Simultaneous formation of ferrite nanocrystals and deposition of thin films via a microwave-assisted nonaqueous sol-gel process

Combination of the surfactant-free nonaqueous sol-gel approach with the microwave technique makes it possible to synthesize Fe3O4, CoFe2O4, MnFe2O4, and NiFe2O4 nanoparticles of about 5-6nm and with high crystallinity and good morphological uniformity. The synthesis involves the reaction of metal acetates or acetylacetonates as precursors with benzyl alcohol at 170°C under microwave irradiation of 12min. Immersion of glass substrates in the reaction solution results in the deposition of homogeneous metal ferrite films whose thickness can be adjusted through the precursor concentration. If preformed nickel nanoparticles are used as a type of curved substrate, the ferrite nanoparticles coat the seeds and form core-shell structures. These results extend the microwave-assisted nonaqueous sol-gel approach beyond the simple synthesis of nanoparticles to the preparation of thin films on flat or curved substrate

Microwave-Assisted Nonaqueous Sol–Gel Deposition of Different Spinel Ferrites and Barium Titanate Perovskite Thin Films

Rapid and selective heating of solvents by microwave irradiation coupled to nonaqueous sol–gel chemistry makes it possible to simultaneously synthesize metal oxide nanoparticles within minutes and deposit them on substrates. The simple immersion of substrates, such as glass slides, in the reaction solution results after microwave heating in the deposition of homogeneous porous thin films whose thickness can be adjusted through the precursor concentration. Here we use such a microwave-assisted nonaqueous sol–gel process for the formation of various spinel ferrite MFe2O4 (M = Fe, Co, Mn, Ni) and BaTiO3 nanoparticles and their deposition as thin films. The approach offers high flexibility with respect to controlling the crystal size by adjusting the reaction time and/or temperature. Based on the example of CoFe2O4 nanoparticles, we show how the crystal size can carefully be tuned from 4 to 8 nm, resulting in a continuous change of the magnetic properties

Simultaneous formation of ferrite nanocrystals and deposition of thin films via a microwave-assisted nonaqueous sol-gel process

Combination of the surfactant-free nonaqueous sol-gel approach with the microwave technique makes it possible to synthesize Fe3O4, CoFe2O4, MnFe2O4, and NiFe 2O4 nanoparticles of about 5-6 nm and with high crystallinity and good morphological uniformity. The synthesis involves the reaction of metal acetates or acetylacetonates as precursors with benzyl alcohol at 170 °C under microwave irradiation of 12 min. Immersion of glass substrates in the reaction solution results in the deposition of homogeneous metal ferrite films whose thickness can be adjusted through the precursor concentration. If preformed nickel nanoparticles are used as a type of curved substrate, the ferrite nanoparticles coat the seeds and form core-shell structures. These results extend the microwave-assisted nonaqueous sol-gel approach beyond the simple synthesis of nanoparticles to the preparation of thin films on flat or curved substrates. © 2010 Springer Science+Business Media, LLC

Double role of polyethylene glycol in the microwaves-assisted non-hydrolytic synthesis of nanometric TiO2: oxygen source and stabilizing agent

The microwaves-assisted reaction between titanium(IV) tetrachloride and polyethylene glycol (PEG) represents a novel non-aqueous sol–gel route for synthesizing surface-stabilized titanium dioxide nanoparticles. X-ray powder diffraction measurements showed the exclusive presence of anatase phase. Transmission electron microscopy investigations revealed that the particles are nearly uniform in shape with sizes ranging from 4 to 8 nm and a low degree of agglomeration. The presence of covalently bonded PEG chains on the particles surface has been shown by Fourier transform infrared (FT-IR) spectroscopy. This surface functionalization greatly enhances the dispersibility of the particles in water, as observed by dynamic light scattering and zeta-potential analyses. Furthermore, the investigation of the reaction by-products by a combination of FT-IR and high-performance liquid chromatography (HPLC-Mass) techniques allowed a deeper insight into the reactionmechanism suggesting a double role of PEG as a stabilizing agent and an oxygen source

Simultaneous formation of ferrite nanocrystals and deposition of thin films via a microwave-assisted nonaqueous sol–gel process

ISSN:0928-0707ISSN:1573-484