X-ray scattering studies of the structure of aqueous hydroxy-propylcellulose solutions
β Scribed by G. D. Wignall; B. K. Annis; R. Triolo
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 413 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0887-6266
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β¦ Synopsis
Abstract
Xβray diffraction studies have been undertaken on aqueous solutions of hydroxy propylcellulose (HPC) over a wide range of the scattering vector Q. The experiments revealed only modest differences in local structure on a distance scale ca. 5β300 Γ despite the fact that they covered concentrations generally interpreted as ranging from the isotropic (35.1 wt %) to the anisotropic liquid crystalline (LC) phase (53.5 wt %). Several models were used to interpret the smallβangle scattering data, and each gave similar structural parameters and extrapolated intensities (Q β 0) for both solutions. Peaks were observed with dβspacings ca. 12β17 Γ in both materials. Wideβangle xβray scattering (WAXS) showed slightly increased local order over a size range ca. 5β20 Γ for the anisotropic solution, and this is consistent with a greater intensity of the 13 Γ peak in this material. It is difficult to reconcile these findings with an interpretation of the LC state involving major differences with the isotropic phase and a high degree of orientational order extending over long length scales.
π SIMILAR VOLUMES
LiBr aqueous solutions were invest&ted by X-ray diffraction in order to study the strucrure of hydrated Br-ions. A simple model describing the coordination sound the ions only in terms of newest-neiabour intcnctions