MODEL FRAGRANCE EMULSION SYSTEM 207 Phenethyl Alcohol L2 Water LLC Laureth 4 Figure 3. The phase diagram of water-laureth 4-phenethyl alcohol. L 2 = isotropic liquid (inverse micellar solution, W/O microemulsions) LLC = lameliar liquid crystal. Table II Diameters of Microemulsion Droplets in the Microemulsion Region From Light Scattering Laureth 4 (%) PEA (%) Water (%) Diameter (nm) 59.7 25.3 15 2.4 _+ 0.4 56.1 23.9 20 3.1 + 0.4 52.8 22.2 25 3.9 -+ 0.4 49.2 20.8 30 4.4 _+ 0.4 46 19 35 4.8 _+ 0.5 41.5 17.5 41 5.1 _+ 0.4 39.6 16.9 43.5 5.6 _+ 0.5 3 90 7 • 31 61 8 • 45 40 15 b 50 25 25 2.7 +_ 0.4 Scattering too weak. Some scattering, but cannot be resolved into reasonable size. aqueous solutions of phenethyl alcohol in the concentration range 2.2-1.5%, the equi- librium is with an oil liquid phase, a phenethyl alcohol/surfactant solution saturated with water. This oil phase does not contain any association structures for a surfactant/ (alcohol + surfactant) weight fraction less than 0.53 (Table II), while inverse micelies form in the solution for surfactant/alcohol ratios in the range 0.53-0.70 according to the

208 JOURNAL OF COSMETIC SCIENCE .- , Figure 4. Photographs of (A) emulsions 1-10 (from left to right), Table I and Figure 1, and (B) emulsions a-j (from left to right), Table I and Figure 2, after storage for two weeks.