Phase behavior of a nonaqueous ternary microemulsion containing ethylammonium nitrate, TX-100, and cyclohexane

A nonaqueous ionic liquid (IL) microemulsion containing ethylammonium nitrate (EAN), the surfactant TX-100, and cyclohexane was prepared at room temperature, and phase behavior of this ternary system was investigated at 25 ± 0.1 °C. Electric conductivity measurements were performed to identify the microregions of the nonaqueous IL microemulsion. Based on percolation theory, an EAN-in-cyclohexane (IL/O), a bicontinuous, and a cyclohexane-in-EAN (O/IL) microregion were successfully identified using cyclohexane as the titration phase. Dynamic light scattering measurements were used to study the formation of the IL pools. UV–vis spectroscopy using methyl orange as probe material was employed to investigate the micropolarity of the system. The results indicate that the micropolarity of the IL/O microemulsion increases with the EAN content after the IL pools are formed. With this work, we expect to improve the basic understanding of nonaqueous microemulsions.