ISSN:
0887-6266
Keywords:
positron annihilation
;
free-volume
;
Nafion
;
free-volume size distribution
;
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
We report a new result of free-volume hole size distribution in water and ethanol-swollen Nafion-117 polymer. With the increase in water content, free-volume hole size decreases, but overall the volume fraction increases. The hole size distribution in dry polymer is seen to be distinctly different from hydrated membranes. The narrow and symmetric distribution in hydrated membrane as compared to dry membrane is believed to be a consequence of crosslinking due to cluster formation. In alcohol-swollen membranes, on the other hand, not only are the free-volume size and fraction seen to be higher, the hole size distribution is seen to be broader compared to dry or hydrated membranes, indicating the effect of penetration of alcohol into the hydrophobic backbone region. We have also examined our results vis-a-vis reported gas diffusion studies in Nafion in the framework of existing free-volume model. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 983-989, 1998
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
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