Importance of Electrostatic Interactions in The Mobility of Cations in Nafion
DSpace at IIT Bombay
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Title |
Importance of Electrostatic Interactions in The Mobility of Cations in Nafion
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Creator |
IYER, ESS
DATTA, A |
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Subject |
FUEL-CELL MEMBRANES
NORMALIZED EMISSION-SPECTROSCOPY ION-EXCHANGE MEMBRANES STATE PROTON-TRANSFER PERFLUORINATED IONOMER REVERSE MICELLES ROOM-TEMPERATURE WATER DYNAMICS TRANSPORT CONDUCTIVITY |
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Description |
A molecular level understanding of the mobility of cations in the Nafion membrane has been attempted, using the excited state proton transfer (ESPT) process in the fluorescent probe Coumarin 102. ESPT is hindered significantly upon decreasing the water content. Using TRANES (time-resolved area normalized emission spectroscopy), the evolution of the ESPT state is clearly observed over hundreds of picoseconds in lower water content, implying that ESPT is hindered even in the nanovolume probed by the dye. Most remarkably, in the partially dried membrane, the predominant fluorescent species is the zwitterionic form, generated by excited state deprotonation of the cationic form. This implies that the molecule loses a proton from its nitrogen center in the excited state, as usual, but cannot recapture it readily at the oxygen center, at low water contents. This phenomenon is rationalized in light of an increased electrostatic attraction that is experienced by cations upon drying.
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Publisher |
AMER CHEMICAL SOC
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Date |
2012-06-26T09:04:47Z
2012-06-26T09:04:47Z 2011 |
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Type |
Article
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Identifier |
JOURNAL OF PHYSICAL CHEMISTRY B,115(27)8707-8712
1520-6106 http://dx.doi.org/10.1021/jp203814b http://dspace.library.iitb.ac.in/jspui/handle/100/14254 |
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Language |
English
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