Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, Szeged, H-6720, Hungary.
Institute of Process Engineering, TU Dresden, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany.
Phys Chem Chem Phys. 2019 Feb 6;21(6):2910-2918. doi: 10.1039/c8cp07693f.
Thanks to the coupling between chemical precipitation reactions and hydrodynamics, new dynamic phenomena may be obtained and new types of materials can be synthesized. Here we experimentally investigate how the characteristic microscopic crystal properties affect the macroscopic pattern obtained. To shed light on such interactions, different reactant solutions are radially injected into a calcium chloride solution at different volumetric flow rates in a confined geometry. Depending on the reactants used and the flow conditions, deformed precipitate membranes have been observed due to reaction-driven viscous fingering. In such cases we show that upon injection a large number of small particles is produced in situ by the reaction at the miscible interface between the two reactant solutions. Therefore, a colloidal gel composed of those tiny particles is pushed forward by the injected aqueous solution giving rise to a viscosity gradient-driven hydrodynamic instability.
由于化学反应和流体动力学的耦合，可以获得新的动力学现象，并合成新型材料。在这里，我们通过实验研究了微观晶体特性如何影响宏观图案的形成。为了揭示这种相互作用，我们以不同的体积流速将不同的反应物溶液径向注入氯化钙溶液中，在受限的几何形状中进行实验。根据使用的反应物和流动条件，由于反应驱动的粘性指进，已经观察到变形的沉淀物膜。在这种情况下，我们表明，在注入过程中，大量的小颗粒会在两种反应物溶液的可混溶性界面处就地通过反应产生。因此，由这些微小颗粒组成的胶体凝胶被注入的水溶液向前推动，从而产生由粘度梯度驱动的流体动力学不稳定性。
