NMR water self-diffusion and relaxation studies on sodium polyacrylate solutions and gels in physiologic ionic solutions
Article first published online: 8 OCT 2013
Copyright © 2013 Wiley Periodicals, Inc.
Journal of Applied Polymer Science
Volume 131, Issue 6, March 15, 2014
How to Cite
2014), NMR water self-diffusion and relaxation studies on sodium polyacrylate solutions and gels in physiologic ionic solutions. J. Appl. Polym. Sci., 131, doi: 10.1002/app.40001, , and (
- Issue published online: 20 DEC 2013
- Article first published online: 8 OCT 2013
- Manuscript Accepted: 24 SEP 2013
- Manuscript Received: 15 JUL 2013
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, Ca2+ 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 Ca2+ 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.