Quaternary Ammonium-Bearing Perfluorinated Polymers for Anion Exchange Membrane Applications

• Published in: Membranes (Basel) Vol. 10; no. 11; p. 306
• Main Authors: Lee, Seunghyun, Lee, Hyejin, Yang, Tae-Hyun, Bae, Byungchan, Tran, Nguyen Anh Thu, Cho, Younghyun, Jung, Namgee, Shin, Dongwon
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26-10-2020; MDPI
• Subjects: Ammonium; Anion exchange; anion exchange membrane; Anion exchanging; Conductivity; Deionization; Extreme values; flow-electrode capacity deionization; Fluorides; High temperature; Hydrocarbons; Hydrophilicity; Hydrophobicity; ion conductivity; Ion exchange; Membranes; Morphology; N-Methyl-2-pyrrolidone; Organic solvents; perfluorinated polymer; Polymers; Reagents; Spectrum analysis; Transmission electron microscopy; Water uptake; United States > US; anion exchange membrane; ion conductivity; flow-electrode capacity deionization; morphology; perfluorinated polymer
• ISSN: 2077-0375; 2077-0375
• DOI: 10.3390/membranes10110306

Perfluorinated polymers are widely used in polymer electrolyte membranes because of their excellent ion conductivity, which are attributed to the well-defined morphologies resulting from their extremely hydrophobic main-chains and flexible hydrophilic side-chains. Perfluorinated polymers containing quaternary ammonium groups were prepared from Nafion- and Aquivion-based sulfonyl fluoride precursors by the Menshutkin reaction to give anion exchange membranes. Perfluorinated polymers tend to exhibit poor solubility in organic solvents; however, clear polymer dispersions and transparent membranes were successfully prepared using
-methyl-2-pyrrolidone at high temperatures and pressures. Both perfluorinated polymer-based membranes exhibited distinct hydrophilic-hydrophobic phase-separated morphologies, resulting in high ion conductivity despite their low ion exchange capacities and limited water uptake properties. Moreover, it was found that the capacitive deionization performances and stabilities of the perfluorinated polymer membranes were superior to those of the commercial Fumatech membrane.