Micelle and microemulsion properties of cesium di-dodecyl-dimethylsulfosuccinate, Cs-AOT
Cesium di-2-ethylsulfosuccinate (Cs-AOT) micelles in aqueous solutions and Cs-AOT/water/n-decane microemulsions were investigated, at 22 {plus{underscore}minus} 0.1 C, by small angle neutron scattering (SANS). The critical micelle concentration of Cs-AOT is {approximately}2mM, comparable to that of Na-AOT. However, their solution properties and micellar structures were found to be very different. The solubility of Na-AOT in water is approximately 1 wt %, and the micelles grow from spherical (at a concentration of about 0.1 wt %) to oblate objects with eccentricity equal to about 0.8 (at a concentration of 1 wt %), whereas Cs-AOT is largely soluble in water, over 30 wt %, and its micelles are disklike at 1 wt %. As the surfactant concentration increases, micelles may go through an L{sub 3} region, and enter the lamellar phase. Cs-AOT/water/n-decane microemulsions, with a [water]/[Cs-AOT] = 29.1, form isotropic L{sub 2} phases only at very low Cs-AOT + ater volume fractions (below 0.0165), whereas Na-AOT has a large L{sub 2} region. These differences are probably due to the degree of charge condensation near the AOT polar headgroups. A theoretical description is needed to better understand this behavior.
- Research Organization:
- Univ. of Florence (IT)
- Sponsoring Organization:
- National Institute of Standards and Technology; Department of Energy; Italian Center for Colloid and Surface Science
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 20013607
- Journal Information:
- Langmuir, Vol. 15, Issue 20; Other Information: PBD: 28 Sep 1999; ISSN 0743-7463
- Country of Publication:
- United States
- Language:
- English
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