CAJ | 학술논문

以表面张力法研究了系列烷基芳基磺酸盐在水溶液中胶束化的热力学性质,并考察了温度与分子结构对胶束化的影响.结果表明,烷基芳基磺酸盐在水溶液中胶束化是一个自发过程,主要来自熵驱动;随着温度升高,先有利于胶束化而后又不利于胶束化,且熵变对吉布斯自由能变的贡献有下降趋势,而焓变的贡献有增大趋势;胶束化存在焓-熵补偿现象,补偿温度T_c均在(306±2)K,基本不随烷基芳基磺酸盐的分子结构的改变而变化;随着芳环上短烷基链或长烷基链碳数的增加,胶束化能力和胶束的稳定性均提高,而随着芳环向长烷基链中间位置移动,胶束化能力和胶束的稳定性均下降.
이표면장역법연구료계렬완기방기광산염재수용액중효속화적열역학성질,병고찰료온도여분자결구대효속화적영향.결과표명,완기방기광산염재수용액중효속화시일개자발과정,주요래자적구동;수착온도승고,선유리우효속화이후우불리우효속화,차적변대길포사자유능변적공헌유하강추세,이함변적공헌유증대추세;효속화존재함-적보상현상,보상온도T_c균재(306±2)K,기본불수완기방기광산염적분자결구적개변이변화;수착방배상단완기련혹장완기련탄수적증가,효속화능력화효속적은정성균제고,이수착방배향장완기련중간위치이동,효속화능력화효속적은정성균하강.
We used a surface tension method to investigate the thermodynamic properties of micellization in aqueous solution for several alkyl aryl sulfonates that were synthesized in our laboratory. The influence of temperature and molecular structure on the micellization is discussed. Results show that the micellization of alkyl aryl sulfonates in aqueous solutions is spontaneous and entropy-driven. As the temperature rises, the micellization is easy initially but then becomes more difficult. The contribution of entropy change to the change in Gibbs free energy tends to decrease but the contribution of enthalpy change to the change in Gibbs free energy tends to increase. The micellization is enthalpy-entropy compensated. The compensation temperature (T_c) is found to be (306±2) K, which is independent of the molecular structure of the alkyl aryl sulfonates. The formation ability and the stability of the micelles increase when the carbon atoms of the short or long alkyl chains on the aromatic rings increase, but decrease as the aromatic rings shift from the edge to the middle of the long carbonic chains.