Effect of surface-active additives on the temperature behavior of interfacial tension in water-n-hexane systems

The temperature dependence of interface tension in a water-n-hexane system without additives and after addition of stearic acid was experimentally studied at four different concentrations. A method for determining the excess surface chemical potential from experimental data on the temperature dependence of interfacial or surface tension is proposed for a diluted solution of surface-active impurity. The excess surface chemical potential of stearic acid at the interface of a water-n-hexane binary mixture is determined.