration systems in (bio)chemical microanalysis.

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“…Moreover, Singh et al. 77 showed that the rectification effect in a bipolar channel increases with increasing junction sharpness due to an increasing unipolar characteristic of the electrolyte.…”

Section: Applicationsmentioning

confidence: 99%

Fundamentals and Modeling of Electrokinetic Transport in Nanochannels

Yeh

Wang

Chang

et al. 2014

Israel Journal of Chemistry

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When the channel size approaches the thickness of the charged layer (typically, ∼10–100 nm), the resulting molecular and non‐equilibrium effects are markedly different from those observed in larger channels and have a significant effect on the transport behavior of solutes and solvents. As a result, the problem of modeling fluidic behavior at the nanoscale has attracted increasing interest in recent years. This review introduces the fundamental theories and principles associated with electrokinetic transport and molecular dynamics modeling, and discusses various applications of nanofluidic devices in the physics, mechanics, and chemistry fields.

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Ion current rectification in a fluidic bipolar nanochannel with smooth junction

Cited by 20 publications

References 24 publications

Multiscale modeling of a rectifying bipolar nanopore: explicit-water versus implicit-water simulations

Multiscale modeling of a rectifying bipolar nanopore: explicit-water versus implicit-water simulations

Current‐Induced Concentration Polarization of Nanoporous Media: Role of Electroosmosis

Fundamentals and Modeling of Electrokinetic Transport in Nanochannels

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