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用微量量热法测定了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)在非水溶剂N,N-二甲基乙酰胺(DMA)中,分别加入长链醇(正庚醇、正辛醇、正壬醇、正癸醇)体系的热功率-时间曲线,由测得的曲线上的数据得到了临界胶束浓度(CMC)和形成热(ΔHm).根据热力学理论,计算了热力学函数(ΔGm,ΔSm),讨论了温度、醇中的碳原子数、醇的浓度与临界胶束浓度(CMC)和热力学函数之间的关系.结果表明:十六烷基三甲基溴化铵(CTAB)的DMA溶液,在含有相同浓度的各种醇的体系中,CMC,ΔHm和ΔSm的值随着温度的升高而增加;而ΔGm的值随着温度的升高而略有降低.在相同温度及相同浓度的醇体系中,CMC,ΔHm,ΔGm和ΔSm的值都随着醇中碳原子数的增加而降低.在相同温度及相同醇的体系中,CMC和ΔGm的值随着醇的浓度的增加而增加;而ΔHm和ΔSm的值随着醇的浓度的增加而减少.
The content of cationic surfactant cetyltrimethylammonium bromide (CTAB) in non-aqueous solvent N, N-dimethylacetamide (DMA) was determined by microcalorimetry. Alcohol, n-octanol, n-nonanol and n-decanol), the critical micelle concentration (CMC) and heat of formation (ΔHm) were obtained from the measured data on the curve. According to the thermodynamic theory, The thermodynamic functions (ΔGm, ΔSm) were calculated and the relationship between temperature, the number of carbon atoms in the alcohol, the concentration of alcohol and CMC and the thermodynamic function were discussed. The results showed that cetyltrimethyl In the DMA solution containing ammonium bromide (CTAB), the values of CMC, ΔHm and ΔSm increased with the increase of temperature in the system containing the same concentration of various alcohols; while the value of ΔGm slightly increased with the increase of temperature In the same temperature and the same concentration of alcohol system, CMC, ΔHm, ΔGm and ΔSm values ?? as the number of carbon atoms in the alcohol decreases in the same temperature and the same alcohol system, CMC and ΔGm The values increase with increasing alcohol concentration; while the values of ΔHm and ΔSm decrease with increasing alcohol concentration.