Kwok Sylvie, Botet Robert, Sharpnack Lewis, Cabane Bernard
Laboratoire Colloïdes et Matériaux Divisés - Chemistry, Biology and Innovation (CBI) UMR8231, ESPCI Paris, CNRS, PSL*Research University, 10 rue Vauquelin, 75005 Paris, France.
Soft Matter. 2020 Mar 11;16(10):2426-2430. doi: 10.1039/c9sm01772k.
We have discovered the existence of polydisperse high internal-phase-ratio emulsions (HIPE) in which the internal-phase droplets, present at 95% volume fraction, remain spherical and organise themselves according to Apollonian packing rules. These polydisperse HIPEs are formed by emulsifying oil dropwise in a surfactant-poor aqueous continuous phase. After stirring has ceased, their droplet size distributions begin to evolve spontaneously and continuously through coalescence towards well-defined power laws with the Apollonian exponent. Small-angle X-ray Scattering performed on aged HIPEs demonstrate that the droplet packing structure agrees with that of a numerically simulated random Apollonian packing. We argue that when such concentrated emulsions are allowed to evolve, the coalescing droplets must obey volume and sphericity conservation. This leads to a mechanism that differs from typical coalescence in dilute emulsions.
我们发现了多分散高内相比乳液（HIPE）的存在，其中内相液滴的体积分数为95%，保持球形，并根据阿波洛尼奥斯堆积规则自行排列。这些多分散HIPE是通过将油逐滴乳化在表面活性剂含量低的水连续相中形成的。搅拌停止后，它们的液滴尺寸分布开始通过聚结自发且持续地演变为具有阿波洛尼奥斯指数的明确幂律。对老化的HIPE进行的小角X射线散射表明，液滴堆积结构与数值模拟的随机阿波洛尼奥斯堆积结构一致。我们认为，当这种浓缩乳液发生演变时，聚结的液滴必须遵守体积和球形守恒。这导致了一种不同于稀乳液中典型聚结的机制。
