Continuous size- and shape-selective separation of nanoparticles

点击翻译按钮获取中文摘要

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.