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Title: Structure of guar in solutions of H{sub 2}O and D{sub 2}O: An ultra-small-angle light-scattering study

Abstract

The authors examine the structure of guar as a function of concentration in both H{sub 2}O and D{sub 2}O using several different scattering techniques. The range of scattering vectors spans 5 decades (143 cm{sup {minus}1} < q < 10.3 x 10{sup 6} cm{sup {minus}1}), providing insight into the supramolecular and local organization of the chains. This allows direct characterization of the large-scale aggregate structure of the guar, which can be on the order of 100 {micro}m. The aggregates are most likely loosely interconnected with single chains and other aggregates, and the structure and organization are critical in determining solution viscoelastic properties. The solubility is poorer in D{sub 2}O as evidenced by larger aggregates, higher scattering intensities, a slightly higher fractal dimension, and a sublinear concentration dependence of the intensity. Aggregates were found in dilute neutral guar solutions as well as in cationic guar solutions (in H{sub 2}O), whether screened or unscreened. The presence of aggregates at all concentrations for neutral and charged guar indicates the difficulty in determining a molecular weight of the guar molecule.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Rhodia Inc., Cranbury, NJ (US)
Sponsoring Org.:
National Aeronautics and Space Administration; National Science Foundation (NSF); USDOE
OSTI Identifier:
20075916
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 104; Journal Issue: 18; Other Information: PBD: 11 May 2000; Journal ID: ISSN 1089-5647
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; POLYSACCHARIDES; LIGHT SCATTERING; MOLECULAR STRUCTURE; HEAVY WATER; WATER; SOLUTIONS

Citation Formats

Gittings, M.R., Cipelletti, L., Trappe, V., Weitz, D.A., In, M., and Marques, C. Structure of guar in solutions of H{sub 2}O and D{sub 2}O: An ultra-small-angle light-scattering study. United States: N. p., 2000. Web. doi:10.1021/jp9943833.
Gittings, M.R., Cipelletti, L., Trappe, V., Weitz, D.A., In, M., & Marques, C. Structure of guar in solutions of H{sub 2}O and D{sub 2}O: An ultra-small-angle light-scattering study. United States. doi:10.1021/jp9943833.
Gittings, M.R., Cipelletti, L., Trappe, V., Weitz, D.A., In, M., and Marques, C. Thu . "Structure of guar in solutions of H{sub 2}O and D{sub 2}O: An ultra-small-angle light-scattering study". United States. doi:10.1021/jp9943833.
@article{osti_20075916,
title = {Structure of guar in solutions of H{sub 2}O and D{sub 2}O: An ultra-small-angle light-scattering study},
author = {Gittings, M.R. and Cipelletti, L. and Trappe, V. and Weitz, D.A. and In, M. and Marques, C.},
abstractNote = {The authors examine the structure of guar as a function of concentration in both H{sub 2}O and D{sub 2}O using several different scattering techniques. The range of scattering vectors spans 5 decades (143 cm{sup {minus}1} < q < 10.3 x 10{sup 6} cm{sup {minus}1}), providing insight into the supramolecular and local organization of the chains. This allows direct characterization of the large-scale aggregate structure of the guar, which can be on the order of 100 {micro}m. The aggregates are most likely loosely interconnected with single chains and other aggregates, and the structure and organization are critical in determining solution viscoelastic properties. The solubility is poorer in D{sub 2}O as evidenced by larger aggregates, higher scattering intensities, a slightly higher fractal dimension, and a sublinear concentration dependence of the intensity. Aggregates were found in dilute neutral guar solutions as well as in cationic guar solutions (in H{sub 2}O), whether screened or unscreened. The presence of aggregates at all concentrations for neutral and charged guar indicates the difficulty in determining a molecular weight of the guar molecule.},
doi = {10.1021/jp9943833},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
issn = {1089-5647},
number = 18,
volume = 104,
place = {United States},
year = {2000},
month = {5}
}