Heterogeneous nucleation and microstructure formation in colloidal crystals

我们建议在本研究项目中研究不同长度尺度的单组分和多组分胶体熔体的非均质成核和微观结构演变。使用各种时间分辨光学方法，应该可以将观察到的动力学与潜在的物理机制联系起来。对于计划项目的各个方面，我们安排了与SPP内理论方面研究异质成核的项目的合作。在项目中，我们将研究不同类型的异质成核。在不同过冷程度下，研究了光滑基底上的非均相形核及其显微组织演变。我们计划在SPP内首次研究引入结构衬底，改变衬底的晶格间距和晶体结构的非均相成核和微观结构的形成。通过有控制地添加不同大小和浓度的种子，我们将诱导非均相成核，并将改变微观结构的演变，类似于金属体系中的接种。因此，结晶动力学的测定和产生的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.