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Title
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Inverted micellar structure determination of zinc-di-iso-hexadecyl-sulfonate in isododecane by small angle X-ray scattering and vapour pressure lowering
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Author
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Abstract
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| Small-angle X-ray scattering (SAXS), high-precision density measurements, and vapor pressure lowering (VPL) yield information on the micellar state of the anionic surfactant ZAS (Zn(C16H33SO3)2) in isododecane. Strong evidence is found for a bimodal size distribution of the surfactant over some small aggregates (oligomers) at a concentration of 0.5-1.0 mmole/liter and larger inverted micelles. The latter display a narrow size distribution around the average aggregation number, 17, which is rather temperature and concentration independent. The inverted micelles can be described as network structures with a diffuse transition region of 5A˚between the polar core and apolar collar. The low electron density in the polar core is probably due to the presence of solvent molecules and/or apolar surfactant tails even in its center. Convincing evidence is found for an aspherical shape of the micellar core. Two geometrical forms are proposed, either an elongated cylinder (h = 32A˚, r = 8.5A˚) or a disklike particle (h = 10A˚, r = 15A˚). |
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Language
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English
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Source (journal)
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Journal of colloid and interface science. - New York, N.Y., 1966, currens
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Publication
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New York, N.Y.
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1981
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ISSN
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0021-9797
[print]
1095-7103
[online]
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DOI
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10.1016/0021-9797(81)90416-1
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Volume/pages
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81
:2
(1981)
, p. 341-353
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ISI
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A1981LU66600006
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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