Axisymmetric Drop Shape Analysis (ADSA) for the determination of surface tension and contact angle

A drop shape analysis technique called Axisymmetric Drop Shape Analysis (ADSA) has been developed in our laboratory over the last twenty years. ADSA is a powerful technique for the measurement of interfacial tensions and contact angles of pendant drops, sessile drops, and bubbles. In essence, it relies on the best fit between theoretical Laplacian curves and an experimental profile. Despite the general success of ADSA, deficient results may be obtained for drops close to spherical shape. Since the sources of these limitations were unknown, the entire ADSA technique, including hardware and software, has been reviewed. The key element of the new generation of ADSA is the modularization of the software, because a firm fixed package would not be suitable for all experimental situations. Another novel feature of the methodology is the development of a quantitative criterion, i.e., a shape factor, that determines the range of drop shapes, in which ADSA succeeds or fails.