Zhang Haodong, Wu Yanchen, Wang Fei, Guo Fuhao, Nestler Britta
Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, Karlsruhe 76131, Germany.
Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestraße 30, Karlsruhe 76133, Germany.
Langmuir. 2021 May 4;37(17):5275-5281. doi: 10.1021/acs.langmuir.1c00275. Epub 2021 Apr 22.
Currently, multiple emulsions via liquid-liquid phase separation in ternary polymer solutions have sparked considerable interest because of its remarkable potential in physical, medical, and biological applications. The transient "onion-like" multilayers are highly dependent on the evolution kinetics, which is challenging to be scrutinized in experiments and has not yet been fully understood. Here, we report a thermodynamically consistent multicomponent Cahn-Hilliard model to investigate the kinetics of multiple emulsions by tracing the temporal evolution of the local compositions inside the emulsion droplets. We reveal that the mechanism governing the kinetics is attributed to the competition between surface energy minimization and phase separation. Based on this concept, a generalized morphology diagram for different emulsion patterns is achieved, showing a good accordance with previous experiments. Moreover, combining the analysis for the kinetics and the morphology diagram, we predict new emulsion structures that provide general guidelines to discovery, design, and manipulation of complex multiphase emulsions.
目前，三元聚合物溶液中通过液-液相分离形成的多重乳液因其在物理、医学和生物应用方面的巨大潜力而引发了广泛关注。瞬态的“洋葱状”多层结构高度依赖于演化动力学，这在实验中难以仔细研究，并且尚未得到充分理解。在此，我们报告了一个热力学一致的多组分Cahn-Hilliard模型，通过追踪乳液滴内部局部组成的时间演化来研究多重乳液的动力学。我们揭示了控制动力学的机制归因于表面能最小化和相分离之间的竞争。基于这一概念，得到了不同乳液模式的广义形态图，与先前的实验结果吻合良好。此外，结合动力学分析和形态图，我们预测了新的乳液结构，为复杂多相乳液的发现、设计和操控提供了通用指导方针。
