Electron microscopy evidence of aggregation under three different size scales for soot nanoparticles in flame

Size-range analysis of diesel soot with ultra-small angle X-ray scattering

“…These onionlike structures are made from parallel graphene sheets arranged with their basal planes perpendicular to the radii of the structures. Ishiguro et al [11] have observed similar structures in diesel soot and di Stasio [12] makes similar observations on soot from a Bunsen burner fed by ethylene.…”

“…With the same technique, di Stasio [12] reports evidence of three different size scales in soot obtained from an ethylene flame. The early stage of soot inception has been studied recently in flamma using small-angle Xray scattering (SAXS) [13].…”

Spatially resolved small-angle x-ray scattering studies of soot inception and growth

“…We have tested our apparatus by performing SAXS on C 60 , which has a radius of gyration of 0.363 nm, and our results agree with neutron scattering measurements. [27] We can identify three different sources for scattering at q > 1 nm -1 : the soot nuclei observed by di Stasio [15], a polycyclic hydrocarbon such as naphthalene [16], or disordered carbon with graphitic basal planes [17]. …”

“…The larger particles of this distribution correspond to polydispersed primary particles, with properties that depend upon both the radial and axial position within the flame, and that ultimately lead to a distribution with a mean radius of gyration, <R g >, of 21 nm and a polydispersity, σ S /<R g >, of 0.2, where σ S is the width of the Schultz distribution [14]. The smaller particles, which require additional experiments before they can be identified, may be the soot nuclei observed by di Stasio [15], a polycyclic aromatic hydrocarbon such as naphthalene, which we have observed [16], and/or disordered carbons with graphitic basal planes observed by Chen and Dobbins [17]. the Porod region, the scattering intensity scales as 1/q 4 and, if the system is not too polydispersed, interference fringes may be observed that will directly provide <R g > and the polydispersity, σ/<R g >, where σ is the width of the distribution.…”

Optical Analytical Technique for Carbonaceous Particles Using Laser-Induced Electro-Avalanche Fluorescence and Laser-Induced Incandescence

“…(40) According to di Stasio, (41) carbon nanoparticles can be separated into three classes. The first is recognized as a class of primary particles (20-50 nm) that are usually reported to be subunits that make up chainlike and fractal soot aggregates.…”