Polybenzimidazolium hydroxides - Structure, stability and degradation

Dirk Henkensmeier, Hyeong Rae Cho, Hyoung Juhn Kim, Carolina Nunes Kirchner, Janine Leppin, Alexander Dyck, Jong Hyun Jang, Eunae Cho, Suk Woo Nam, Tae Hoon Lim

Research output: Contribution to journalArticlepeer-review

95 Citations (Scopus)


Polybenzimidazolium hydroxides are of potential interest for the use in alkaline anion exchange membrane fuel cells (AAEMFC). Introduction of an ether group in para-position of the 2-phenyl substituent improves the mesomeric stabilization of imidazolium cations, and O-PBI seems to be more stable than meta-PBI under alkaline conditions. NMR, IR and XPS analysis show a structural change when the iodide form is exchanged into the hydroxide form. Surprisingly, this structural change is subject to a pH sensitive equilibrium and the pure imidazolium form is retained immediately when the pH is lowered. The molecular structure at high pH is either the 2-carbinol or the amine-amide. Further hydrolysis necessitates excess hydroxide.

Original languageEnglish
Pages (from-to)264-272
Number of pages9
JournalPolymer Degradation and Stability
Issue number3
Publication statusPublished - 2012 Mar

Bibliographical note

Funding Information:
The authors would like to thank GOI and “E-Bank” program of Korea Institute of Science and technology. Also, this work was supported by a Grant ( M2009010025 ) from the fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy (MKE), Republic of Korea .


  • 2-Phenyl-imidazolium hydroxide
  • Anion exchange membrane
  • Hydrolysis
  • NMR
  • Polybenzimidazole
  • Polymer electrolyte

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Polymers and Plastics
  • Materials Chemistry


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