Measurement of ultralow interfacial tension with ADSA using an entropic edge-detector

The ultralow interfacial tension of the two-liquid phase of a ternary syste m 1-propanol-n-heptane-water was determined with a pendant drop method usin g the axisymmetric drop shape analysis (ADSA) methodology. Because the two liquid phases of the ternary system are practically miscible at temperature s near the critical solution temperature, the drops are small and difficult to distinguish from their surroundings. Consequently, some difficulties ap pear in the automatic drop analysis, mainly in the profile detection step. An entropic edge-detection method based on the Jensen-Shannon divergence is applied for this purpose. To complete the study, the temperature dependenc e of the interfacial tension of the two-liquid phase of the ternary system was investigated. (C) 1999 Elsevier Science B.V. All rights reserved.