Planar laser-based imaging measurements of fluorescence and particle scatteringhave been obtained during flame synthesis of iron-oxide/silica superparamagneticnanocomposites. The theory and application of laser-induced fluorescence, thespectroscopy of FeO(g), and the experimental approach for measurement of gas phaseprecursors to particle formation are discussed. The results show that the vapor phaseFeO concentration rapidly rises at the primary reaction front of the flame and is verysensitive to the amount of precursor added, suggesting nucleation-controlled particlegrowth. The FeO vapor concentration in the main nucleation zone was found to beinsensitive to the amount of silicon precursor injected, indicating that nucleation occurredindependently for the iron and silicon components. Light scattering measurements indicate that nanocomposite particles sinter faster than single component silica, in agreement with TEM measurements.
Additional Particle Information
B.K. McMillin, P. Biswas, and M.R. Zachariah, "In-Situ Characterization of Vapor-Phase Growth of Iron Oxide Silica Nanocomposites; Part I: 2-D Planar Laser Induced Fluorescence and MIE Imaging" J. Mat. Res. 11, 1552 ( 1996)
Almquist C. and Biswas P.: "Role of synthesis method and particle size of nanostructured titanium dioxide on its photoactivity", J. of Catalysis, vol. 212 (2), 145-156, 2002. Kulkarni P. and Biswas P. "Morphology of Nanostructured Films for Environmental Applications: Simulation of Simultaneous Sintering and Growth", J.of Nanoparticle Research, vol. 5 (3-4): 259-268, 2003. Biswas P., Choi M., Fissan H., Okuyama K., Pui D. and Schoonman, J. "International Symposium on ‘Nanoparticles: Aerosols and Materials", Pusan, Korea, July 5-6, 2001", J. Nanoparticle Res., vol. 5, 573-576, 2003. Rodriguez S., Almquist C., Tai Gyu Lee, T.G.; Furuuchi M.; Hedrick E. and Biswas P.: “A Mechanistic Model for Mercury Capture with In Situ Generated Titania Particles: Role of Water Vapor, J. Air and Waste Mgmt. Associn., vol. 54, 149-156, 2004. Lee T.G., Biswas P. and Hedrick E.: “Overall Kinetics of Heterogenous Elemental Mercury Reactions on TiO2 Sorbent Particles with UV Irradiation”, Ind. Engr. Chem. Res., vol. 43 (6), 1411-1417, 2004. Tsai C.J., Chen D., Chein H.M., Chen S.C., Roth J.L., Hsu, Y.D., Li W. and Biswas P., “Theoretical and experimental study of an axial flow cyclone for fine particle removal in vacuum conditions”, J. Aerosol Sci., vol. 35, 1105-1118, 2004. Kulkarni P. and Biswas P., “A Brownian dynamics simulation to predict morphology of nanoparticle deposits in the presence of interparticle interactions”, Aerosol Sci. Technol., vol. 38, 541-554, 2004.