Formation and structure of liquid crystal in lecithin-water-oleic acid system were studied. It was found that different from the lecithin-water system, there are two types of llquid crystal present. The lamellar liquid crystal was formed at lower content of oleic acid, the values of interlayer spacing are larger tha-n the values in the corresponding liquid crystal without oleic acid. The inverse hexangonaJ liquid crysta1 was formed at higher content of oleic acid. In lecithin-water-oleic acid(containing 15 % cholesterol) system the phase behavior of liquid crystal is sidrilax to that in the lecithin-water-oleic acid system. The solubillzation rate of solid cholesterol in lammellar liquid crystal of lecithinwater-oleic acid system is more faster than that of lecithin-water system.
Miniemulsions were prepared using mixed emulsifiers comprising of fatty alcohols ROH (C5OH-C16OH) and ionic or noinonic surfactants in low concentration.As a cosurfactant, fatty alcohol served as an aid for decreasing the interfacial tension and increasing the lifetime of oil drops at the oil-water interface. The mixed emulsi fier R(EO)12-NP(EO)2-ROH(R=C5-C8) could spontaneously form O/W miniemulsion in kerosene-water system.
The variation of iinterfacial tension with temperature of two different systems, water-oil (liquid paraffin, C18H38, solution of solid paraffin)and silicone oil-vegetable oil was determined and the factors that influence the variation of the shape of the relation curves were examined.It is found that the presence of minute amount of surface active impurity was the main cause of the shape variation of the relation curves. The shape variation was eliminated by adsorptive agent.Therefore, it is important to insure purity of the experimental system in order to obtain reliable results on the study of thermocapillary flow caused by interfacial tension.
