Department of Chemistry, Aligarh Muslim University, Aligarh 202 002, India.
J Colloid Interface Sci. 2010 Feb 15;342(2):340-7. doi: 10.1016/j.jcis.2009.10.056. Epub 2009 Oct 27.
The micellization of gemini surfactant pentamethylene-1,5-bis(tetradecyldimethylammonium bromide) (14-5-14) has been investigated in water and water-organic solvent mixed media (organic solvents used: 1,4-dioxane (DO), dimethylformamide (DMF), ethylene glycol (EG)). The conductivity in water and in mixed media (water+organic solvent) as a function of surfactant concentration was measured at different temperatures and the data were used to find critical micelle concentration (cmc) and degree of counterion dissociation (alpha) of the micelle. From the study, it is observed that the micellization tendency of the surfactant decreases in the presence of organic solvents and the increase in the cmc values is comparatively less below 20% (v/v) of organic solvents showing the predominance of water character in the bulk phase at lower compositions of the organic solvents. Thermodynamic parameters were also obtained from the temperature dependence of the cmc values. The standard free energy of micellization was found to be negative in all the cases that became less negative with the increase in the cosolvent content.
双子表面活性剂五亚甲基-1,5-双（十四烷基二甲基溴化铵）（14-5-14）在水和水-有机溶剂混合介质中的胶束化行为已经得到研究（所用有机溶剂：1,4-二氧六环（DO）、二甲基甲酰胺（DMF）、乙二醇（EG））。在不同温度下测量了水和混合介质（水+有机溶剂）中表面活性剂浓度的电导率，并利用数据确定了胶束的临界胶束浓度（cmc）和反离子离解度（α）。研究表明，在有机溶剂存在下，表面活性剂的胶束化趋势降低，并且在有机溶剂含量低于 20%（v/v）时，cmc 值的增加相对较少，表明在较低有机溶剂组成下，主体相具有更多的水性质。还从 cmc 值的温度依赖性获得了热力学参数。在所有情况下，胶束化的标准自由能均为负值，并且随着共溶剂含量的增加，标准自由能变得不那么负。
