Inorganic-Organic Hybrid Anion Conducting Membranes Based on Ammonium-Functionalized Polyethylene Pyrrole-Polyethylene Ketone Copolymer

Abstract New inorganic-organic hybrid anion exchange membranes are produced after incorporation of tantalum oxide into trimethylammonium-functionalized polyethylene pyrrole-co-polyethylene ketone (functionalized polyketone, FPK), obtained by the chemical modification of a polyketone polymer. The influence of tantalum oxide fillers on the properties of the synthesized membranes is investigated. The interaction between inorganic fillers and the polymer chains is studied using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). The thermal analysis of the FPK membranes reveals they are thermally stable at up to 250°C. However, the incorporation of the inorganic fillers reduces the thermal stability. Modulated Differential Scanning Calorimetry (MDSC) results indicate that the inclusion of inorganic fillers leads to an increase in crystallinity. This study reports that the properties of the bulk polymer can be tuned by controlling the degree of functionalization and content of inorganic fillers, as confirmed by Near Ambient Pressure X-Ray Photoelectron Spectroscopy (NAP-XPS) studies. Finally, Broadband Electrical Spectroscopy (BES) studies demonstrate that the hybrid membranes are characterized by several polarization phenomena contributing to the overall ion conductivity of the material, which at RT is of 1.46 and 1.61 mS cm?1 for the FPK cast membrane and the hybrid membrane with 5.0 wt.% of Ta2O5 filler, respectively.