Silica coated iron nanoparticles: synthesis, interface control, magnetic and hyperthermia properties

This work provides a detailed study on the synthesis and characterization of silica coated iron nanoparticles (NPs) by coupling Transmission Electronic Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and magnetic measurements. Remarkably, iron NPs (of 9 nm of mean diameter) have been embedd...

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Bibliographic Details
Published in:RSC advances 2018-01, Vol.8 (56), p.32146-32156
Main Authors: Glaria, A, Soulé, S, Hallali, N, Ojo, W.-S, Mirjolet, M, Fuks, G, Cornejo, A, Allouche, J, Dupin, J. C, Martinez, H, Carrey, J, Chaudret, B, Delpech, F, Lachaize, S, Nayral, C
Format: Article
Language:English
Subjects:
Biomedical materials
Chemical Sciences
Chemistry
Ferrofluids
Hyperthermia
Hysteresis loops
Iron
Magnetic measurement
Magnetic permeability
Magnetic properties
Magnetization
Nanoparticles
Remanence
Silicon dioxide
Synthesis
X ray photoelectron spectroscopy
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Summary:This work provides a detailed study on the synthesis and characterization of silica coated iron nanoparticles (NPs) by coupling Transmission Electronic Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and magnetic measurements. Remarkably, iron NPs (of 9 nm of mean diameter) have been embedded in silica without any alteration of the magnetization of the iron cores, thanks to an original protocol of silica coating in non alcoholic medium. Tuning the synthesis parameters (concentration of reactants and choice of solvent), different sizes of Fe@SiO 2 composites can be obtained with different thicknesses of silica. The magnetization of these objects is fully preserved after 24 h of water exposure thanks to a thick (14 nm) silica layer, opening thus new perspectives for biomedical applications. Hyperthermia measurements have been compared between Fe and Fe@SiO 2 NPs, evidencing the self-organization of the free Fe NPs when a large amplitude magnetic field is applied. This phenomenon induces an increase of heating power which is precluded when the Fe cores are immobilised in silica. High-frequency hysteresis loop measurements allowed us to observe for the first time the increase of the ferrofluid susceptibility and remanence which are the signature of the formation of Fe NPs chains. A novel method has been developed for the silica coating of iron nanoparticles while preserving the magnetic properties.
ISSN:2046-2069
2046-2069
DOI:10.1039/c8ra06075d