Interfacial tension between oil and water measured with a modified contour method

The interfacial tension between silicone oil and water is measured in the temperature range 18–35 °C. A novel method is used which promises prospects for the application to other liquid/liquid systems. The method is based on digital image processing of the contour of a pendant drop in combination with a pressure measurement. In contrast to existing algorithms axisymmetric drop shape analysis (ADSA) relying on iterative solutions of the Laplace equation the interfacial tension is obtained without Laplace from a force balance yielding an explicit expression for the interfacial tension.