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

• An experimental method is presented for the interfacial tension between two liquids.
• The bubble contour is evaluated by image processing.
• A force balance is used for the interfacial tension.
• The Laplace equation relating internal pressure and curvature is not involved.

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.

The interfacial tension between silicon oil (AK20) and water measured by a novel contour method not using the Laplace equation.Figure optionsDownload as PowerPoint slide