Materials characterization of surfaces of water drops with surfactants by acoustic means: The need for a microgravity environment

Abstract

The goal of this laboratory’s ground-based and microgravity research is to determine the rheological properties of liquid drops of single or multiple components in the presence or absence of surface active materials by exciting drops into their quadrupole resonance and observing their free decay. The resulting data coupled with appropriate theory should enable one to understand better the physics of the underlying phenomena, providing a better foundation than earlier empirical results could. The space environment makes an idealized geometry available (spherical drops) so that theory and experiment can be properly compared, and allows a ‘‘clean’’ environment, namely, an environment in which no solid surfaces come in contact with the drops during the test period. Moreover, by considering the oscillations of intentionally deformed drops in microgravity, a baseline is established for interpreting surface characterization experiments done on the ground by this and other groups. Results of work at Yale and in the first United States Microgravity Laboratory (USML 1, summer 1992) will be presented. [Work supported by NASA through JPL Contract No. 958722.]