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Tetraalkylammonium Cations Conduction through a Single Nanofluidic Diode: Experimental and Theoretical Studies

Ali, Mubarak ; Ramirez, Patricio ; Nasir, Saima ; Cervera, Javier ; Mafe, Salvador ; Ensinger, Wolfgang (2017)
Tetraalkylammonium Cations Conduction through a Single Nanofluidic Diode: Experimental and Theoretical Studies.
In: Electrochimica Acta, 250
doi: 10.1016/j.electacta.2017.08.078
Article

Abstract

We describe experimentally and theoretically the concentration-dependent conduction of tetraalkylammonium (TAA+) cations through a nanofluidic diode fabricated in a polymer membrane via asymmetric track-etching techniques. This single-pore membrane exhibits current rectification characteristics because of the ionized carboxylate groups on the pore surface. We use aqueous solutions of potassium (K+), ammonium (A+), tetramethylammonium (TMA+), tetraethylammonium (TEA+), and tetrabutylammonium (TBA+) ions with concentrations ranging from 50 to 500 mM under acidic (pH 3.5) and physiological (pH 6.5) conditions. Compared with the K+ and A+ ions, the TMA+, TEA+, and TBA+ ions show relatively low rectified ion currents because the cation hydrophobicity increases with the alkyl chain. At low concentrations and acidic conditions, an inversion in the current rectification characteristics is observed, which is attributed to the adsorption of the organic cations on the pore surfaces. The experimental results can be analyzed in terms of the Poisson-Nernst-Planck equations and the geometrical and electrical single pore characteristics for the different ions, pH values, and salt concentrations employed. This theoretical approach is qualitative and could be extended further to include a self-consistent theoretical treatment of the ionic adsorption and surface charge equilibria.

Item Type: Article
Erschienen: 2017
Creators: Ali, Mubarak ; Ramirez, Patricio ; Nasir, Saima ; Cervera, Javier ; Mafe, Salvador ; Ensinger, Wolfgang
Type of entry: Bibliographie
Title: Tetraalkylammonium Cations Conduction through a Single Nanofluidic Diode: Experimental and Theoretical Studies
Language: English
Date: 1 October 2017
Publisher: Elsevier Science Publishing
Journal or Publication Title: Electrochimica Acta
Volume of the journal: 250
DOI: 10.1016/j.electacta.2017.08.078
URL / URN: https://doi.org/10.1016/j.electacta.2017.08.078
Abstract:

We describe experimentally and theoretically the concentration-dependent conduction of tetraalkylammonium (TAA+) cations through a nanofluidic diode fabricated in a polymer membrane via asymmetric track-etching techniques. This single-pore membrane exhibits current rectification characteristics because of the ionized carboxylate groups on the pore surface. We use aqueous solutions of potassium (K+), ammonium (A+), tetramethylammonium (TMA+), tetraethylammonium (TEA+), and tetrabutylammonium (TBA+) ions with concentrations ranging from 50 to 500 mM under acidic (pH 3.5) and physiological (pH 6.5) conditions. Compared with the K+ and A+ ions, the TMA+, TEA+, and TBA+ ions show relatively low rectified ion currents because the cation hydrophobicity increases with the alkyl chain. At low concentrations and acidic conditions, an inversion in the current rectification characteristics is observed, which is attributed to the adsorption of the organic cations on the pore surfaces. The experimental results can be analyzed in terms of the Poisson-Nernst-Planck equations and the geometrical and electrical single pore characteristics for the different ions, pH values, and salt concentrations employed. This theoretical approach is qualitative and could be extended further to include a self-consistent theoretical treatment of the ionic adsorption and surface charge equilibria.

Uncontrolled Keywords: tetraalkyammonium cations, biomimetic nanopore, current rectification, nanofluidic Diode, Nernst-Planck equation
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Material Analytics
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 28 Dec 2017 11:59
Last Modified: 28 Dec 2017 11:59
PPN:
Funders: M. A., S. N., and W.E. acknowledge the funding from the Hessen State Ministry of Higher Education, Research and the Arts, Germany, under the LOEWE project iNAPO., P. R., J. C., and S. M. acknowledge financial support by the Spanish Ministry of Economic Affairs and Competitiveness (MAT2015-65011-P) and FEDER.
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