Sol-gel synthesis and characterization of magnetic TiO2 microspheres

Abstract

We tried to prepare magnetic TiO2 microspheres as thermoseeds for hyperthermia of cancer by a solgel process from titanium tetraisopropoxide (TTIP) in a water-in-oil emulsion. The microspheres were prepared by the addition of diethanolamine (DEA) as stabilizer, methanol (CH3OH) as dispersant and colloidal γ-Fe2O3 nanoparticles as origin of magnetization. The γ-Fe2O3 nanoparticles were prepared by an oxidationprecipitation method in FeCl2NaNO 3NaOH system. The diameter of microsphere was controlled by optimizing preparation conditions, i.e., molecular ratio of reactants and stirring speed. Mono-dispersed magnetic TiO2 microspheres 1030μm in diameter were sucessfully obtained by adding a certain amount of water phase with the molar ratio of TTIP/DEA/CH3OH/H2O = 1:1.7:7:22 into kerosene with surfactant (sorbitan monooleate/sorbitan monostearate = 3:1 in weight ratio) 16 wt% of the total amount of oil phase. They contained up to 26.7 wt% γ-Fe2O3 and their saturation magnetization and coercive force were 20.4Am2/kg and 10kA/m, respectively. © 2010 The Ceramic Society of Japan.