Continuous nonaqueous sol-gel synthesis of metal oxide nanoparticles in microfluidic systems and its monitoring by impedance measurement

• Applicants: Professor Dr. Andreas Dietzel; Professor Dr. Georg Garnweitner
• Subject Area: Mechanical Process Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 542142265

The non-aqueous sol-gel synthesis can lead to highly defined, partially monodisperse nanoparticles with high crystallinity, but has so far been predominantly limited to batch operation. While its (quasi-)continuous implementation in microfluidic systems would allow highly improved mixing and promises fundamentally better control, only single studies on this topic have so far been reported. The primary goal of this project is therefore to gain comprehensive understanding on the quasi-continuous microfluidic implementation of the non-aqueous synthesis of metal oxide nanoparticles. This includes first establishing the synthesis of two metal oxides as model systems while evaluating different reaction routes (droplet-based system or plug flow). Subsequently, process-property functions are worked out by means of parameter variations of the synthesis, whereby monodisperse primary nanoparticles or aggregate structures with specific morphologies are aimed at. In parallel, impedance spectroscopy will be established as an in situ measurement technique to track the progress of the reaction. In addition to tracking the fluid phases, the possibility of simultaneously recording the reactant concentration and ideally tracking the particle growth will be evaluated. This should enable systematic spatially and thus time-resolved tracking of nanoparticle formation and growth. Finally, the obtained reaction and growth kinetics will be used to model particle synthesis by means of population balance equations.

• DFG Programme: Research Grants