Ultralow interfacial tensions in water-n-alkane-surfactant systems
Ultralow interfacial tensions in water-n-alkane-surfactant systems
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DOI：
10.1063/1.473916
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发表时间：
1997-05-22
影响因子：
4.4
通讯作者：
Strey, R
中科院分区：
文献类型：
--
作者：
Sottmann, T;Strey, R
测定了水、正构烷烃和非离子烷基聚乙二醇醚表面活性剂(CiEj)三元体系在微乳液存在下富水相和富油相之间的界面张力。研究发现，界面张力曲线的最小值与众所周知的相反转现象有关，它与油和表面活性剂的化学性质有关，而且是敏感的，但又是系统的。具体地说，当烷烃的碳数k减少6或氧乙烯基数j减少3，或表面活性剂尾部的碳原子数i增加2时，界面张力的最小值(Ab)减小1个数量级。界面张力的数值随温度的函数与先前提出的经验描述一起给出[R.Strey，Colloid and Polmer Sci]。272,1005(1994)]。通过分析，根据弯曲能，可以得到弯曲常数和鞍展常数的估计。界面张力曲线的相似形状允许所有19个体系的数据叠加，以支持最近导出的标度关系[S.Leitao，A.M.Somoza，M.M.Telo da Gama，T.Sottmann，和R.Strey，J.Chem]。太棒了。105,2875(1996)]。此外，在近临界体系中，临界振幅比R=sigma(0)xi(0)=0.37kT的数值与乘积(Ab)xi(-2)=0.44(+/-0.10)kT的数值非常吻合，这里是双连续微乳液的最大长度尺度。(C)1997年美国物理研究所。
The interfacial tensions between water- and oil-rich phases in the presence of microemulsions have been measured for ternary systems of water, n-alkanes, and nonionic alkylpolyglycolether surfactants (CiEj). It is found that the minimum of the interfacial tension curve, which is observed for each system in conjunction with the well-known phenomenon of phase inversion, depends sensitively, but systematically, on the chemical nature of the oil and the surfactant. Specifically, the minimum value of the interfacial tension (ab) decreases by 1 order of magnitude on decreasing either the carbon number of the alkane k by 6, or the number of oxyethylene groups j by 3, or by increasing the number of carbon atoms in the surfactant tail i by 2. The numerical values of the interfacial tensions as a function of temperature an presented along with an empirical description previously suggested [R. Strey, Colloid and Polymer Sci. 272, 1005 (1994)]. From the analysis, in terms of bending energy one obtains estimates for the bending and saddle-splay constants. The similar shape of the interfacial tension curves permits a superposition of the data for all 19 systems in support of a scaling relation recently derived [S. Leitao, A. M. Somoza, M. M. Telo da Gama, T. Sottmann, and R. Strey, J. Chem. Phys. 105, 2875 (1996)]. Furthermore, we note a striking coincidence of the numerical values of critical amplitude ratio R=sigma(0) xi(0)=0.37 kT in near-critical systems and the product (ab)xi(-2)=0.44(+/-0.10) kT where is the maximum length scale in the bicontinuous microemulsions. (C) 1997 American Institute of Physics.