In situ Time-resolved Characterization of Particle Systems in the Continuous Synthesis Process by Means of a Newly-developed USAXS/WAXS Laboratory Camera

• Applicant: Professor Dr.-Ing. Hermann Nirschl
• Subject Area: Mechanical Process Engineering
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 262980686

Nanostructured particle systems are manufactured in many different ways and in the meantime have a high application potential due to extensive research efforts. In a continuous synthesis of nanoscale particle systems with defined properties for material-specific applications, however, it is necessary to systematically investigate the early stages of particle formation so as to better understand and control the ongoing synthesis processes, and to be able to reach the expected product properties. So far this has not yet been successfully realized for many processes as a result of enormous metrological requirements. A non-destructive measurement technique that is also suitable for liquid phases is the so-called X-ray scattering, which is very suitable for in situ process analysis. The objective of this proposed project is to develop a new ultra small- and wide-angle X-ray scattering apparatus (USAXS/WAXS) for time-resolved in situ characterization of particle systems in a continuous synthesis process. The specific modular design of the measuring system allows in situ analysis of the particle formation process by means of an appropriate adjustment of the optics to be used, the sample chamber and the measuring technique for the detection of the scattered radiation. Compared to the current state of the art, the distance between the sample and the detector can be increased by use of a corresponding X-ray optical component, resulting in an approximately 10-fold improvement in the resolution of the minimum scattering vector. Consequently, the use of the new measuring system makes it possible to analyze particulate structures with a size up to about 400 nm. Thus, the measured USAXS scattering curves provide the useful information for the structure elucidation both on the primary particle level and on the aggregate level. In addition, the simultaneous detection of the scattering curves at the wide angle enables characterization of crystal properties. The newly-developed USAXS/WAXS measuring system is intended to be tested by means of continuous synthesis of silica multiplets and core-shell magnetite-silica composites. For this purpose, an appropriate microreactor system is to be connected to the measuring cell, so that the process taking place in the particle synthesis can be studied in a time-resolved manner by adjusting the delay time. The main objective is to ensure the required product quality (particle size distribution, aggregate properties, distribution of the shell thickness, etc.) through in situ continuous monitoring and control of processes in the reacting system.

• DFG Programme: Research Grants