Inverse micellar solubility areas

The inverse micellar solubility areas in systems of water, surfactants and a third amphiphilic substance frequently are of a shape according to Fig. l. iZ/ Such shapes are also found in W/0 microemulsions —when water solubility is plotted against cosurfactant/surfactant fraction. 

Figure I. The solubility area of water in a hydrocarbon (CeH,) perUa(ethylene gly-c< ) dodecyl ether (C,t[EO]s) solution at 30°C. Key IM, inverse micellar solution.

These inverse micelles will solubilize electrolytes in their aqueous core but the presence of the electrolytes also will influence the stability of the inverse micelle. A change in the stability of the inverse micelle will be reflected in modifications of the solubility region of the inverse micellar solution. This chapter will relate the changes in solubility areas from addition of electrolytes to the water to the structure of inverse micelles and other association complexes in the pentanol solution. 

The ultrasonification process is connected with the rapidly increased oil-water interfacial area as well as the significant re-organization of the droplet clusters or droplet surface layer. This may lead to the formation of additional water-oil interface (inverse micelles) and, thereby, decrease the amount of free emulsifier in the reaction medium. This is supposed to be more pronounced in the systems with non-ionic emulsifier. Furthermore, the high-oil solubility of non-ionic emulsifier and the continuous release of non-micellar emulsifier during polymerization influence the particle nucleation and polymerization kinetics by a complex way. For example, the hairy particles stabilized by non-ionic emulsifier (electrosteric or steric stabilization) enhance the barrier for entering radicals and differ from the polymer particles stabilized by ionic emulsifier. The hydro-phobic non-ionic emulsifier (at high temperature) can act as hydrophobe. 

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