Synthesis and characterisation of flame-sprayed superparamagnetic bare and silica-coated maghemite nanoparticles

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Magnetic nanoparticles are a much sought-after entity with direct applications in bioseparation, magnetic resonance imaging (MRI), drug delivery and cancer therapy. gamma-Fe2O3 and SiO2/ gamma-Fe2O3 nanoparticles of different sizes (dBET = 5-50 nm) were synthesised via the rapid Flame Spray Pyrolysis technique. Transmission electron microscopy (TEM) of bare gamma-Fe2O3 shows unique hexagonal disc-shaped nanoparticles. Different morphologies of SiO2/ gamma-Fe2O3 were obtained by varying the Fe to Si composition. At Fe:Si ratio of 1:2, gamma-Fe2O3 phase was visibly segregated to the edge of discrete silica particles, while well-dispersed multi-cores gamma-Fe2O3 embedded in spherical silica particles were observed at Fe:Si ratio of 1:5. Quantitative analysis on the shape and structure of these nanoparticles was conducted using characterisation techniques including TEM, X-ray diffraction (XRD), N2 adsorption, and SQUID. The gamma-Fe2O3 particles were found to exhibit predominantly superparamagnetic behaviour, with saturation magnetization values comparable to bulk maghemite, with reduced levels shown by the SiO2/ gamma-Fe2O3 nanoparticles. The study demonstrated the possibility of tailoring and optimizing the properties of magnetic nanoparticles to suit their specific applications.

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Journal: TechConnect Briefs
Volume: 4, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 4
Published: May 20, 2007
Pages: 187 - 190
Industry sector: Advanced Materials & Manufacturing
Topic: Nanoparticle Synthesis & Applications
ISBN: 1-4200-6376-6