Wright Andrew G, Holdcroft Steven
Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
ACS Macro Lett. 2014 May 20;3(5):444-447. doi: 10.1021/mz500168d. Epub 2014 Apr 22.
In the pursuit of stable, hydroxide ion-exchange ionomers and solid polymer electrolytes for fuel cells and electrolyzers, we present a novel, sterically C2-protected poly(benzimidazole) derivative incorporating a hexamethyl--terphenylene group. Using a new, scalable, and air-insensitive methylation procedure, -methylation of the polymer is controlled to yield an unprecedented hydroxide-stable, methanol-soluble, and water-insoluble poly(benzimidazolium) ionene. This original polymer is also soluble in aqueous ethanol, which makes it suitable for use as a processable ionomer for catalyst layers. The water uptake and ionic conductivity is correlated to the degree of methylation. The anionic conductivity reached 9.7 ± 0.6 mS cm for polymers with a 92% degree of methylation. Additionally, the hexamethyl--terphenylene unit shows interesting atropisomerism, which may influence their physical properties.
在寻求用于燃料电池和电解槽的稳定的氢氧根离子交换离聚物和固体聚合物电解质的过程中，我们展示了一种新型的、空间上具有C2保护的聚（苯并咪唑）衍生物，其含有一个六甲基-对三联苯基团。通过一种新的、可扩展的且对空气不敏感的甲基化程序，控制聚合物的甲基化，以产生一种前所未有的氢氧化物稳定、可溶于甲醇且不溶于水的聚（苯并咪唑鎓）离子烯。这种原始聚合物也可溶于乙醇水溶液，这使其适合用作催化剂层的可加工离聚物。吸水率和离子电导率与甲基化程度相关。对于甲基化程度为92%的聚合物，阴离子电导率达到9.7±0.6 mS/cm。此外，六甲基-对三联苯单元表现出有趣的阻转异构现象，这可能会影响它们的物理性质。
