Microstructure near the oil corner of a ternary microemulsion
- Lund Univ. (Sweden)
The microstructure in the oil-rich part of the microemulsion phase in the DDAB-water-dodecane system was investigated at 20 {degrees}C. Surfactant {sup 14}N NMR relaxation and water self-diffusion experiments were performed as a function of oil dilution for three different surfactant-to-water ratios, s/w. At high volume fractions, {Phi}{sup *}, of surfactant and water, the microstructure is biocontinuous. Upon dilution with oil, there is a gradual transition to a discrete particle structure. The average size of the particles decreases with dilution, to become spherical, with a radius dictated by s/w, at infinite dilution. At constant {Phi}, the particle size increases with increasing s/w. The volume fraction, {Phi}{sup *}, which marks the onset for the formation of a connected microstructure, decreases with increasing s/w. Outside the phase boundary at high water content, there is a concentrated and dilute microemulsion coexistence, with a critical point. This system does not have an oil dilution line of invariant spherical reverse micelles. 49 refs., 9 figs., 2 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 263616
- Journal Information:
- Journal of Physical Chemistry, Vol. 96, Issue 21; Other Information: PBD: 15 Oct 1992
- Country of Publication:
- United States
- Language:
- English
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