König Björn, Ronsin Olivier J J, Harting Jens
Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Forschungszentrum Jülich, Fürther Str. 248, 90429 Nürnberg, Germany.
Department of Chemical and Biological Engineering and Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fürther Straße 248, 90429 Nürnberg, Germany.
Phys Chem Chem Phys. 2021 Nov 10;23(43):24823-24833. doi: 10.1039/d1cp03229a.
The evolution of the microstructure due to spinodal decomposition in phase separated mixtures has a strong impact on the final material properties. In the late stage of coarsening, the system is characterized by the growth of a single characteristic length scale ∼ . To understand the structure-property relationship, the knowledge of the coarsening exponent and the coarsening rate constant is mandatory. Since the existing literature is not entirely consistent, we perform phase field simulations based on the Cahn-Hilliard equation. We restrict ourselves to binary mixtures using a symmetric Flory-Huggins free energy and a constant composition-independent mobility term and show that the coarsening for off-critical mixtures is slower than the expected -growth. Instead, we find to be dependent on the mixture composition and associate this with the observed morphologies. Finally, we propose a model to describe the complete coarsening kinetics including the rate constant .
相分离混合物中旋节线分解导致的微观结构演变对最终材料性能有强烈影响。在粗化后期，系统的特征是单一特征长度尺度∼的增长。为了理解结构-性能关系，必须了解粗化指数和粗化速率常数。由于现有文献并不完全一致，我们基于Cahn-Hilliard方程进行相场模拟。我们使用对称的Flory-Huggins自由能和与组成无关的恒定迁移率项，将研究限制在二元混合物上，并表明非临界混合物的粗化比预期的-增长慢。相反，我们发现取决于混合物组成，并将其与观察到的形态联系起来。最后，我们提出了一个模型来描述包括速率常数在内的完整粗化动力学。
