Study of the structure of water/aerosol OT/dodecane systems by time domain dielectric spectroscopy
Study of the structure of water/aerosol OT/dodecane systems by time domain dielectric spectroscopy
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DOI：
10.1021/j100248a038
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发表时间：
1985-06
期刊：
影响因子：
--
通讯作者：
J. Peyrelasse;C. Boned
中科院分区：
文献类型：
--
作者：
J. Peyrelasse;C. Boned
A microemulsion is a macroscopically monophasic, low-viscosity fluid system, resulting from the mutual “solubilization” of water and “oil”. Such mutual solubilization requires the addition of one or several surface-active agents, and, according to the composition and nature of the components, microemulsions of water in oil (w/o) or oil in water (o/w) can be obtained. When two sur-face-active agents are required, we find most often an alcohol together with an ionic type surfactant, but there are no experimental ways to know the distributionof oil and alcohol between the continuous phase, the disperse phase, and the interfacial layer, except along a demixing line. 1, 2 The validity conditions of the dilution method havebeen recently discussed. 1 23 Therefore, an-alyzing the results can often be difficult because the volume fraction of disperse matter is not generally known. If a single surface-active agent, such as sodium bis (2-ethylhexyl) sulfo-succinate (AOT) or sodium dipentyl sulfosuccinate (AY) is used, there is no more problem about locating the alcohol. When the critical micellar concentration (cmc) is much inferior to the concentration used (for the AOT, the cmc in the solvent generally ranges between 10'3 and 10" 4 mol/dm3), it can be admitted that the whole surface-active agent is localized at the interface. If the oil penetration in the interfacial film is neglected, we can have a good evaluation of the disperse-matter volume fraction, 4-5 water and surfactant, since these types of systems behave as ideal so-lutions (the surface-active agents, oil and water volumes can be added6). Angel et al. 7 have recently underlined the interest of studying the three-component microemulsions and have agreed that studying four-or five-component systems (brine) leads to theoretical and experimental difficulties hindering progress in the understanding of the properties of such systems. For example, in previous works, we carried out a study8 on the dielectric properties of surface double active agent microemulsions (soap+ alcohol). In some cases, the dielectric increment is very
