Anomalous diffusion of water in a hydrogel of sucrose and diepoxide monomers
| Autor: | H. F. Azurmendi, M. E. Ramia |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Stretched exponential function
Quantitative Biology::Biomolecules Molecular diffusion Field (physics) Chemistry Anomalous diffusion Diffusion Relaxation (NMR) Analytical chemistry General Physics and Astronomy Pulse sequence symbols.namesake Chemical physics symbols Physical and Theoretical Chemistry Debye |
| Zdroj: | The Journal of Chemical Physics. 114:9657-9662 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.1330214 |
| Popis: | This article is concerned with the study of the diffusion of water molecules in a hydrogel, obtained by controlled hydration of a cross-linked polymer of sucrose and diepoxide monomers. The diffusion measurements were performed by means of 1H(NMR) nuclear magnetic resonance techniques in the fringe field of a superconductor magnet with a field gradient G≃36.3 T m−1. This large field gradient and the stimulated echo pulse sequence allows to obtain time-dependent diffusion coefficients and to observe a non-Debye feature of the relaxation attenuation function. The behavior of the diffusion follows a stretched exponential function plus a Debye term, allowing the determination of different water domains. In the long time limit the diffusion follows a long tail Levy function, whose asymptotic limit is related to the fractal dimension of the underlying polymer structure. |
| Databáze: | OpenAIRE |
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