Understanding and controlling the lateral hydrogel shell deformation of core/shell microgels at air/waterinterfaces for smart surface nanopatterning

本项目的目的是调查和澄清的自由浮动的胶体单层的核/壳微凝胶在空气/水界面的横向扩展。此外，单层延伸将被用作一种智能纳米图案化技术，用于制备相互作用的等离子体表面涂层。这些工作的基础将是具有硬核和软的可变形水凝胶壳的微凝胶。与纯聚合物微凝胶相反，这些颗粒自发地形成高度有序的、自由浮动的单层。在之前的概念验证研究中，我们可以证明单层在几分钟到几小时的时间尺度上横向扩展。这种延伸的确切起源，其动力学和影响延伸行为的结构参数目前尚不清楚。我们只能证明，延伸发生得非常缓慢，并且在延伸过程中单层的有序度几乎不受影响。基于这些知识，我们要研究的动力学的不同结构和外部参数的依赖性的扩展。为此，我们将合成不同的柔软性，交联剂分布和电荷的核/壳微凝胶。这些将根据其溶胀能力和表面活性来表征。中心任务是确定界面覆盖区和未覆盖区之间的表面压力差。我们将使用的自由浮动单分子膜转移到玻璃基板上后，不同的停留时间，研究不同的显微镜技术的微观结构的时间演变。通过改变界面处单层面积的大小和通过表面活性剂降低表面张力，我们将确定如何通过外部参数控制延伸动力学。此外，对于第一次，它成为可能，我们遵循的单层延伸光谱原位通过使用染料标记的核心。与此相反，具有各种尺寸的等离子体金核的微凝胶的实验将允许澄清等离子体共振耦合现象。在这里，我们也将使用原位光谱的时间依赖性实验自由浮动单分子膜。我们将通过掠入射小角X射线散射（GISAXS）原位研究微结构。有了这个，我们可以得到潜在的单层结构和光学耦合过程之间的相关性，例如局部表面等离子体共振和超晶格的衍射模式之间。实验结果将得到光学性质的理论计算的支持。该项目的结果将有助于一方面的软系统在接口的基本理解，另一方面的智能nanopatterning程序的开发，用于制备光学活性，胶体涂层。

The objectives of this project are the investigation and clarification of the lateral extension of freely floating colloidal monolayers of core/shell microgels at air/water interfaces. Furthermore, the monolayer extension will be used as a smart nanopatterning technique for the preparation of interacting, plasmonic surface coatings.The basis for these works will be microgels with hard cores and soft, deformable hydrogel shells. In contrast to purely polymeric microgels, these particles form highly ordered, freely floating monolayers spontaneously. In a previous proof-of-concept study we could show that the monolayers expand laterally on timescales of minutes to hours. The exact origin of this extension, its kinetics and the structural parameters influencing the extension behavior are currently unknown. We could merely show that the extension occurs very slowly and that the degree of order of the monolayer during extension remains nearly unaffected. Based on this knowledge we want to study the kinetics of extension in dependence of different structural and external parameters. For this, we will synthesize core/shell microgels of different softness, cross-linker distribution and charge. These will be characterized with respect to their swelling capacity and surface activity. A central task will be the determination of the difference in surface pressure between covered and uncovered areas of the interface. We will use the transfer of the freely floating monolayers onto glass substrates after different dwell times to study the temporal evolution of the microstructure by different microscopy techniques. By varying the size of the monolayer area at the interface and the reduction of the surface tension through a surfactant, we will identify how the extension kinetics can be controlled by external parameters. Furthermore, for the first time it becomes possible for us to follow the monolayer extension spectroscopically in-situ by the use of dye-labeled cores. In contrast to this, experiments with microgels featuring plasmonic gold cores of various sizes will allow to clarify plasmon resonance coupling phenomena. Here we will also use in-situ spectroscopy for time dependent experiments on freely floating monolayers. We will investigate the microstructure in-situ by grazing-incidence small-angle X-ray scattering (GISAXS). With this we can derive potential correlations between monolayer structure and optical coupling processes, e.g. between localized surface plasmon resonances and diffraction modes of the superlattice. The experimental findings will be supported by theoretical calculations of the optical properties. The results of this project will contribute on the one hand to the fundamental understanding of soft systems at interfaces and on the other hand to the development of smart nanopatterning procedures for the preparation of optically active, colloidal coatings.