Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan; Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan.
J Colloid Interface Sci. 2023 Jul;641:348-358. doi: 10.1016/j.jcis.2023.03.060. Epub 2023 Mar 15.
Bicontinuous microemulsions (BMEs) have attracted attention as unique heterogeneous mixture for electrochemistry. An interface between two immiscible electrolyte solutions (ITIES) is an electrochemical system that straddles the interface between a saline and an organic solvent with a lipophilic electrolyte. Although most BMEs have been reported with nonpolar oils, such as toluene and fatty acids, it should be possible to construct a sponge-like three-dimensionally expanded ITIES comprising a BME phase.
Dichloromethane (DCM)-water microemulsions stabilized by a surfactant were investigated in terms of the concentrations of co-surfactants and hydrophilic/lipophilic salts. A Winsor III microemulsion three-layer system, consisting of an upper saline phase, a middle BME phase, and a lower DCM phase, was prepared, and electrochemistry was conducted in each phase.
We found the conditions for ITIES-BME phases. Regardless of where the three electrodes were placed in the macroscopically heterogeneous three-layer system, electrochemistry was possible, as in a homogeneous electrolyte solution. This indicates that the anodic and cathodic reactions can be divided into two immiscible solution phases. A redox flow battery comprising a three-layer system with a BME as the middle phase was demonstrated, paving the way for applications such as electrolysis synthesis and secondary batteries.
双连续型微乳液（BME）作为独特的非均相混合物，已引起电化学领域的关注。两种互不相溶的电解质溶液（ITIES）之间的界面是一种电化学体系，跨越盐水和有机溶剂与亲脂性电解质之间的界面。尽管大多数 BME 都是用非极性油（如甲苯和脂肪酸）报告的，但应该有可能构建一个由 BME 相组成的海绵状三维扩展的ITIES。
研究了由表面活性剂稳定的二氯甲烷（DCM）-水微乳液，考察了助表面活性剂的浓度和亲水/亲脂盐的浓度。制备了由上层盐水相、中间 BME 相和下层 DCM 相组成的 Winsor III 微乳液三层体系，并在各相中进行了电化学实验。
我们找到了ITIES-BME 相的条件。无论三个电极在宏观上不均匀的三层体系中的位置如何，都可以进行电化学实验，就像在均相电解质溶液中一样。这表明阳极和阴极反应可以分为两种不混溶的溶液相。展示了一种包含 BME 作为中间相的三层体系的氧化还原液流电池，为电解合成和二次电池等应用铺平了道路。
