THEORY FOR INTERFACIAL-TENSION OF PARTIALLY MISCIBLE LIQUIDS

The aim of this work is to develop a mathematical relation between the interfacial tension (gamma-ab) of two partially miscible molecular liquids a and b with their pure liquid state surface tensions (gamma-a and gamma-b) with their respective vapours, using statistical mechanics. It is shown here that liquid-liquid interfacial tension can be mathematically correlated to the liquid-vapour surface tension by the following equation: gamma-ab = (DELTA-rho-a/DELTA-rho-a0)2-gamma-a + (DELTA-rho-b/DELTA-rho-b0)2-gamma-b - 2(sigma-aa sigma-bb/sigma-ab2)2(DELTA-rho-aDELTA-rho-h/DELTA-rho-a0 DELTA-rho-b0)(gamma-a gamma-b)1 2, where DELTA-rho-a and DELTA-rho-b are the density changes of the components a and b in the two partially miscible liquid phases and DELTA-rho-a0, DELTA-rho-b0 are the density changes of the pure liquids a and b with respect to their saturated vapours.