Aggregation Behavior Modulation of Ionic Liquid ۱-Dodecyl-۳-methylimidazolium Bromide by Sodium Salts in Aqueous Solutions

Ionic liquids (ILs) are organic salts that are liquids at temperatures below ۳۷۳.۱۵ K.They have received considerable attention as alternatives to the traditional organic solvents. Because of their interesting physical and chemical properties, such as negligible vapor pressure, unique permittivity, high thermal stability, good solvents for both organic and inorganic substances, high electrical conductivity, and wide electrochemical window, ILs have been widely used as reaction media, separation solvents, and novel electrolytes [۱,۲]. In recent years, ILs based on ۱-alkyl-۳-methylimidazolium cation [Cnmim]+ have received much attention and have been the most studied. An interesting aspect of such ILs is that the [Cnmim]+ cations possess inherent amphiphilic character when their alkyl group is a longer hydrocarbon chain. It has been shown that, ۱-dodecyl-۳-methylimidazolium bromide [C۱۲mim]Br behaves like a classical surfactant and forms aggregates in water with the critical micelle concentration (cmc) about ۹.۸ mM and then self-assembles to form lyotropic mesophases at higher concentrations [۳]. Literature survey reveals that aggregation behavior of ILs can also be tuned by the addition of some inorganic salts, but the related investigation is very limited. Therefore, a systematical study on the effect of the salt nature on the aggregation behavior of ILs is necessary from the viewpoint of fundamental and applied aspects.

کلیدواژه ها:

Ionic liquid ، Micelle ، Salt effect