Synopsis

The partition behavior of homogeneous and Poisson distribution onionic surfactants in the oil-water system was studied in connection with the type of emulsion produced. The partition isotherms exhibited an abrupt change of slope at the critical micelle concentration. It was shown that the phase in which micelles are formed will be the continuous phase in the formation of emulsions. Moreover, the hydrophilic-lipophilic characteristics of homogeneous nonionic surfactants were found to be independent of surfactant concentration whereas those of inhomogeneous ones did change with concentration. For an inhomogeneous nonionic surfactant, which has a Poisson distribution of molecular weights, the proportions of each component extracted to each phase were determined by gas chromatography to elucidate the mechanism ofemulsifier blending. The deviations of HLB numbers of emulsifier blends from weight average were attributed to the changes in composition of the mixed micelles formed in the oil-water system with total emulsifier concentration and/or with mixing ratios of the constituent emulsifiers