Dynamics of incipient carbon particle formation in a stabilized ethylene flame by in situ extended-small-angle and wide-angle X-ray scattering

Simultaneous small-angle and wide-angle X-ray scattering (SAXS and WAXS) were used to measure several properties of the nanoparticles and soot being produced and undergoing condensation and phase changes below a stabilizing cooling plate inserted in an ethylene diffusion flame. From the SAXS data several distinct size modes appeared showing interdependent changes in the size, shape/morphology, and concentrations over the time of the experiment. The WAXS data contained information on the internal atomic-level structure of the nanoparticles and soot. They also provided important information on the onset and evolution of the condensation of particles onto the plate and the graphitization process. The concentrations of particles were determined quantitatively from the SAXS data. A very important result was the strong increase for sizes smaller than 100 angstrom, which increased drastically to very high values with number concentrations orders of magnitude higher than normally reported from flames. The results and methods applied are of interest for future studies of dynamics related to condensation and material synthesis of carbon- and non-carbon based nanoparticles in the gas phase and during deposition on surfaces.