The formation and structure of liquid crystal in Tween 80, Tween 85, Tween 85-Span 80 and H2O systems were studied. At room temperature, the results of low angle X-ray diffraction showed that hexagonal liquid crystal was formed in Tween 80-H2O system, whereas in Tween 85- H2O and Tween 80-Span 80 (7:3)-H2O systems lamellar liquid crystal was formed. In two lamellar crystal phases the thickness of amphiphilic layer was 66.8A and 68.0A respectively. The penetration of water in Tween 85 liquid crystal phase was higher than in Tween 80-Span 80 liquld crystal phase.
For preparing O/W miniemulsions containing soybean oil and silicone oil, three methods, phase inversion emulsification, D-phase emulsification, reformed D-phase emulsification were tested by using Brij92, 97, 98 and Tween 80, 85, 60, 20 and Span 80, 60 mixed surfactants. It was found that the O/W miniemulsions of soybean oil and silicone oil can not be formed by phase inversion emulsification method, but can be formed by the two other methods. The results of emulsification showed that if gel emulsion, in which fine oil droplets disperse in continuous phase with high surfactant content, appears during the emulsification process, the O/W miniemulsions can be formed by simply diluting with water.
