Advanced MD simulations of heterogeneous nucleation of binary colloids

二元胶体异质成核的高级 MD 模拟

• 批准号: 51462579
• 负责人: Professor Dr. Christian Holm
• 金额: --
• 依托单位: Institut für Computerphysik (ICP)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/51462579?language=en
• 关键词: Advanced; MD; simulations; heterogeneous; nucleation

We plan to investigate heterogeneous nucleation in a 3D colloidal model system consisting of spherical particles. These colloids can interact via different potentials; as a test system for our methods we are using uncharged spheres interacting via Lennard-Jones potential, confined by planar or structured walls to facilitate heterogeneous nucleation. In the second funding period, we plan to extend our investigations to charged spheres, thereby mimicking the experimental systems proposed by P. Wette and H. J. Sch¨ope. We want to study heterogeneous nucleation in these systems by introducing smooth or structured charged walls, or by investigating a bidisperse system consisting of small and large charged spheres, in which the big spheres can both act as nucleation seeds or counteract nucleation, depending on size ratio of the binary suspension. In our studies we will employ advanced MD algorithms using forward-flux and umbrella sampling, that we develop in collaboration with the groups of Schilling and Horbach. Both methods have proved to be very efficient for nucleation studies, and should enable us to extract nucleation rates, size and shape of the critical nuclei, free energy barriers, and simultaneously should give us insight into the nucleation pathways. At a later stage we plan to investigate the role of hydrodynamic interactions on the nucleation kinetics.

我们计划研究由球形颗粒组成的 3D 胶体模型系统中的异质成核，这些胶体可以通过不同的电势相互作用；作为我们方法的测试系统，我们使用由平面或结构化壁限制的不带电球体通过 Lennard-Jones 电势相互作用。为了促进异质成核，我们计划将我们的研究扩展到模拟带电球体，从而掌握 P. Wette 和 H. J. 提出的实验系统。我们希望通过引入光滑或结构化的带电壁，或者通过研究由小和大带电球体组成的双分散系统来研究这些系统中的异质成核，其中大球体既可以充当成核种子，也可以抵消成核，在我们的研究中，我们将采用先进的 MD 算法，该算法使用前向通量和伞形采样，这两种方法都已被证明是我们与 Schilling 和 Horbach 团队合作开发的。对于成核研究非常有效，并且应该使我们能够提取关键核的成核速率、尺寸和形状、自由能势垒，同时应该让我们深入了解成核路径。在稍后阶段，我们计划研究流体动力学的作用。相互作用对成核动力学的影响。