The role of surfactant headgroup, chain length, and cavitation microstreaming on the growth of bubbles by rectified diffusion

Abstract

The role of a surfactant on the rate of bubble growth via rectified diffusion during acoustic cavitation has been investigated. The charge of the headgroup of ionic surfactants did not affect the bubble growth rate at low surface loadings. However, at higher surface loading, the growth rate was significantly dependent upon the type and charge of the headgroup. Dodecyl trimethyl ammonium chloride (DTAC) caused a greater increase in growth rate than sodium dodecyl sulfate (SDS) or dodecyl dimethyl ammonium propane sulfonate (DDAPS). With charge suppressed by the addition of salt, DDAPS showed the highest growth rate. Particle-image velocimetry (PIV) has been used to characterize the microstrea..