论文部分内容阅读
Mixing properties of the surface active ionic liquid1-tetradecyl-3-methylimidazolium bromide(C14mimBr)and the Gemini surfactant N,N-bis(dimethyldodecyl)-1,2-ethanediammonium dibromide(12-2-12)in water and in ethylammonium nitrate(EAN)were studied by surface tensiometry.The CMC values determined for the mixed surfactants in EAN werefound to be much larger than those in water,showing less ability of EAN in supporting self-aggregation of surfactants due to the high solubility of hydrophobic tailsof the surfactants in EAN resulted from its nonpolar nanostructure.The properties at the air/solvent interface like surface pressure at the CMC,the maximum surface excess,and the minimum surface area per molecule were determined and found to be different in water and in EAN mainly due to the strong electrostatic screening in EAN.The non-ideal mixing behaviors observed at the air/solvent interfaces and in the mixed micelles both in water and in EAN were analyzed to get the interaction parameters.The experimental results indicated that the synergisms existed in surface tension reduction efficiency and in surface tension reduction effectiveness for the mixed surfactants in water while the synergism in mixed micelle formation existedin EAN.The standard Gibbs free energy of micellization(△G 0m),the standard Gibbs free energy of adsorption(△G 0ads),and the excess Gibbs energy of mixed micelles(△G E)were determined and found to be negative.The comparisons of these thermodynamic properties in water and in EAN showed that both adsorption and micellization were less favorable in EAN,however,the mixed micelles were more stable in EAN.