Measurement of the interface tension of immiscible liquids interface

Interfacial tension and its temperature coefficient between silicone oil (KF96L-2cSt, 5cSt, KF96-10cSt, 20cSt) and fluorinert (FC-40, 3283, 43, 70) were measured by an image processing with fitting a drop shape to a theoretical one. Interfacial tension and the temperature coefficient are important property when the marangoni convection in a crystal growth technique with a liquid encapsulation system is investigated in a laboratory, by substituting aforementioned liquids for melts. These were successfully measured with the standard deviation less than 0.4%, while the tensions were also measured by a commercial tensiometer at a time with the standard deviation, about 3%. Empirical formulas for interfacial tensions at certain temperature were obtained within ±0.02-0.16 mN/m of accuracies, which were about 1/3-1/10 of those from the commercial tensiometer.