Oscillating bubble experiments performed during the STS-95 mission in November 1998

Abstract: The aim of the experimental study was to characterise the dynamic interfacial tension response of surfactant solutions to high and low frequency harmonic and square pulse transient disturbances of a bubble surface area. Assuming radial transport and a diffusion controlled adsorption the experiments yield simultaneously the diffusion coefficient of the studied surfactant molecule. As an example, the dynamic surface behaviour of the model surfactant dimethyl dodecyl phosphine oxide was studied during the STS-95 space shuttle mission. The results obtained for five surfactant concentrations have been analysed and compared with ground-based experiments performed under comparable experimental conditions using the original flight module. In the re-flight STS-107 of the "oscillating bubble module", called FAST (Facility for Adsorption and Surface Tension), the completion of the STS-95 mission is planned, including studies of micellar concentrations in order to study the effect of micelle formation/dissolution on dynamic surface properties quantitatively.