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Fabrication of Single Cylindrical Au-Coated Nanopores with Non-Homogeneous Fixed Charge Distribution Exhibiting High Current Rectifications

Nasir, Saima and Ali, Mubarak and Ramirez, Patricio and Gomez, Vicente and Oschmann, Bernd and Muench, Falk and Nawaz Tahir, Muhammad and Zentel, Rudolf and Mafe, Salvador and Ensinger, Wolfgang (2014):
Fabrication of Single Cylindrical Au-Coated Nanopores with Non-Homogeneous Fixed Charge Distribution Exhibiting High Current Rectifications.
In: ACS Applied Materials & Interfaces, pp. 12486-12494, 6, (15), [Online-Edition: http://dx.doi.org/10.1021/am502419j],
[Article]

Abstract

We designed and characterized a cylindrical nanopore that exhibits high electrochemical current rectification ratios at low and intermediate electrolyte concentrations. For this purpose, the track-etched single cylindrical nanopore in polymer membrane was coated with a gold (Au) layer via electroless plating technique. Then, a non-homogeneous fixed charge distribution inside the Au-coated nanopore was obtained by incorporating thiol-terminated uncharged poly(N-isopropylacrylamide) chains in series to poly(4-vinylpyridine) chains, which were positively charged at acidic pH values. The functionalization reaction was checked by measuring the current?voltage curves prior to and after the chemisorption of polymer chains. The experimental nanopore characterization included the effects of temperature, adsorption of chloride ions, electrolyte concentration, and pH of the external solutions. The results obtained are further explained in terms of a theoretical continuous model. The combination of well-established chemical procedures (thiol and self-assembled monolayer formation chemistry, electroless plating, ion track etching) and physical models (two-region pore and Nernst?Planck equations) permits the obtainment of a new nanopore with high current rectification ratios. The single pore could be scaled up to multipore membranes of potential interest for pH sensing and chemical actuators.

Item Type: Article
Erschienen: 2014
Creators: Nasir, Saima and Ali, Mubarak and Ramirez, Patricio and Gomez, Vicente and Oschmann, Bernd and Muench, Falk and Nawaz Tahir, Muhammad and Zentel, Rudolf and Mafe, Salvador and Ensinger, Wolfgang
Title: Fabrication of Single Cylindrical Au-Coated Nanopores with Non-Homogeneous Fixed Charge Distribution Exhibiting High Current Rectifications
Language: English
Abstract:

We designed and characterized a cylindrical nanopore that exhibits high electrochemical current rectification ratios at low and intermediate electrolyte concentrations. For this purpose, the track-etched single cylindrical nanopore in polymer membrane was coated with a gold (Au) layer via electroless plating technique. Then, a non-homogeneous fixed charge distribution inside the Au-coated nanopore was obtained by incorporating thiol-terminated uncharged poly(N-isopropylacrylamide) chains in series to poly(4-vinylpyridine) chains, which were positively charged at acidic pH values. The functionalization reaction was checked by measuring the current?voltage curves prior to and after the chemisorption of polymer chains. The experimental nanopore characterization included the effects of temperature, adsorption of chloride ions, electrolyte concentration, and pH of the external solutions. The results obtained are further explained in terms of a theoretical continuous model. The combination of well-established chemical procedures (thiol and self-assembled monolayer formation chemistry, electroless plating, ion track etching) and physical models (two-region pore and Nernst?Planck equations) permits the obtainment of a new nanopore with high current rectification ratios. The single pore could be scaled up to multipore membranes of potential interest for pH sensing and chemical actuators.

Journal or Publication Title: ACS Applied Materials & Interfaces
Volume: 6
Number: 15
Divisions: 11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Material Analytics
11 Department of Materials and Earth Sciences
Date Deposited: 25 Aug 2014 14:29
Official URL: http://dx.doi.org/10.1021/am502419j
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