title: Aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in aqueous solution: effect of ionic liquids with aromatic anions.
abstract: The effects of ionic liquids (ILs), 1-butyl-3-methylimidazolium methylsulfonate (bmimMsa), 1-butyl-3-methylimidazolium benzenesulfonate (bmimBsa), and 1-butyl-3-methylimidazolium 2-naphthalenesulfonate (bmimNsa), on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide (C12mimBr) in aqueous solution were investigated by surface tension, dynamic light scattering measurements, and (1)H NMR spectroscopy. The ability to promote the surfactant aggregation is in the order bmimNsa > bmimBsa > bmimMsa. Nevertheless, only bmimNsa distinctly reduces both the CMC value and the surface tension at CMC. Due to the penetration of C10H7SO3(-)anions into the surfactant aggregate, bmimNsa is found to induce a phase transition from micelles to vesicles, whereas the other ILs only slightly increase the sizes of micelles. The combined effect of intermolecular interactions, such as hydrophobic effect, electrostatic attractions, and π-π stacking interactions, is supposed to be responsible for this structural transformation, in which π-π stacking plays an important role.
authors: Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, P. R. China.
authors: Yingqiu
authors: Y
authors: Gu
authors: Lijuan
authors: L
authors: Shi
authors: Xiyuan
authors: X
authors: Cheng
authors: Fei
authors: F
authors: Lu
authors: Liqiang
authors: L
authors: Zheng
mesh_terms: D000838:Anions / Q000737:chemistry; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D015394:Molecular Structure; D010316:Particle Size; D012996:Solutions; D013500:Surface Tension; D014867:Water / Q000737:chemistry
chemical_list: C521425:1-dodecyl-3-methylimidazolium; D000838:Anions; D006841:Hydrocarbons, Aromatic; D007093:Imidazoles; D052578:Ionic Liquids; D012996:Solutions; D014867:Water