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Diffusion NMR for Determining the Homogeneous Length-Scale in Lamellar Phases.

Åslund, Ingrid LU ; Cabaleiro-Lago, Celia LU ; Söderman, Olle LU and Topgaard, Daniel LU (2008) In The Journal of Physical Chemistry Part B 112(10). p.2782-2794
Abstract
The size of the anisotropic domains in a lyotropic liquid crystal is estimated using a new protocol for diffusion NMR. Echo attenuation decays are recorded for different durations of the displacement-encoding gradient pulses, while keeping the effective diffusion time and the range of the wave vectors constant. Deviations between the sets of data appear if there are non-Gaussian diffusion processes occurring on the time-scale defined by the gradient pulse duration and the length-scale defined by the wave vector. The homogeneous length-scale is defined as the minimum length-scale for which the diffusion appears to be Gaussian. Simulations are performed to show that spatial variation of the director orientation in an otherwise homogeneous... (More)
The size of the anisotropic domains in a lyotropic liquid crystal is estimated using a new protocol for diffusion NMR. Echo attenuation decays are recorded for different durations of the displacement-encoding gradient pulses, while keeping the effective diffusion time and the range of the wave vectors constant. Deviations between the sets of data appear if there are non-Gaussian diffusion processes occurring on the time-scale defined by the gradient pulse duration and the length-scale defined by the wave vector. The homogeneous length-scale is defined as the minimum length-scale for which the diffusion appears to be Gaussian. Simulations are performed to show that spatial variation of the director orientation in an otherwise homogeneous system is sufficient to induce non-Gaussian diffusion. The method is demonstrated by numerical solutions of the Bloch-Torrey equation and experiments on a range of lamellar liquid crystals with different domain sizes. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
112
issue
10
pages
2782 - 2794
publisher
The American Chemical Society
external identifiers
  • pmid:18271569
  • wos:000253784700007
  • scopus:42449120153
ISSN
1520-5207
DOI
10.1021/jp076174l
language
English
LU publication?
yes
id
33347250-47fb-4676-b1a8-5f89267c77db (old id 1041986)
date added to LUP
2008-03-25 13:37:38
date last changed
2017-04-23 04:09:20
@article{33347250-47fb-4676-b1a8-5f89267c77db,
  abstract     = {The size of the anisotropic domains in a lyotropic liquid crystal is estimated using a new protocol for diffusion NMR. Echo attenuation decays are recorded for different durations of the displacement-encoding gradient pulses, while keeping the effective diffusion time and the range of the wave vectors constant. Deviations between the sets of data appear if there are non-Gaussian diffusion processes occurring on the time-scale defined by the gradient pulse duration and the length-scale defined by the wave vector. The homogeneous length-scale is defined as the minimum length-scale for which the diffusion appears to be Gaussian. Simulations are performed to show that spatial variation of the director orientation in an otherwise homogeneous system is sufficient to induce non-Gaussian diffusion. The method is demonstrated by numerical solutions of the Bloch-Torrey equation and experiments on a range of lamellar liquid crystals with different domain sizes.},
  author       = {Åslund, Ingrid and Cabaleiro-Lago, Celia and Söderman, Olle and Topgaard, Daniel},
  issn         = {1520-5207},
  language     = {eng},
  number       = {10},
  pages        = {2782--2794},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Diffusion NMR for Determining the Homogeneous Length-Scale in Lamellar Phases.},
  url          = {http://dx.doi.org/10.1021/jp076174l},
  volume       = {112},
  year         = {2008},
}