Investigation of the phase behavior and an evaporation study of systems of lavender oil, water, Laureth 4, and Tween 80.

Natural essential lavender oil was obtained by steam distillation from the flowering plants. The phase behavior of a system of natural lavender oil, distilled water, and two stabilizers was investigated. The stabilizers that were used were tetraethyleneglycol lauryl ether (Laureth 4) and polyoxyethylen (20) sorbitan mono-oleate (Tween 80). For the first system (water, lavender oil, Laureth 4), the phase diagram shows an area of lamellar liquid crystal formed along the water-Laureth 4 axis. It solubilized up to 12% per weight of the lavender oil. The system formed one isotropic solution. The phase diagram for the second system (water, lavender oil, Tween 80) shows a small area of hexagonal liquid crystal that solubilized a maximum of only 3% of the lavender oil. The system shows two isotropic phases. Evaporation studies were done for the isotropic solutions in both systems. The results provided essential information about the behavior of lavender oil during evaporation.