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.

我们计划在一个由球形颗粒组成的三维胶体模型系统中研究异相成核。这些胶体可以通过不同的电位相互作用;作为我们方法的测试系统，我们使用不带电的球体通过Lennard-Jones电位相互作用，由平面或结构化壁限制，以促进异质成核。在第二个资助期，我们计划将我们的研究扩展到带电球体，从而模仿P. Wette和H. J. Schöope。我们要研究在这些系统中的异质成核，通过引入光滑或结构化的带电壁，或通过调查由小和大的带电球体，其中大的球体可以作为成核种子或抵消成核，取决于尺寸比的二元悬浮液组成的双分散系统。在我们的研究中，我们将采用先进的MD算法，使用前向通量和伞形采样，我们与Schilling和霍尔巴赫的小组合作开发。这两种方法已被证明是非常有效的成核研究，并应使我们能够提取成核率，大小和形状的临界核，自由能垒，同时应该给我们洞察成核途径。在稍后的阶段，我们计划调查的成核动力学的流体动力学相互作用的作用。