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Switching Anionic and Cationic Semi-Permeability in Partially Hydrolyzed Polyacrylonitrile: A pH-Tunable Ionic Rectifier

Tshwenya, L., Marken, F., Mathwig, K. & Arotiba, O. A., 2020, In : ACS Applied Materials & Interfaces. 12, 2, p. 3214-3224 11 p.

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  • Switching Anionic and Cationic Semipermeability in Partially Hydrolyzed Polyacrylonitrile: A pH-Tunable Ionic Rectifier

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DOI

Membrane materials with semi-permeability for anions or for cations are of interest in electrochemical and nanofluidic separation and purification technologies. In this study, partially hydrolyzed poly-acrylonitrile (phPAN) is investigated as a pH-switchable anion/cation conductor. When switching from anionic to cationic semi-permeability, also the ionic current rectification effect switches for phPAN materials deposited asymmetrically onto a 5, 10, 20, or 40 µm diameter microhole in a 6 m thick polyethylene-terephthalate (PET) film substrate. Therefore, ionic rectifier behavior can be tuned and used to monitor and characterize semi-permeability. Effects of electrolyte type and concentration, and pH (relative to the zeta potential at approximately 3.1) are investigated by voltammetry, chronoamperometry, and impedance spectroscopy. A computational model provides good qualitative agreement with observed electrolyte concentration data. High rectification effects are observed for both cations (pH > 3.1) and anions (pH < 3.1), but only at relatively low ionic strengths.

Original languageEnglish
Pages (from-to)3214-3224
Number of pages11
JournalACS Applied Materials & Interfaces
Volume12
Issue number2
Early online date18-Dec-2019
Publication statusPublished - 2020

ID: 111363962