STUDY ON MISCIBILITY OF MOLECULES IN ORIENTED MOLECULAR ASSEMBLIES BY HIGH RESOLUTION CALORIMETER

1.用高精度等温滴定量热计精确测定了水与四甘醇单辛醚（C_8E_4）的混合焓随表面活性剂浓度和温度的变化关系。通过将所建立的热力学关系应用于所测得的混合焓，计算了单体和胶束的溶液微分焓和胶束形成焓。纯液体C_8E_4的溶解过程为热力学过程，胶束的形成过程为吸热过程。结果表明，水的偏摩尔焓可以提供一个洞察胶束状态下的水化。实验结果还表明，由量热法直接测得的胶束形成焓与由临界胶束浓度与温度的关系间接测得的胶束形成焓之间存在差异。2.将实验方法应用于混合表面活性剂体系混合焓的测定。此外，由于该量热计具有极高的分辨率，可用于直接测定界面形成焓和表面活性剂在界面上的吸附焓。

1.The enthalpy of mixing of water and tetraethylene glycol monooctyl ether (C8E4) was precisely measured as a function of concentration of surfactant and temperature by using the high accuracy isothermal titration calorimeter. The differential enthalpies of solution of monomer and micelle and the enthalpy of micelle formation were evaluated by applying the thermodynamic relations developed to the enthalpy of mixing measured. The dissolution of pure liquid C8E4 is exothernmic and the micelle formation is endothermic, respectively. It is shown that the partial molar enthalpy of water may afford an insight into the hydration in micellar state. It was also shown that there exists the difference in values between the enthalpy of micelle formation obtained directly from calorimetry and that indirectly from the temperature dependence of critical micelle concentration.2.The experimental method is now applied to the measurement of the enthalpy of mixing of mixed surfactant systems. Furthermore it was suggested that this calorimeter, because of its extremely high resolution, is applicable to measure directly the enthalpy of interface formation and adsorption of surfactant at the interface.