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Water self‐diffusion coefficient determination in an ion exchange membrane by optical measurement
Author(s) -
Zelsmann H. R.,
Pineri M.,
Thomas M.,
Escoubes M.
Publication year - 1990
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1990.070410726
Subject(s) - diffusion , permeation , analytical chemistry (journal) , ionic bonding , membrane , chemistry , partition coefficient , ion , materials science , thermodynamics , chromatography , organic chemistry , biochemistry , physics
The self‐diffusion coefficient of water in a perfluorinated ionic membrane has been measured for different water contents corresponding to water vapor pressures less than the saturated one. The isotope method usually employed in the liquid state was extended to vapors, which led us to an observation of three different isotopic species by quantitative far IR spectroscopy. Two measurement methods are presented permitting a determination of the time lag and hence of the diffusion coefficient. The slow variation of the diffusion coefficient with the water concentration, as well as the good agreement of the numerical results given by different methods (permeation‐sorption) are explained by the fact that no plasticization occurs. This result has been independently verified by other experiments.