Abstract
Two catanionic surfactants were prepared in this work. Equilibrium and dynamic surface tensions and bubble volumes at detachment from a single orifice under constant-flow conditions were obtained experimentally for aqueous solutions of these two surfactants. While the catanionic surfactants were very effective in depressing the equilibrium surface tension, the dynamics surface tension data revealed that the surface relaxation for the catanionic surfactants 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. The Ruff model, which deals with bubble formation in pure liquids, and the modified Ruff 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 solutions.
