Fourier transform-IR and 1 H NMR studies on the structure of water solubilized by reverse aggregates of calcium bis(2-ethylhexyl) sulfosuccinate in organic solvents

Autor: O. A. El Seoud, Luzia P. Novaki, Paulo Augusto Rodrigues Pires
Rok vydání: 2000
Předmět:
Zdroj: Colloid & Polymer Science. 278:143-149
ISSN: 1435-1536
0303-402X
DOI: 10.1007/s003960050024
Popis: The structure of water solubilized by reverse aggregates of calcium bis(2-ethylhexyl) sulfosuccinate in deuterobenzene and toluene has been probed by Fourier transform-IR and 1 H NMR spectroscopies. The ν OD band of solubilized HOD (4% D 2 O in H 2 O) has been recorded as a function of the [water]/[surfactant] molar ratio, W/S. Curve fitting of this band showed the presence of a main peak at 2550 ± 13 cm -1 and a small one at 2405 ± 15 cm -1 . As a function of increasing W/S, the frequency of the main peak decreases, its full width at half-height increases, and its area increases linearly. The 1 H NMR chemical shift of solubilized H 2 O-D 2 O mixtures at W/S = 18.1 has been measured as a function of the deuterium content of the aqueous nanodroplet. These data were used to calculate the so-called fractionation factor of the aggregate-solubilized water, the value of which was found to be unity. The results of both techniques show that reverse aggregate-solubilized water, although different from bulk water, does not seem to coexist in layers of different degrees of structure, as suggested, for example by the two-state water-solubilization model.
Databáze: OpenAIRE
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