聚氧乙烯月桂醚在含醇的非水体系中的热力学性质的微量量热法研究

对于非离子表面活性剂聚氧乙烯月桂醚(Brij-35)/N,N-二甲基甲酰胺(DMF)/长链醇(庚醇,辛醇,壬醇,癸醇)体系,利用滴定微量量热仪测定了胶束形成过程的热功率-时间曲线.根据热力学理论,测定了临界胶束浓度和胶束形成热(ΔHmθ),计算了热力学函数(ΔGmθ和ΔSmθ).讨论了温度、醇中的碳原子数、醇的浓度与临界胶束浓度和热力学函数之间的关系.结果表明:聚氧乙烯月桂醚(Brij-35)/DMF/长链醇体系:(1)在含有相同浓度的各种醇的体系中,ΔHmθ和ΔSmθ的值随着温度的升高而增大;CMC,ΔGmθ的值随着温度的升高而降低;(2)在相同温度及相同浓度的醇体系中,CMC,ΔHmθ,ΔGmθ和ΔSmθ的值都随着醇中碳原子数的增加而降低;(3)在相同温度及相同醇的体系中,CMC,ΔHmθ,ΔSmθ和ΔGmθ的值随着醇的浓度的增加都减小.

Microcalorimetric studies on the thermodynamic property of polyoxyethylene lauryl ether in alcohol non-aqueous system

The power-time curves of the micelle formation process are determined for non-ionic surfactant polyoxyethylene lauryl ether （Brij-35） in the DMF/long-chain alcohol systems by titration microcalorimetry.From the power-time curves,the critical micelle concentration （CMC） and thermodynamic function （ΔHmθ、ΔGmθ、ΔSmθ） are obtained.For this system,the relationships between the temperature,the alcohol carbon number,the alcohol concentration and CMC,thermodynamic functions are discussed.It could be concluded as follows：（1） For polyoxyethylene lauryl ether （Brij-35） in the DMF/long-chain alcohol system,these ΔHmθ,ΔSmθ increased with the increment of the temperature while these CMC and ΔGmθ decreased with the increment of the temperature at the same carbon number of the alcohol,and the same concentration of the alcohol.（2） For polyoxyethylene lauryl ether （Brij-35） in the DMF/long-chain alcohol system,these CMC,ΔHmθ,ΔSmθ and ΔGmθ decreased with the increment of the carbon number of the alcohol,at the same concentration of the alcohol and the same temperature.（3） For polyoxyethylene lauryl ether （Brij-35） in the DMF /long-chain alcohol system,these CMC,ΔHmθ,ΔSmθ and ΔGmθ decreased with the increment of the concentration of the alcohol,at the same carbon number of the alcohol and the same temperature.