Partially fluorinated poly(arylene ether)s: Investigation of the dependence of monomeric structures on polymerisability and degradation during sulfonation

A series of partially fluorinated poly(arylene ether)s with systematical structure variations (variations in the (bi)phenylene, bisphenol moiety, and the fluorine content) was synthesized and characterized. Main objective of this contribution was the investigation of structure-property relationships of the different polymer structures, and how the chemical structure of the aromatic monomers influences (1) polymerisability of the monomers; (2) chemical and thermal stability of the poly(arylene ether)s, and (3) properties of the referring sulfonated polymers, particularly their chemical and mechanical stability. Polymers from this series comprising high molecular weight and excellent film-forming properties were targeted to various sulfonation routes, and their degradation behavior during sulfonation was investigated by gel permeation chromatography (GPC). Finally, (polybenzimidazole blend) membrane properties of the most promising candidates for potential application in polymer electrolyte membrane fuel cells were evaluated. The best of the investigated blend membranes was investigated in an air-breathing DMFC and yielded markedly improved performance, compared to Nafion®105. This study gives both insight into structure-property-relationships and directions for future polymer and membrane developments.