Homogeneous length scale of shear-induced multilamellar vesicles studied by diffusion NMR.
Författare
Summary, in English
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.
Avdelning/ar
Publiceringsår
2011
Språk
Engelska
Sidor
291-299
Publikation/Tidskrift/Serie
Journal of Magnetic Resonance
Volym
209
Dokumenttyp
Artikel i tidskrift
Förlag
Academic Press
Ämne
- Physical Chemistry
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1096-0856