Premium
NMR water self‐diffusion and relaxation studies on sodium polyacrylate solutions and gels in physiologic ionic solutions
Author(s) -
Bai Ruiliang,
Basser Peter J.,
Briber Robert M.,
Horkay Ferenc
Publication year - 2014
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.40001
Subject(s) - diffusion , polymer , relaxation (psychology) , chemistry , sodium polyacrylate , self diffusion , ionic bonding , sodium , polymer chemistry , analytical chemistry (journal) , thermodynamics , chromatography , organic chemistry , ion , psychology , social psychology , raw material , physics , self service , marketing , business
Water self‐diffusion coefficients and longitudinal relaxation rates in sodium polyacrylate solutions and gels were measured by NMR, as a function of polymer content and structure in a physiological concentration range of monovalent and divalent cations, Ca 2+ and Na + . Several physical models describing the self‐diffusion of the solvent were applied and compared. A free‐volume model was found to be in good agreement with the experimental results over a wide range of polymer concentrations. The longitudinal relaxation rate exhibited linear dependence on polymer concentration below a critical concentration and showed non‐linear behavior at higher concentrations. Both the water self‐diffusion and relaxation were less influenced by the polymer in the gel state than in the uncrosslinked polymer solutions. The effect of Na + on the mobility of water molecules was practically undetectable. In contrast, addition of Ca 2+ strongly increased the longitudinal relaxation rate while its effect on the self‐diffusion coefficient was much less pronounced. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131 , 40001.