物理化学学报2017，Vol.33Issue(4)：795-802,8.DOI:10.3866/PKU.WHXB201612202
含酯基Gemini表面活性剂在有机醇-水体系中的胶束热力学及聚集行为
Aggregation Properties and Thermodynamics of Micellization of Gemini Surfactants with Diester and Rigid Spacers in Organic Alcohol-Water Mixed Media
摘要
Abstract
The aggregation behavior and thermodynamics of micellization for three Gemini surfactants with diester and rigid spacers in pure water and 10％ (mass fraction) organic alcohol-water co-solvents (MA-WR,EG-WR and GL-WR) across a range of temperatures from 283.15 to 308.15 K were investigated by electrical conductivity measurements.The aggregation behavior parameters,including critical micelle concentration (cmc),degree of counter ion dissociation (α),and the thermodynamic parameters of micellization including standardGibbs energy (△G°m),Gibbs energy of transfer (△G°trans),Gibbs energy of micellization per alkyl tail (△G°tail),standard enthalpy (△H°m),and standard entropy (△S°m) were calculated and discussed.Gemini surfactants with longer hydrophobic chain length have a lower cmc value,which was found to increase with the increasing number of hydroxyl groups of the alcohol in the organic mixed solvent.The temperature dependence of the cmc value for the Gemini surfactants was U-shaped in all the investigated systems.The micellization process is spontaneous,is endothermic at temperatures below 293.15 K,and becomes exothermic at temperatures above 293.15 K.The micropolarity of the Gemini surfactants in pure water and organic alcohol-water co-solvents were evaluated by steady-state fluorescence spectroscopy.The results showed that the hydrophobicity of the microenvironment for Gemini surfactant solutions becomes stronger with the increasing chain length of the surfactants and the number of hydroxyl groups of the alcohol in the organic mixed solvents.The compensation between the enthalpy and entropy for micellization of all the three gemini surfactants were observed in all the studied mixed media.关键词
Gemini表面活性剂/电导法/醇-水混合溶液/热力学参数Key words
Gemini surfactants/Conductivity/Organic alcohol co-solvent/Thermodynamic property分类
化学化工引用本文复制引用
张婷,沈杰..含酯基Gemini表面活性剂在有机醇-水体系中的胶束热力学及聚集行为[J].物理化学学报,2017,33(4):795-802,8.基金项目
The project was supported by the Natural Science Foundation of Anhui Province,China (KJ2016A184) and Research Funds of Anhui Science and Technology University,China (AKZDXK2015A01).安徽省教育厅自然科学基金重点项目(KJ2016A184)和安徽科技学院重点学科项目(AKZDXK2015A01)资助 （KJ2016A184）
