界面活性剤の製剤への応用研究 (第12報)

非イオン性界面活性剤による乳化系の転相温度に関する研究 (1) 電気抵抗-温度曲線と活性剤のHLB

抄録

Aspect of phase inversion of an emulsified system of nonionic surfactant by temperature variation was examined by measuring electric resistance. For this purpose, some modifications were made on the apparatus reported previously (Fig. 1). Characteristic electric resistance-temperature curve (Fig. 2) is obtained from the values of electric resistance of the system corresponding to the temperature variation. The system undergoes phase inversion from O/W type to W/O type with the rise in temperature and the values of its electric resistance show gentle decrease (S₁°) at first, then increase rapidly to the peak (G°), decrease again (S₂°), and rapidly increase again. These results showed that the Winsor theory can be applied to the emulsified system of nonionic surfactant, as in the case of the solubilized system.
It was also clarified that a linear relationship is established between the temperature of phase inversion and HLB value of nonionic surfactant in the emulsified system (Fig. 4). The HLB value of nonionic surfactant was shown to be easily measured from the measurement of electric resistance-temperature curve.