Surface tension response to area changes using axisymmetric drop shape analysis

The pulsating bubble and the film balance techniques are classical methods for measuring the dynamic surface tension response of surfactant solutions to area changes. Both techniques have advantages and disadvantages, and have been employed to study a variety of surfactant systems. Recently, a motor-controlled syringe has been developed in our laboratory which, when used in conjunction with a drop shape technique known as axisymmetric drop shape analysis (ADSA), is capable of performing many of the experiments traditionally conducted using either the pulsating bubble surfactometer or the film balance. In addition, ADSA has a number of distinct advantages over more conventional approaches. A comparison of these three methodologies is made and new data relating the surface tension response of three concentrations (8, 12 and 16 mM) of sodium dodecyl sulfate (SDS) solutions to surface area changes is reported.