Le Merrer Marie, Cohen-Addad Sylvie, Höhler Reinhard
Université Paris 6, UMR 7588 CNRS-UPMC, INSP, 4 place Jussieu, 75252 Paris Cedex 05, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Aug;88(2):022303. doi: 10.1103/PhysRevE.88.022303. Epub 2013 Aug 9.
In aqueous foams, the diffusive gas transfer among neighboring bubbles drives a coarsening process which is accompanied by intermittent rearrangements of the structure. Using time-resolved diffusing-wave spectroscopy, we probe the dynamics of these events as a function of the rigidity of the gas-liquid interfaces, liquid viscosity, bubble size, and confinement pressure. We present in detail two independent techniques for analyzing the light scattering data, from which we extract the rearrangement duration. Our results show that interfacial rheology has a major impact on this duration. In the case of low interfacial rigidity, the rearrangements strongly slow down as the pressure is decreased close to the value zero where the bubble packing unjams. In contrast, if the interfaces are rigid, rearrangement durations are independent of the confinement pressure in the same investigated range. Using scaling arguments, we discuss dissipation mechanisms that may explain the observed dependency of the rearrangement dynamics on foam structure, pressure, and physicochemical solution properties.
在水性泡沫中，相邻气泡之间的扩散气体传输驱动了一个粗化过程，该过程伴随着结构的间歇性重排。使用时间分辨扩散波谱，我们研究了这些事件的动力学与气液界面的刚性、液体粘度、气泡大小和围压的函数关系。我们详细介绍了两种独立的技术来分析光散射数据，从中提取重排持续时间。我们的结果表明，界面流变学对这个持续时间有重大影响。在低界面刚性的情况下，随着压力降低到接近气泡堆积解堵塞的零值，重排强烈减慢。相反，如果界面是刚性的，在相同的研究范围内，重排持续时间与围压无关。使用标度论证，我们讨论了可能解释观察到的重排动力学对泡沫结构、压力和物理化学溶液性质的依赖性的耗散机制。
