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Homogeneous length scale of shear-induced multilamellar vesicles studied by diffusion NMR.

Åslund, Ingrid LU ; Medronho, Bruno LU ; Topgaard, Daniel LU ; Söderman, Olle LU and Schmidt, Claudia (2011) In Journal of Magnetic Resonance 209. p.291-299
Abstract
A recently developed protocol for pulsed gradient spin echo (PGSE) NMR is applied for the size determination of multilamellar vesicles (MLVs). By monitoring the self-diffusion behavior of water, the technique yields an estimate of the homogeneous length scale λ(hom), i.e. the maximum length scale at which there is local structural heterogeneity in a globally homogeneous material. A cross-over between local non-Gaussian to global Gaussian diffusion is observed by varying the experimentally defined length- and time-scales. Occasional observation of a weak Bragg peak in the PGSE signal attenuation curves permits the direct estimation of the MLV radius in favorable cases, thus yielding the constant of proportionality between λ(hom) and radius.... (More)
A recently developed protocol for pulsed gradient spin echo (PGSE) NMR is applied for the size determination of multilamellar vesicles (MLVs). By monitoring the self-diffusion behavior of water, the technique yields an estimate of the homogeneous length scale λ(hom), i.e. the maximum length scale at which there is local structural heterogeneity in a globally homogeneous material. A cross-over between local non-Gaussian to global Gaussian diffusion is observed by varying the experimentally defined length- and time-scales. Occasional observation of a weak Bragg peak in the PGSE signal attenuation curves permits the direct estimation of the MLV radius in favorable cases, thus yielding the constant of proportionality between λ(hom) and radius. The microstructural origin of the Bragg peak is verified through Brownian dynamics simulations and a theoretical analysis based on the center-of-mass diffusion propagator. λ(hom) is decreasing with increasing shear rate in agreement with theoretical expectations and results from (2)H NMR lineshape analysis. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Journal of Magnetic Resonance
volume
209
pages
291 - 299
publisher
Elsevier
external identifiers
  • wos:000289270900024
  • pmid:21349752
  • scopus:79953196787
ISSN
1096-0856
DOI
10.1016/j.jmr.2011.01.024
language
English
LU publication?
yes
id
498ed6a1-5272-4477-ac99-0c54fedac61d (old id 1831370)
date added to LUP
2011-03-03 18:28:13
date last changed
2017-01-01 06:10:52
@article{498ed6a1-5272-4477-ac99-0c54fedac61d,
  abstract     = {A recently developed protocol for pulsed gradient spin echo (PGSE) NMR is applied for the size determination of multilamellar vesicles (MLVs). By monitoring the self-diffusion behavior of water, the technique yields an estimate of the homogeneous length scale λ(hom), i.e. the maximum length scale at which there is local structural heterogeneity in a globally homogeneous material. A cross-over between local non-Gaussian to global Gaussian diffusion is observed by varying the experimentally defined length- and time-scales. Occasional observation of a weak Bragg peak in the PGSE signal attenuation curves permits the direct estimation of the MLV radius in favorable cases, thus yielding the constant of proportionality between λ(hom) and radius. The microstructural origin of the Bragg peak is verified through Brownian dynamics simulations and a theoretical analysis based on the center-of-mass diffusion propagator. λ(hom) is decreasing with increasing shear rate in agreement with theoretical expectations and results from (2)H NMR lineshape analysis.},
  author       = {Åslund, Ingrid and Medronho, Bruno and Topgaard, Daniel and Söderman, Olle and Schmidt, Claudia},
  issn         = {1096-0856},
  language     = {eng},
  pages        = {291--299},
  publisher    = {Elsevier},
  series       = {Journal of Magnetic Resonance},
  title        = {Homogeneous length scale of shear-induced multilamellar vesicles studied by diffusion NMR.},
  url          = {http://dx.doi.org/10.1016/j.jmr.2011.01.024},
  volume       = {209},
  year         = {2011},
}