SBSL dynamics for bubbles modified by surfactants

A quenching isotherm of single bubble sono-luminescence (SBSL) was obtained using several surfactants. The critical concentration for the quenching decreased with increasing length of the hydrocarbon chain of the surfactant molecules. When the emission was perfectly quenched, the bubble was still trapped by the acoustic standing wave observed by laser scattering. One of the surfactants, SDS, accelerated the breathing motion of the bubble but had no effect on its maximum radius. A chemical reaction in the gas phase, probably argon rectification, proceeded in the bubble. A possible mechanism for this quenching reaction is discussed in terms of a change in the number of molecules in the bubble as a function of the acoustic intensity.