Phase behavior and metastability in a nonionic surfactant-water-electrolyte system

Journal Article · Thu Sep 20 00:00:00 EDT 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100382a052· OSTI ID:6469859

Wilcoxon, J P ^[1]

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1. Sandia National Labs., Albuquerque, NM (USA)

The author uses static and dynamic light scattering to investigate the concentration fluctuations occurring in the single to binary phase transition of the two analogous systems C{sub 12}E{sub 5}/H{sub 2}O and C{sub 12}E{sub 6}/H{sub 2}O/NaCl (10 wt %). The effect of surfactant concentration and temperature on the osmotic compressibility, static correlation length, and diffusion coefficient is investigated. Both systems fall into the same universality class as simple binary fluids. For concentrations differing from the critical concentration, the suppression of critical fluctuations results in finite correlation lengths and compressibilities. Measurements at the critical concentration reveal a true divergence of these quantities with correlation lengths exceeding the instrumental resolution (i.e. > 5,000 {angstrom}). Measurements of the diffusion coefficient vs momentum transfer follow the predictions of simple mode-mode coupling theory for concentrations less than or equal to the critical concentration but Kawasaki mode-mode fluctuations are suppressed significantly above the critical concentration.

• OSTI ID: 6469859
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:19; ISSN JPCHA; ISSN 0022-3654
• Country of Publication: United States
• Language: English

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BINARY MIXTURES
CALCULATION METHODS
DISPERSIONS
ELECTROLYTES
HYDROGEN COMPOUNDS
LIGHT SCATTERING
MIXTURES
OXYGEN COMPOUNDS
PHASE STUDIES
SCATTERING
SURFACTANTS
WATER