On the Effect of Temperature and Pressure on the Interfacial Tension Between Two Liquid Phases

For the thermodynamic treatment of a binary system with a miscibility gap one has to introduce two excess quantities, i.e., the excess entropy of the interface and the excess concentration of one of the components. These quantities may be evaluated from the dependence of the interfacial tension on temperature and pressure. In this paper the corresponding equations are derived and their application discussed for the system H2OCS2. It turns out that such measurements hardly allow any conclusions about the detailed structure of the interfacial layer.