Bestimmung der Größenverteilung kolloidaler Partikel mittels Röntgen-Kleinwinkelstreuung

In this work, two different sample systems are analysed for their inner and outer structure by SAXS.The first part of this work deals with silica-coated hematite particles. It is presented that the structure of these particles can be modelled by a spheroidal core-shell form factor. With the help of an analysis program based on free distribution functions, which was developed prior to this work in our research group, the structure-defining parameters of the two semi-axes and the shell thickness are analysed for each of the nine presented samples. The geometry of the samples differs in each sample distinctly, ranging from ellipsoidal particles with a high aspect ratio to particles resembling a sphere-like structure.The main part of this work is the analysis of scattering curves obtained from PVCL/AAEM-microgels of different concentration (2.5, 15 and 25 wt%). In order to describe their complex inner structure, a "Fuzzy-Sphere" model is used, which approaches the substructure of the microgel through a radially decaying density gradient. This model was already put to good use in the analysis of several polymer colloids and manifests its applicability to the PVCL/AAEM-microgels as well. Specically the temperature dependent swelling behavior of the microgel is studied with the help of simulations. In accordance with theory, a decrease of the strongly cross-linked microgel periphery is observed towards higher temperatures. Furthermore, it is observed that for high concentrations additional oscillations appear in the scattering curves at low temperatures (10 to 20 deg C), indicating particles with a very sharp density gradient near the surface