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Measurement of diffusion coefficient and partition coefficient of sodium in nonionic polymer membranes
Author(s) -
Yasuda H.,
Lamaze C. E.
Publication year - 1969
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.1969.070131015
Subject(s) - partition coefficient , diffusion , polymer , fick's laws of diffusion , desorption , membrane , chemistry , thermodynamics , analytical chemistry (journal) , logarithm , chromatography , organic chemistry , adsorption , mathematics , physics , mathematical analysis , biochemistry
The difficulties involved in the measurement of the partition coefficient and diffusion coefficient of NaCl in hydrophilic polymer membranes are examined by the initial rate and late‐time analysis of desorption data for three nonionic polymer systems. The late‐time analysis, based on the plot of the logarithmic relative desorption versus time, was found to be useful when the diffusion is Fickian and the magnitude of D 2 / l 2 is small. Depending on the magnitude of D 2 / l 2 , an accurate measurement of k 2 and determination of D 2 cannot be achieved without correction for the effect of surface salt solution, impossible with late‐time analysis. The initial rate measurement was found more versatile for general non‐Fickian diffusion and it gave a means of correction of the errors involved in estimating the partition coefficient. In general, the diffusion of NaCl in hydrophilic polymers is not ideal Fickian and the discrepancy between the two analyses is appreciable.