Computational evaluation of the theoretical image fitting analysis - axisymmetric interfaces (TIFA-AI) method of measuring interfacial tension

A new method, theoretical image fitting analysis for axisymmetric interfaces (TIFA-AI), has recently been presented for measuring the interfacial properties of liquids, such as the interfacial tension and contact angles, by analysing the shape of an axisymmetric liquid-fluid interface without the use of apex coordinates. The versatility and accuracy of TIFA-AI have been shown by conducting experiments with various configurations: liquid bridges, sessile and pendant drops, and liquid lenses. In this paper, the performance of TIFA-AI is evaluated in detail by using 'synthetic' images of pendant drops and liquid bridges, which allows one to study separately the influence of different factors in the experiment. A simple method for generating such synthetic images of pendant drops and liquid bridges is described. The synthetic images are processed by TIFA-AI and the resulting interfacial tensions are compared with the (known) true values. The influence of errors associated with the calibration process and the effects of reducing the quality of the image on the results provided by TIFA-AI is analysed. As a general conclusion, one can assert that TIFA-AI provides accurate values of the interfacial tension for pendant drops and liquid bridges for a wide range of experimental conditions.