434 JOURNAL OF COSMETIC SCIENCE Fragrance Water Surfactant Figure 3. Phase diagram of surfacranr/water/syntheric fragrance and the different evaporation pathways. chain length creates a disorder of the end part of the hydrocarbon. Limonene and linalool fill this disorder, and so the LLC is clearly present in their phase behavior (10,12,15). This does not happen for phenethyl alcohol (11). For this contribution of the whole lavender oil, a similar condition takes place, as the oil contains a variety of many hydrocarbons, and so its phase diagram contains LC. The structure of LLC allows the presence of both the hydrocarbons and the polar components to fit, while in the HLC, the structure does not allow for that. On the other hand, the phase diagram consists of typical L 2 and L• and all the emulsion areas (Figures 1, 2). The results show how fragrance ingredients are solubilized in surfactant solution (L2) , and such a system serves as a fragrance reservoir. The results of comparing the two surfactants and different compositions were to see the role of the structure and the polarity of the surfactant in the solubility of the multi- compound fragrance. The relative hydrophilicity of Laureth 4 and Tween 80 allows the LC region to extend further and to hold many similar hydrophilic compounds inside it. With the Laureth 4 system, the LLC region is larger due to a linear system of LLC that allows more fragrance to get in (Figure 4). With the Tween system, the HLC is reduced, compared to the other system with lavender oil, which indicates the instability of a hexagonal liquid crystal structure that contains fragrance compounds (18). A room-temperature evaporation study was performed for two selected samples on a small scale (glass slides). For the first system (water/Tween 80/lavender oil), the com- positions of selected samples are shown in Table I: The first sample was a one-phase microemulsion (sample S•) with a composition of 83.5% water, 1.3% lavender oil, and 15.2% Tween 80 by weight. The second sample was a two-phase emulsion (sample S2) with a composition of 64% water, 29.5% lavender oil, and 6.5% Tween 80 by weight.

LAVENDER OIL/WATER/STABILIZER SYSTEMS 435 d B A Figure 4. The structure of the lameliar liquid crystal (LLC) may be described by three layers: (A) water plus polar groups, (B) hydrocarbon polyethylene chains, and (C) hydrocarbon methyl groups. The different evaporation paths are shown in Figure 5. Water is the fastest in evaporation at room temperature when it is alone, as it evaporates 100% in about 60 minutes. The pure lavender oil is slower, as it takes two hours to reduce the total weight to 80%. The evaporation of the two samples took almost seven hours to reduce the weight of S• to 10%, while the S 2 sample needed six hours to reduce to 40%, and it stayed almost constant at this ratio for both samples. Table I The Percent Composition for Samples S• and S 2 for the Evaporation Study of the Water/Lavender Oil/Tween 80 System Sample % Water % Lavender oil % Tween 80 Number of phases S1 83.5 1.3 15.2 1 S 2 64.0 29.5 6.5 2