Analysis of Amplitude- and Phase-Frequency Characteristics of Oscillating Bubble System with Closed Measuring Cell

Equations for the amplitude- and phase-frequency characteristics of oscillating bubble systems in a closed measuring cell are derived which are in a good qualitative agreement with experiments performed under ground and microgravity conditions (STS-95 and STS-107). Using calibration experiments with the pure solvent water it was possible to obtain the complex surface elasticity modulus from the respective experimental characteristics. The comparison of the high frequency limits of the measured elasticity with the theoretical dilational elasticities calculated according to the respective adsorption isotherm shows good agreement at small surfactant concentrations but large discrepancies at higher concentrations.