Microheterogeneity in Native and Cation-Exchanged Nafion Membranes
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- 作者：E. Siva Subramaniam Iyer ; Anindya Datta
- 刊名：The Journal of Physical Chemistry B
- 出版年：2012
- 出版时间：August 23, 2012
- 年：2012
- 卷：116
- 期：33
- 页码：9992-9998
- 全文大小：444K
- 年卷期：v.116,no.33(August 23, 2012)
- ISSN：1520-5207
文摘
2-(4鈥?Pyridyl)benzimidazole (4PBI) has been used to investigate the microheterogeneity of water nanochannels of Nafion membranes at two different hydration levels. Native as well as cation-exchanged Nafion membranes are found to protonate one of the two monoprotonated forms of 4PBI selectively. In native membranes and in those in which H3O+ ions are replaced by (CH3)4N+ ions, the pyridyl nitrogen is protonated preferentially. In Na+-exchanged membranes, however, the benzimidazole nitrogen is protonated selectively. Unlike other fluorescent probes used in earlier studies, 4PBI can differentiate between the two different cation-exchanged membranes at lower as well as higher hydration levels.