title: Organic solvents induce the formation of oil-in-ionic liquid microemulsion aggregations.
abstract: The role of four organic solvents in the formation process of 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) based ionic liquid (IL) microemulsions is investigated. The results showed that the addition of Triton X-100 remarkably decreased the conductivity of bmimBF4. The added organic solvents provided a strong apolar environment for the hydrophobic tails of Triton X-100 and caused the surfactant molecules to aggregate into the interfacial film of oil-in-bmimBF4 (O/IL) microemulsions. As a result, the conductivities of the solutions were initially increased because the insulative Triton X-100 molecules were assembled, which corresponded to increasing the concentration of continuous bmimBF4 solutions. The hydrophobic interaction between the dispersed organic solvents and the hydrophobic tails of Triton X-100 may be the driving force for the formation of O/IL microemulsions. The droplets of O/IL microemulsions were successively swollen by organic solvents, and a bicontinuous IL-containing microemulsion was observed by freeze-fracture transmission electron microscopy for the first time. The current study can help in further understanding the ILs-containing microemulsions and thereby improve microemulsion theory.
authors.affiliation: Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, Jinan 250100, China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Gao
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zhang
authors.forename: Liqiang
authors.initials: L
authors.lastname: Zheng
authors.forename: Xinwei
authors.initials: X
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Dong
authors.forename: Li
authors.initials: L
authors.lastname: Yu