Authors: W.Y. Teoh, D. Li, C. Selomulya, R. Woodward and R. Amal
Affilation: Monash University, Australia
Pages: 187 - 190
Keywords: flame spray pyrolysis, maghemite nanoparticles, synthesis, characterisation
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.