Transitions Winsor diagrams

Winsor diagram types are very useful for explaining most transitions in phase behavior that are found in practice. However, the real ternary diagrams are often more complex, and on the other hand, the ternary approximation is not always sufficient. A quaternary approach (at least) is often required to describe the characteristics of a given system. 

The first supercritical microemulsion model [43] was in good agreement with experimental data such as those of Figs. 6 and 7. The model also applies to the one-and two-phase reverse micelle systems of Sec. II. It was found that micelle-micelle interaction effects are dominant in reverse micelle systems where the water/oil ratio is small. However, in the Winsor microemulsion systems described in this section, which have a water/oil ratio near unity, the size of the reverse micelles in the oil phase is determined by natural curvature effects. Micelle-micelle interactions become important at phase transition points, as was observed experimentally in the AOT-brine-propane system [21,23]. The transition between the natural curvature and micelle-micelle interaction mechanisms can be understood in detail on a ternary phase diagram [43]. 

Experimemal evidence gathered by Winsor and scores of other researchers afterward have shown that as a field variable (one of the formulation variables or temperature) is changed as in Fig. 7, the phase behavior diagram exhibits a continuous transition from type I to type II passing through type HI, or vice versa, depending on the selected scan variable (11.22.25-27). 

In the previous case the phase behavior transition was produced by a change in the ratio S/A, i.e., in the amphiphilic mixture hydrophilicity. In the present one the phase behavior change is mainly due to the total concentration of amphiphile mixture, which drives a considerable hydrophilicity variation. These are two cases of quaternary systems in which a composition change produces a phase behavior change typical of the fonnulation effect in Winsor s diagrams. Such a... 

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