Bubble formation in catanionic surfactant solutions under constant-flow conditions

Two catanionic surfactants were prepared in this work. Equilibrium and dyna mic surface tensions and bubble volumes at detachment from a single orifice under constant-now conditions were obtained experimentally for aqueous sol utions of these two surfactants, While the catanionic surfactants were very effective in depressing the equilibrium surface tension, the dynamic surfa ce tension data revealed that the surface relaxation for the catanionic sur factants was insignificant in the time period studied. The bubble formation results showed that the bubble volumes at detachment in aqueous solutions of the catanionic surfactants were hardly different from those in water, Th e Ruff model, which deals with bubble formation in pure liquids, and the mo dified puff model, which considers the dynamic surface tension effect, were used to estimate the bubble volumes at detachment in surfactant solutions, It was concluded that dynamic surface tension rather than equilibrium one is responsible for the bubble formation in the catanionic surfactant soluti ons.