Phase Behavior of Oleyl Oleate with Nonionic Surfactants

Abstract

Oleyl oleate (OE), a liquid wax ester, has been reported as a potential raw material for cosmetic and pharmaceutical uses but little is known about its phase behavior in ternary systems. Two types of nonionic surfactants were selected, namely, Tween‐60 (T60) and Span 20 (S20). Phase diagrams of OE/T60/water and OE/S20/water systems were constructed at 25.0±0.5°C. Ternary phase diagrams of OE/T60∶S20 (20∶80 and 60∶40)/water systems were then constructed at the same temperature. The ratios of 80∶20 and 60∶40 of T60∶S20 were selected due to different solubility points of the surfactants in water. The results showed that the oleyl oleate with mixed surfactants system, OE/T60∶S20 (20∶80 and 60∶40)/water, gave better performance than the individual surfactant systems. The high percent of T60 of 80∶20 in the T60∶S20 system contributes to enlargement of the isotropic region. In contrast, by increasing the percent of S20 of 60∶40 in T60∶S20 contributes to a larger liquid crystalline region.

Keywords:

• Oleyl oleate
• liquid wax ester
• nonionic surfactant
• phase behavior

Acknowledgment

This project was financed by a grant from IRPA Project, No. 01‐02‐04‐0000‐PR, Malaysia.