The beauty of soap bubbles has long fascinated children and adults, and a quantitative model for explaining their burst was first developed by Lord Rayleigh in 1891. Slow-motion imaging of the rupture of soap bubbles generally shows the edges of liquid films retracting at a constant speed (known as the Taylor-Culick velocity), which is determined by momentum balance for the liquid rim collected at the film edge. In this talk we will report on our investigation[1] of soap bubbles formed from simple solutions of a cationic surfactant (cetyltrimethylammonium bromide – CTAB) and sodium salicylate, which have a viscolestic behavior due to the formation of “polymer-like” surfactant aggregates known as wormlike micelles. We demonstrate that these elastic bubbles collapse at a velocity up to thirty times higher than the Taylor-Culick limit, which has never been surpassed. This can be explained by a simple model that includes the elastic energy stored in the liquid film while the bubble is inflated, which is released when the film is ruptured, yielding an additional driving force for film retraction (besides surface tension). This new mechanism for the bursting of elastic liquid bubbles may have important implications to the breakup of viscoelastic sprays in industrial applications.
[1] E. Sabadini et al., Langmuir 30, 727 (2014).
