Single droplet combustion of precursor/solvent solutions for nanoparticle production: Optical diagnostics on single isolated burning droplets with micro-explosions

In order to understand the droplet micro-explosions occurring during single droplet combustion of the flame spray pyrolysis (FSP) precursor/solvent solutions, the optical techniques, such as, interferometric particle imaging (IPI) and standard rainbow refractometry (SRR), were applied to the single droplet combustion of Tin (II) 2-ethylhexanoate/Xylene. The changes of droplet size and rainbow pattern were detected using IPI and SRR, respectively. A multicomponent diffusion limited model was developed to simulate the experimental changes of droplet size and rainbow pattern, and to further estimate the mass and heat transfer inside the burning droplets. The rainbow patterns of the precursor/solvent droplets with micro-explosions show significantly different insights comparing to single component droplets. The results demonstrate that the evolutions of rainbow patterns of the burning droplets and the time needed for droplet micro-explosions are strongly dependent on the concentration of the metal-organic precursor. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.