Department of Chemistry, University of Alaska Anchorage, Anchorage, Alaska 99508, USA.
J Chem Phys. 2012 Nov 14;137(18):184701. doi: 10.1063/1.4762828.
The experiments described here are at the intersection of two dynamical systems with long pedigrees for forming interesting patterns: liquid droplet impacts and precipitation membranes. Drops of calcium chloride solution have been allowed to impact on a deep pool of sodium silicate solution. The precipitation structures produced by this method, and how these structures subsequently evolve, have been observed. Many interesting patterns can be formed from this process. It is observed that the precipitation patterns produced are sensitive to the shape of the drop when it impacts the pool's surface. Also, at large drop heights, we determine two critical Weber numbers: one for forming a skirt around the structures and the other for breakup of the structures. On longer time scales, open tubes grow from the closed precipitation shell produced at lower drop heights. These tubes can appear in large numbers with nearly identical sizes and diameters as small as 50 μm.
液滴冲击和沉淀膜。让氯化钙溶液滴落在硅酸纳溶液的深池中。已经观察到了这种方法产生的沉淀结构以及这些结构随后的演变。这个过程可以形成许多有趣的图案。观察到，沉淀图案的形成对液滴撞击池表面时的形状敏感。此外，在较大的液滴高度下，我们确定了两个临界韦伯数：一个用于在结构周围形成裙边，另一个用于结构的破裂。在较长的时间尺度上，从较低液滴高度产生的封闭沉淀壳中生长出开口管。这些管可以以大量出现，几乎具有相同的尺寸，直径小至 50μm。
