Aggregation Behavior of Long-Chain N-Aryl lmidazolium Bromide in a Room Temperature Ionic Liquid

作者：Shi, Lijuan; Li, Na; Zheng, Liqiang^*

来源：Journal of Physical Chemistry C, 2011, 115(37): 18295-18301.

DOI：10.1021/jp206325d

• AQUEOUS-SOLUTIONS
• MICELLE FORMATION
• SELF-AGGREGATION
• MICELLIZATION
• ADSORPTION
• CATALYSIS

The aggregation behavior of long-chain N-aryl imidazolium ionic liquids (ILs), 1-(2,4,6-trimethylphenyl)-3-alkylimidazolium bromide [C(n)pim]Br (n = 10, 12, 14), was investigated in a room temperature IL, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim] [BF4]) by surface tension measurements. Freeze-fracture transmission electron microscopy (FF-TEM) and dynamic light scattering (DLS) measurements further verified that micelles are formed. A relatively lower critical micelle concentration (CMC) and smaller micelle size were observed compared with that of N-alkylimidazolium ILs [C(n)mim]Br. The main reason for this phenomenon is that the electrostatic repulsion between the head groups of [C(n)pim]Br is weakened due to the incorporation of the 2,4,6-trimethylphenyl group. The thermodynamic parameters of micelle formation of [C(n)pim]Br in [bmim][BF4] were estimated from the CMC values and their temperature dependence. The micelle formation process is enthalpy-driven in the investigated temperature range, similar to the case in water. The novel N-aryl imidazolium ILs present strong fluorescence properties in [bmim] [BF4], indicating their potential application in the field of photochemistry.

• 出版日期2011-9-22
• 单位山东师范大学; 山东大学