Switching Anionic and Cationic Semi-Permeability in Partially Hydrolyzed Polyacrylonitrile: A pH-Tunable Ionic RectifierTshwenya, L., Marken, F., Mathwig, K. & Arotiba, O. A., 2020, In : ACS Applied Materials & Interfaces. 12, 2, p. 3214-3224 11 p.
Research output: Contribution to journal › Article › Academic › peer-review
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.
|Number of pages||11|
|Journal||ACS Applied Materials & Interfaces|
|Early online date||18-Dec-2019|
|Publication status||Published - 2020|