PUB - Publikationen an der Universität Bielefeld

A novel polymer featuring difluoromethylene phosphonic acid functions was prepared by free radical polymerization of a styrene monomer that is decorated by phosphonic ester groups. The obtained polymer was analyzed by gel permeation chromatography, differential scanning calorimetry, and spectroscopy (NMR, infrared). Treatment of the polymeric phosphonic ester with Me3SiBr led to an exchange of the ethyl groups by trimethylsilyl units in the P-containing part of the material. Desilylation to the free phosphonic acid functions was effected by water. The ion exchange capacity was determined to be 7.3mmol/g by titration with 0.1M NaOH. The proton conductivity in the anhydrous state was studied by electrochemical impedance spectroscopy. The conductivity of 1.76 x 10(-5) S cm(-1) at 120 degrees C is well comparable with that of Nafion (7.66 x 10(-5) S cm(-1) at 120 degrees C), and renders this polymeric phosphonic acid as a promising candidate for proton conduction applications. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46765.