Institut de Physique de Rennes, UMR 6251 CNRS/Université de Rennes 1, 35042 Rennes Cedex, France.
Phys Rev Lett. 2013 Aug 30;111(9):094501. doi: 10.1103/PhysRevLett.111.094501. Epub 2013 Aug 26.
Liquid foams are widely used in industry for their high effective viscosity, whose local origin is still unclear. This Letter presents new results on the extension of a suspended soap film, in a configuration mimicking the elementary deformation occurring during foam shearing. We evidence a surprising two-step evolution: the film first extends homogeneously, then its extension stops, and a new thicker film is extracted from the meniscus. The second step is independent of the nature of the surfactant solution, whereas the initial extension is only observed for surfactant solutions with negligible dilatational moduli. We predict this complex behavior using a model based on Frankel's theory and on interface rigidification induced by confinement.
液体泡沫因其高有效粘度而在工业中得到广泛应用，但其局部起源尚不清楚。本信函介绍了在模仿泡沫剪切过程中基本变形的悬浮肥皂膜延伸的新结果。我们证明了一个惊人的两步演化过程：膜首先均匀地延伸，然后延伸停止，并且从弯月面中提取出较厚的新膜。第二步与表面活性剂溶液的性质无关，而初始延伸仅在具有可忽略的拉伸模量的表面活性剂溶液中观察到。我们使用基于 Frankel 理论和由约束引起的界面固化的模型来预测这种复杂的行为。
