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Effect of Polymer Composition and Water Content on Proton Conductivity in Vinyl Benzyl Phosphonic Acid—4‐Vinyl Pyridine Copolymers
Author(s) -
Jiang Fengjing,
Kaltbeitzel Anke,
Fassbender Birgit,
Brunklaus Gunther,
Pu Hongting,
Meyer Wolfgang H.,
Spiess Hans W.,
Wegner Gerhard
Publication year - 2008
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200800375
Subject(s) - copolymer , proton , conductivity , polymer chemistry , chemistry , polymer , vinyl polymer , pyridine , organic chemistry , physics , quantum mechanics
The proton conductivities of poly(vinylbenzyl phosphonic acid) (PVBPA) homopolymer and its statistical copolymers with 4‐vinyl pyridine [poly(VBPA‐ stat ‐4VP)s] are comprehensively studied in this work. Temperature and composition‐dependent “dry” proton conductivities of the copolymers have been determined and the self‐condensation of phosphonic acid groups has been quantified. The results show that the intrinsic proton conductivities of poly(VBPA‐ stat ‐4VP)s and PVBPA are quite low at 150 °C and exhibit time‐dependent changes due to anhydride formation at elevated temperatures. The effect of polymer composition on proton conduction shows a minimum at a 1:1 molar ratio of proton donor and acceptor groups and is discussed on the basis of the p K a values of the electrolyte species. A trace amount of water significantly increases conductivity probably due to additional hydronium ion diffusion and water bridging effects. Water content and proton conductivities of poly(VBPA‐ stat ‐4VP)s are determined at different relative humidities. High amounts of water are absorbed at high humidities leading to high proton conductivities.