Department of Physical Chemistry, Institute of Chemistry, University of Campinas , P.O. Box 6154, Campinas - 13084-862, Brazil.
Langmuir. 2014 Jan 28;30(3):727-32. doi: 10.1021/la404513h. Epub 2014 Jan 16.
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). Here we investigate soap bubbles formed from simple solutions of a cationic surfactant (cetyltrimethylammonium bromide - CTAB) and sodium salicylate. The interaction of salicylate ions with CTAB leads to the formation of wormlike micelles (WLM), which yield a viscoelastic behavior to the liquid film of the bubble. We demonstrate that these elastic bubbles collapse at a velocity up to 30 times higher than the Taylor-Culick limit, which has never been surpassed. This is because during the bubble inflation, the entangled WLM chains stretch, storing elastic energy. This extra energy is then released during the rupture of the bubble, yielding an additional driving force for film retraction (besides surface tension). This new mechanism for the bursting of elastic bubbles may have important implications to the breakup of viscoelastic sprays in industrial applications.
慢动作成像显示，肥皂泡的破裂通常会使液膜以恒定速度（称为泰勒-卡利克速度）回缩。在这里，我们研究了由阳离子表面活性剂（十六烷基三甲基溴化铵 - CTAB）和水杨酸钠的简单溶液形成的肥皂泡。水杨酸盐离子与 CTAB 的相互作用导致形成蠕虫状胶束（WLM），从而使气泡的液膜具有粘弹性。我们证明，这些弹性气泡的坍塌速度比泰勒-卡利克极限高 30 倍，这是前所未有的。这是因为在气泡膨胀过程中，缠结的 WLM 链伸展，储存弹性能量。在气泡破裂时，这部分额外的能量被释放出来，为膜回缩提供了额外的驱动力（除了表面张力）。这种弹性气泡破裂的新机制可能对工业应用中粘弹性喷雾的破裂具有重要意义。
