Third party funded individual grant
Start date : 01.01.2018
End date : 31.03.2021
Nanoparticle growth
and aggregation in spray flames: in situ diagnostics
The functional properties of nanoparticles produced by spray flame synthesis (SFS) mainly depend on composition and morphology. Using advanced optical techniques, this project investigates particle growth and aggregation to correlate particle characteristics in the flame with the prevailing boundary conditions during the synthesis, such as the type of precursor, its concentration, solvent and volumetric flow rates and thus substantially contributes to a better understanding of the process.
The method of Wide-Angle Light-Scattering (WALS) will be further developed and adapted to the conditions of the SFS to allow for the in situ determination of particle characteristics (mainly radius of gyration and fractal dimension) with high temporal and spatial resolution for the first time. The technique will be extended for the evaluation of droplet sizes in order to measure particles and droplets simultaneously over a wide range of flame regions. Varying the boundary conditions allows for the efficient acquisition of a large number of data sets for the standard SpraySyn burner. Exploratory investigations on particle systems relevant in the SPP shall clarify the applicability of laser-induced incandescence for the determination of primary particle diameters of these materials. This technique shall be combined with the WALS-technique in a later project phase.
In addition to the central project, a number of bilateral collaborations have been agreed upon. All of them aim at improving the understanding of the entire cause-and-effect chain in SFS processes. In particular, detailed investigations by WALS are foreseen - also based on the results of groups performing numerical simulations - for those conditions, where small changes in the initial conditions result in significant changes of the SFS process.