The influence of solvent on nonaqueous lyotropic liquid crystalline phase formed by triethanolammonium oleate.

The geometry of a lyotropic lamellar liquid crystalline phase formed by triethanolamine (TEA) and oleic acid (OLA) with solubilized oligomers of polyethylene glycols and different types of oils was determined from small angle X-ray diffraction patterns. The region of stability of the lamellar liquid crystalline phase on addition of soluble glycols or oils was found to depend on the molar ratio of triethanolamine to oleic acid. A series of ethylene glycol oligomers, which were solubilized in the polar part of the structure, showed maximum solubilization at the OLA-TEA mole ratio of 1.6. The organic oils, on the other hand, which are solubilized into the hydrophobic part of the structure, exhibited maximum solubilization at the OLA-TEA mole ratio of 0.8.