Continuous size- and shape-selective separation of nanoparticles

各向异性纳米颗粒的合成规模扩大通常导致宽宽比分布和球形颗粒作为副产物。因此，需要一个大小和形状选择分类步骤来根据应用程序的需要调整产品属性。建立球形和各向异性纳米颗粒尺寸和形状选择性分类的技术相关流程具有挑战性，需要多维颗粒表征。分析性超离心被用作中心分析方法，因为它是在广泛的尺寸范围内对悬浮中纳米颗粒进行分析的最准确的方法，并提供了有关形状各向异性的信息。此外，将使用粒子表征的标准方法来研究二维分布重建的可能性。该项目的一个关键目标是利用抗溶剂沉淀法将各向异性纳米颗粒（棒和血小板）从球体中分离出来，并根据长径比进行分类。此外，分离过程将通过多维颗粒表征的分析方法定量描述。由于大小和形状相关的粒子相互作用决定了反溶剂沉淀的结果，因此通过实验和扩展的DLVO模型对这些相互作用进行了详细的研究。此外，电泳分类的潜力是通过测量作为纳米颗粒大小，形状和纵横比的功能的电泳迁移率进行探索。该研究将以SiO2薄片和ZnO和Au棒为例进行。

Scale-up of syntheses for anisotropic nanoparticles usually results in rather broad aspect ratio distributions and spherical particles as side-products. Thus, a size and shape selective classification step is required to tune the product properties according to the needs of the application. The establishment of technical relevant processes for size and shape selective classification of spherical and anisotropic nanoparticles is challenging and requires multidimensional particle characterization. Analytical ultracentrifugation is used as central analytical method as it is the most accurate method for in-suspension analytics of nanoparticles in a broad size range and provides information regarding shape anisotropy. Additionally, standard methods of particle characterization will be used to study possibilities for the reconstruction of two-dimensional distributions.A key objective of this project is separation of anisotropic nanoparticles (rods and platelets) from spheres and classification regarding aspect ratio using antisolvent precipitation. Moreover, the separation process will be described quantitatively by analytical methods for multidimensional particle characterization. As the size and shape dependent particle interactions govern the result of antisolvent precipitation these interactions are studied in detail experimentally and by extended DLVO models. Additionally the potential of an electrophoretic classification is explored by measuring the electrophoretic mobility as a function of nanoparticle size, shape and aspect ratio.The investigations will be done exemplary for SiO2 platelets and ZnO and Au rods.