6. Conclusion

The concept of HLD, based on thermodynamics and experimentally measurable, provides a methodology for unambiguous classification of surfactants and oils. It also makes it possible to design E /H, H /E or bicontinuous microemulsions to a given specification. It takes into account most of the parameters that formulators can use to adjust their formulas, and reveals their influence on the spontaneous curvature of the interfacial film.

Although HLD is not sufficient to model an entire water-oil-surfactant phase diagram, it is a powerful tool for predicting variations in phase behavior, for comparing various systems independently of their precise formulation, and for devising varied solutions to a given formulation problem. As we shall see in another article [J 2 157] dedicated to emulsions, the HLD concept is also an excellent tool for guiding the experimenter in the...