ABSTRACT
Solubilization of a synthetic perfume, IN, in the Wm and 11 phases is low. Upon further addition of IN, an excess-oil (0) phase separates from the phase boundaries of the single Wm and 11 regions. However, it was found that a large amount of IN (up to "-'80 wt %) can be incorporated into the 11 + 0 region in 0 /11 concentrated emulsions. Due to the large difference between the refractive index of pure water-C12E025 cubic phase (1.41 when the water-surfactant mass ratio is unity) and that of dispersed IN (1.52), the emulsions are not translucent. It is reported that no stable emulsion could be formed in the oil-rich (Wm + 0) region [42]. From Fig. 10 it is observed that the normal hexagonal and lamellar liquid crystals can solubilize a considerable amount of fi-ionone. But the samples in these liquid crystals regions are not so viscous and when they are kept in an open vessel the perfume molecules evaporate. On the other hand, the 0/11 emulsion not only contains a large amount of perfume but also is rather stable against the evaporation of perfume molecules, since in this emulsion system perfume droplets are covered by the extremely viscous I 1 phase. A large amount of other synthetic perfumes such as d-limonene can also be incorporated as a stable O/I1 highly concentrated emulsion.
