Aramaki Kenji, Tawa Kosuke, Shrestha Lok Kumar, Iwanaga Tetsuro, Kamada Miho
Graduate School of Environment and Information Sciences, Yokohama National University.
J Oleo Sci. 2013;62(10):803-8. doi: 10.5650/jos.62.803.
Phase behaviors in water/poly(oxyethylene) dodecyl ether (C₁₂EO(n), n = 4, 6, 8)/cetyl isooctanoate (CIO) systems were studied. In the C₁₂EO₆ and C₁₂EO₈ systems, self-assembled structures with positive curvatures, such as O/W microemulsions, and micellar cubic and hexagonal phases, were observed. A wider region of a lamellar liquid-crystalline phase, which included a narrow microemulsion region joined by a miscibility gap, was observed in the C₁₂EO₄ system. The structure of the microemulsion phase in the C₁₂EO₄ system was characterized by pulsed-field-gradient NMR (PFG-NMR) and small angle X-ray scattering (SAXS) techniques. PFG-NMR measurements indicated that the structure of the microemulsion was bicontinuous; both water and oil phases were continuous within the microemulsion. Pair-distance distribution function, p (r), and structure factors obtained by Generalized Indirect Fourier Transformation (GIFT) analysis of the SAXS data showed that the microemulsion domain sizes decreased with an increase in the oil content. The structure of the bicontinuous microemulsion was consistent with the results of a detergency test, in which the microemulsion samples were applied to lipstick dirt on an artificial skin plate. Detergency was observed to be better for the microemulsion at lower oil contents because of the larger oil domain size at these low concentrations.
研究了水/聚氧乙烯十二烷基醚（C₁₂EO(n)，n = 4、6、8）/十六烷基异辛酯（CIO）体系中的相行为。在C₁₂EO₆和C₁₂EO₈体系中，观察到具有正曲率的自组装结构，如O/W微乳液、胶束立方相和六方相。在C₁₂EO₄体系中，观察到一个更宽的层状液晶相区域，其中包括一个由混溶间隙连接的狭窄微乳液区域。采用脉冲场梯度核磁共振（PFG-NMR）和小角X射线散射（SAXS）技术对C₁₂EO₄体系中微乳液相的结构进行了表征。PFG-NMR测量表明，微乳液的结构是双连续的；在微乳液中，水相和油相都是连续的。通过对SAXS数据进行广义间接傅里叶变换（GIFT）分析得到的对距分布函数p（r）和结构因子表明，微乳液域尺寸随油含量的增加而减小。双连续微乳液的结构与去污力测试结果一致，在去污力测试中，将微乳液样品应用于人造皮肤板上的口红污垢。由于在这些低浓度下油域尺寸较大，因此观察到较低油含量的微乳液去污力更好。
