The Selection of Emulsifier in W/O Type Emulsions by HLB-Temperature (PIT) System

The dissolution state of polyoxyethylene (n) nonylphenylether-water-cyclohexane system was studied as a function of temperature. The phase inversion temperature (PIT) and the temperature range over which W/O type emulsions are stable were determined. As a result, the relation between the PIT and the oxyethylene chain length of emulsifiers which will give the stable W/O type emulsions was obtained, thereby an emulsifier which will yield stable emulsion at a given temperature can be selected. Emulsions are most stable, if we select emulsifiers whose oxyethylene chain length is shorter by about two as compared with the emulsifier whose PIT (HLB-temperature) is equal to an experimental temperature. Thus, the procedures for the emulsifier selection of W/O type became clear by HLB-temperature method.