Mixtures of water, octane and 1-octanol with 1-tetradecyl-3-methylimidazolium chloride (C₁₄MIM·Cl), often referred to as a surface active ionic liquid (SAIL), form water-in-oil microemulsions that have potential application as extraction media for various metal ions. Here, we present a structural study by small-angle neutron scattering (SANS) of dense microemulsions formed by surfactant-rich mixtures of these four compounds to understand how the SAIL can be used to tune the structures and properties of the microemulsions. The SANS experiments revealed that the microemulsions formed are composed of two phases, a water-in-oil microemulsion and a bicontinuous microemulsion, which becomes the dominant phase at high surfactant concentration. In this concentration regime, the surfactant film becomes more rigid, having a higher bending modulus that results from the parallel stacking of the imidazolium ring of the SAIL. At lower surfactant concentrations, the molecular packing of the SAIL does not change with the water content of the microemulsion. The results presented here correlate well with previously observed changes in the interaction between the IL cation and metal ions (Y. Tong, L. Han and Y. Yang, Ind. Eng. Chem. Res., 2012, 51, 16438–16443), while the capacity of the microemulsion system for water remains high enough for using the system as an extraction medium.

中文翻译：

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离子液体形成的致密微乳体系的小角中子散射研究

水，辛烷和1-辛醇与1-十四烷基-3-甲基咪唑鎓氯化物（C ₁₄通常被称为表面活性离子液体（SAIL）的MIM·Cl）形成油包水型微乳液，具有潜在的用途，可作为各种金属离子的萃取介质。在这里，我们通过小角度中子散射（SANS）对这四种化合物的富含表面活性剂的混合物形成的致密微乳状液进行结构研究，以了解如何使用SAIL来调节微乳状液的结构和性质。SANS实验表明，形成的微乳液由两相组成，即油包水微乳液和双连续微乳液，在高表面活性剂浓度下成为主导相。在这种浓缩方式下，表面活性剂膜变得更硬，具有更高的弯曲模量，这是由于SAIL的咪唑环平行堆叠而产生的。在较低的表面活性剂浓度下，SAIL的分子堆积不会随微乳液的含水量而变化。本文介绍的结果与先前观察到的IL阳离子与金属离子之间相互作用的变化具有很好的相关性（Y. Tong，L。Han和Y. Yang，工业工程师 化学 Res。，2012，51，16438-16443），而对水的微乳液体系的能力仍然使用该系统作为提取介质足够高的。