INTERFACIAL-TENSION AND INTERFACE PHASE-TRANSITIONS IN 2-PHASE WATER-LONG-CHAINED ALCOHOLS SYSTEMS

The interfacial tensions of six two-phase systems of water-normal alcohols (number of carbon atoms from 10 to 15) were measured in function of temperature, using the Wilhelmy plate method. In all cases, unusual dependencies of the interfacial tension τ on the temperature T were found. At temperatures close to the melting point of the organic phase, the interfacial tension behaves linearly, with a considerably large, positive slope. A few degrees above the melting point a phase transition occurs, and the dependence τ = f(T) becomes parabolical, resembling the water-alcohols systems with lower numbers of carbon atoms. The results obtained are interpreted in terms of interface structure and solid-like monolayer formed on the interface. © 1993 Academic Press, Inc.