This review is focused on the design and synthesis of new high‐temperature polymer electrolytes based on aromatic polyethers bearing polar pyridine moieties in the main chain. Such materials are designed to be used in polymer electrolyte fuel cells operating at temperatures higher than 100 °C. New monomers and polymers have been synthesized and characterized within this field in respect of their suitability for this specific application. Copolymers with optimized structures in order to combine excellent film‐forming properties with high mechanical, thermal and oxidative stability and controlled acid uptake have been synthesized which, after doping with phosphoric acid, result in ionically conducting membranes. Such materials have been studied in respect of their conductivity under various conditions and used for the construction of membrane‐electrode assemblies (MEAs) which are used for fuel cells operating at temperatures up to 180 °C. New and improved, in terms of oxidative stability and mechanical properties in the doped state, polymeric membranes have been synthesized and used effectively for MEA construction and single‐cell testing. Copyright © 2009 Society of Chemical Industry

Novel pyridine-based aromatic copolymers containing 4,4′-biphenol or hydroquinone groups in the main chain were synthesized and characterized as polymer electrolytes for proton exchange membrane fuel cells (PEMFCs). Depending on the copolymer composition and pyridine monomer content in most cases soluble and high molecular weight copolymers were obtained. Flexible membrane films were prepared by casting N,Ndimethylacetamide (DMA C ) solutions of copolymers. 1 H NMR and size exclusion chromatography were used to characterize the structures of the copolymers. High glass transition temperatures (T g s) and decomposition temperatures (T d s) were observed using dynamic mechanical analysis and thermogravimetry, respectively. The oxidative stability of the membranes was examined with Fenton′s test. The doping ability and the proton conductivity of the membranes were also studied and the new copolymers can be potential candidates as new polymeric electrolyte materials for proton exchange membrane fuel cells. Finally, membrane electrode assemblies (MEAs) were constructed and tested in 25 cm 2 single cell at different temperatures showing promising performance.