Abstract
Membrane materials with semipermeability for anions or for cations are of interest in electrochemical and nanofluidic separation and purification technologies. In this study, partially hydrolyzed polyacrylonitrile (phPAN) is investigated as a pH-switchable anion/cation conductor. When switching from anionic to cationic semipermeability, 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 μm thick polyethylene-terephthalate (PET) film substrate. Therefore, ionic rectifier behavior can be tuned and used to monitor and characterize semipermeability. 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 the 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 language | English |
|---|---|
| Pages (from-to) | 3214-3224 |
| Number of pages | 11 |
| Journal | ACS applied materials & interfaces |
| Volume | 12 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 15 Jan 2020 |
Keywords
- double layer
- ion channel
- ion gating
- ionic rectifier
- membrane
- polyacrylonitrile
- steady state voltammetry
ASJC Scopus subject areas
- General Materials Science