Heterogeneous nucleation and microstructure formation in colloidal crystals

我们建议研究不同粒子相互作用的单组分和多组分胶体熔体中的非均质成核和微结构演化，这些粒子相互作用跨越了本研究计划中存在的不同长度尺度。使用各种时间分辨光学方法，应该有可能将观察到的动力学与潜在的物理机制联系起来。对于计划项目的所有方面，我们安排了与从SPP内的理论方面研究非均相成核的项目的合作。在该项目中，我们将研究不同类型的异质成核。对于不同程度的过冷度，我们将研究光滑衬底上的异质形核以及随后的组织演变作为衬底曲率的函数。我们计划首次在SPP中研究引入结构衬底的异质形核和微结构的形成，改变衬底的晶格间距和晶体结构。通过控制添加不同尺寸和浓度的晶种，我们将诱导异质形核，并将改变组织演变，类似于金属系统中的孕育。因此，结晶动力学的测定和微观结构的分析是最重要的。

We propose to investigate heterogeneous nucleation and the microstructure evolution in onecomponent and multi-component colloidal melts of various particle interaction bridging different length scales present within this research program. Using various time resolved optical methods, it should be possible to link the observed kinetics to the underlying physical mechanisms. For all aspects of the planned project we arranged collaborations with projects studying heterogeneous nucleation from the theoretical side within the SPP. Inside the project we will look at different types of heterogeneous nucleation. Heterogeneous nucleation on smooth substrates and the following microstructure evolution will be investigated as function of the substrate curvature for different degrees of undercooling. For the first time within the SPP we plan to investigate the heterogeneous nucleation and the microstructure formation introducing structured substrates, varying the lattice spacing and the crystal structure of the substrate. By controlled addition of seeds with various size and concentration we will induce heterogeneous nucleation and will modify the microstructure evolution in close analogy to inoculation in metallic systems. Thereby the determination of the crystallization kinetics and the analysis of the arising microstructure are the most important points.