Journal of Polymer Science Part B: Polymer Physics, Vol.57, No.11, 700-712, 2019
The impact of alkyl tri-methyl ammonium side chains on perfluorinated ionic membranes for electrochemical applications
Three different perfluorinated type polymers as anion exchange membranes for electrochemical applications were studied. They have a sulfonamide linkage to a spacer methylene chain attached to a tri-methyl ammonium cation, specifically using a three carbon spacer chain (PFAEM_H_C3), and methylated imide polymers with three (PFAEM_CH3_C3) and six carbon spacer chain (PFAEM_CH3_C6). There are significant number of zwitterionic side chains in the PFAEM_H_C3 polymer and very few in the PFAEM_CH3_C3 or the PFAEM_CH3_C6 polymer. They have similar halide conductivity, but the PFAEM_CH3_C6 showed highest OH- conductivity, 122 mS cm(-1) at 80 degrees C and 95% RH. The larger spacer chain polymer, PFAEM_CH3_C6 has a higher water uptake value (lambda = 9) compared to PFAEM_CH3_C3(lambda = 7) at 60 degrees C and 95% RH in the Cl- form. Therefore, it has a larger domain spacing of 4.9 nm versus 4.1 nm from small angle X-ray scattering data. The polymer was characterized by FTIR and DFT was used to fully assign the spectra. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019
Keywords:anion exchange membranes;electrochemical applications;electrochemistry;fuel cells;perfluorinated AEMs;polyelectrolytes;polytetrafluoroethylene