The influence of ultrasound power on multibubble sonoluminescence intensity from aqueous solutions containing surface active solutes

Abstract

Water soluble surface active solutes have been found to affect the intensity of multibubble sonoluminescence (MBSL) in aqueous solutions. For example, the presence of charged surfactants enhances the MBSL intensity relative to that observed from pure water, whereas the presence of volatile surface active solutes decreases the MBSL intensity in reference to pure water [J. Phys. Chem. B 101, 10845 (1997)]. Further investigations on how ultrasound power influences the effect of surface active solutes on MBSL intensity have shown that ultrasound power plays an important role in governing the above mentioned effects. The relative enhancement in MBSL intensity by charged surfactants has been found to vary with changes in ultrasound power level; the relative enhancement decreases with an increase in the ultrasound power level. Also, the extent of MBSL quenching by alcohols has been found to increase with an increase in the applied ultrasound power level; no SL quenching at lower power levels and >80% SL quenching at higher power levels have been observed. The influence of ultrasound power on the population of ‘‘active’’ bubbles and the cavitation bubble temperature, in aqueous solutions containing surface active solutes, will be discussed in order to rationalize the observed experimental data.