Nuclear magnetic resonance studies of water self-diffusion in porous systems

Research output: ThesisDoctoral Thesis (compilation)

Abstract

Proton nuclear magnetic resonance (NMR) was used to study the self-diffusion of water in porous systems that respond to a change in water content in order to elucidate the porous structure and the properties of the confined water.

In the carbohydrate systems cellulose fibers and starch granules, water is free to move throughout the porous objects, albeit with a rate reduced from the value of the bulk liquid, The reduction is related to the tortuosity of the pore space filled by water. A decrease of water content leads to a contraction of the porous network and an increased tortuosity. The anisotropic arrangement of the structural elements leads to an anisotropic water diffusion which can be quantified using high-quality NMR self-diffusion data and an adequate model for data analysis. Experiments performed at temperatures below the bulk freezing point showed that nonfreezing water exists as object-spanning films with a thickness of at least a few molecular diameters. Cross relaxation between protons in liquid and solid domains was found to be crucial for the interpretation of the diffusion data.

A technique to extend the range of experimental time scales for diffusion was demonstrated on a concentrated water-in-oil emulsion. A numerical method to compare experimental frequency-domain and theoretical time-domain apparent diffusion coefficients was proposed.

The Fourier relation between the signal obtained with the NMR self-diffusion experiment and the structure of the pore occupied by water was utilized for a model system consisting of a single water film. Methods analogous to the interpretation of X-ray diffraction data was used for the retrieval of the pore shape from the experimental data.
Original languageEnglish
QualificationDoctor
Awarding Institution
  • Physical Chemistry
Supervisors/Advisors
  • [unknown], [unknown], Supervisor, External person
Award date2003 Feb 28
Publisher
Print ISBNs91-628-5525-5
Publication statusPublished - 2003

Bibliographical note

Defence details

Date: 2003-02-28
Time: 10:15
Place: Lecture Hall A, Center for Chemistry and Chemical Engineering, Lund

External reviewer(s)

Name: Kimmich, Rainer
Title: Prof
Affiliation: Sektion Kernresonanzspektroskopie, Ulm University, Germany

---


Article: I. Diffusion of water absorbed in cellulose fibers studied with 1H-NMRDaniel Topgaard and Olle SödermanLangmuir 2001, 17, 2694-2702

Article: II. Self-diffusion in two- and three-dimensional powders of anisotropic domains: An NMR study of the diffusion of water in cellulose and starchDaniel Topgaard and Olle SödermanJournal of Physical Chemistry B 2002, 106, 11887-11892

Article: III. Changes of cellulose fiber wall structure during drying investigated using NMR self-diffusion and relaxation experimentsDaniel Topgaard and Olle SödermanCellulose 2002, 9, 139-147

Article: IV. Self-diffusion of nonfreezing water in porous carbohydrate polymer systems studied with nuclear magnetic resonanceDaniel Topgaard and Olle SödermanBiophysical Journal 2002, 83, 3596-3606

Article: V. Restricted self-diffusion of water in a highly concentrated w/o emulsion studied using modulated gradient spin-echo NMRDaniel Topgaard, Carin Malmborg and Olle SödermanJournal of Magnetic Resonance 2002, 156, 195-201

Article: VI. Experimental determination of pore shape and size using q-space NMR microscopy in the long diffusion-time limitDaniel Topgaard and Olle SödermanMagnetic Resonance Imaging 2002, in press

Subject classification (UKÄ)

  • Physical Chemistry

Keywords

  • diffusion diffraction
  • nonfreezing
  • anisotropy
  • tortuosity
  • cross relaxation
  • emulsion
  • starch
  • cellulose
  • porous material
  • water
  • NMR
  • self-diffusion
  • Physical chemistry
  • Fysikalisk kemi

Fingerprint

Dive into the research topics of 'Nuclear magnetic resonance studies of water self-diffusion in porous systems'. Together they form a unique fingerprint.

Cite this