Literatura científica selecionada sobre o tema "Nanoparticules d'oxyde de fer – Synthèse (chimie)"
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Teses / dissertações sobre o assunto "Nanoparticules d'oxyde de fer – Synthèse (chimie)"
Girardet, Thomas. "Développement de la synthèse micro-ondes de nanoparticules d'oxyde de fer superparamagnétiques pour des applications biomédicales". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0187.
Texto completo da fonteNanomaterials are becoming more and more common in everyday life and in different fields such as the environment for water and soil decontamination, energy storage for batteries or information storage for spintronics. Among the nanomaterials, those with a magnetic character are particularly studied for applications in the biomedical field. Thus, iron oxide nanoparticles are of great scientific interest in the biomedical field because of their biocompatibility, the simplicity of their synthesis and their low cost. Their superparamagnetic properties (no magnetisation at room temperature) allow them to be used for diagnosis (MRI contrast agent), therapy (hyperthermia, vectorisation) or both. During this thesis, the first step was to develop a new method for the synthesis of superparamagnetic functionalized iron oxide nanoparticles that are stable in an aqueous solution: microwave synthesis. To allow an optimised development of this synthesis, an experimental design was carried out. The syntheses were then characterised by different techniques (TEM, DLS, XRD, FTIR, Raman spectroscopy, Mössbauer spectroscopy, TGA, magnetic measurements) to determine their physico-chemical properties as well as possible: the nanoparticles obtained with a diameter between 2.5 and 4 nm are stable in aqueous solutions. In a second step, the biological behaviour of these nanoparticles (cellular internalisation, cytotoxicity, mitochondrial activity) was studied. Then, a study of the relaxivity of the synthesised nanoparticles was carried out in order to be able to compare their effectiveness with that of commercial contrast agents such as Endorem®
Dazzazi, Anass. "Synthèse et caractérisation de nanoparticules d'oxydes métalliques par voie organométallique : vers des applications biomédicales". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/1951/.
Texto completo da fonteThis manuscript describes a collaborative work between the University of Toulouse and the University of Rabat. This work is devoted to the development of metal oxide nanoparticles (gamma-Fe2O3 and ZnO) for biological applications (MRI or optical imaging). It focuses in particular on the development of methodologies for transforming hydrophobic nanoparticles prepared following organometallic chemistry to hydrophilic ones, and to study their properties. Methodologies of solvent exchange to transfer ZnO hydrophobic nanoparticles into water using Gémini ligand have been first developed. The well known "double layer" strategy turned to be much more complicated as expected. The use of amino-PEG surfactants leads to the direct formation of water-dispersible iron oxide nanoparticles. In a second step, the physical properties (optical or magnetic properties) of such nanoparticles were studied either in organic media or in water. In particular, we demonstrated that the optical properties of the ZnO nanoparticles are independent of the solvent but strongly depend on the surface state of the nanoparticles. The first example of a photocommutation of ZnO nanoparticles by a diarylethene photochromic dye has been described. Finally, ZnO nanoparticles stables in buffered solutions have been obtained and the first observation with a fluorescence microscope performed. The iron oxide nanoparticles have been tested as MRI contrast agents
Ait, Kerroum Mohamed Alae. "Synthèse et fonctionnalisation de nano-ferrites pour le traitement par hyperthermie". Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAE016/document.
Texto completo da fonteThe superparamagnetic iron oxide nanoparticles (NPs) are a class of nanomaterials with a high interest in the nanomedicine field. Their magnetic properties and biocompatibility recommend them as potential candidates for diagnostics purposes (MRI, optical or nuclear Imaging ...) and therapy (hyperthermia, nanovectorization...). The aim of this thesis was to study the influence of the synthesis parameters on the final properties of magnetic zinc doped iron oxide nanoparticles. Two synthesis methods were considered, the co-precipitation and the thermal decomposition. The characterization of the obtained nanoparticles by complementary techniques allowed us to propose a consistent relationship between the size, shape and chemical composition on the one hand, and the magnetic properties of the nanoparticles on the other hand. The functionalization of NPs, that is a crucial step for ensuring their biocompatibility and use in magnetic hyperthermia, was also realised and the hyperthermia properties were measured on some typical nanoparticles
Zheng, Ce. "Synthèse de nano-amas d'oxyde métallique par implantation ionique dans un alliage Fe10Cr de haute pureté". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS091/document.
Texto completo da fonteODS (Oxide Dispersed Strengthened) steels, which are reinforced with metal dispersions of nano-oxides (based on Y, Ti and O elements), are promising materials for future nuclear reactors. The detailed understanding of the mechanisms involved in the precipitation of these nano-oxides would improve manufacturing and mechanical properties of these ODS steels, with a strong economic impact for their industrialization. To experimentally study these mechanisms, an analytical approach by ion implantation is used, to control various parameters of synthesis of these precipitates as the temperature and concentration. This study demonstrated the feasibility of this method and concerned the behaviour of alloys models (based on aluminium oxide) under thermal annealing. High purity Fe-10Cr alloys were implanted with Al and O ions at room temperature. Transmission electron microscopy observations showed that the nano-oxides appear in the Fe-10Cr matrix upon ion implantation at room temperature without subsequent annealing. The mobility of implanted elements is caused by the defects created during ion implantation, allowing the nucleation of these nanoparticles, of a few nm in diameter. These nanoparticles are composed of aluminium and oxygen, and also chromium. The high-resolution experiments show that their crystallographic structure is that of a non-equilibrium compound of aluminium oxide (cubic γ-Al₂O₃ type). The heat treatment performed after implantation induces the growth of the nano-sized oxides, and a phase change that tends to balance to the equilibrium structure (hexagonal α-Al₂O₃ type). These results on model alloys are fully applicable to industrial materials: indeed ion implantation reproduces the conditions of milling and heat treatments are at equivalent temperatures to those of thermo-mechanical treatments. A mechanism involving the precipitation of nano-oxide dispersed in ODS alloys is proposed in this manuscript based on the obtained experimental results, and the existing literature
Kombaya, Touckia Linin Erland Modeste. "Conception, élaboration et caractérisation d’emballages actifs absorbeurs d’O2". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG006.
Texto completo da fonteCurrently, we are seeing the development of new materials, namely active materials, through various processes and applications. Among these active materials, the use of O2 scavenging iron nanoparticles (NanoFe) as required knowledge of several parameters for efficient application in the field of food packaging such as knowledge about oxidation mechanism and O2 consumption rate. These parameters are necessary to be able to quantify the absorption capacity and absorption rate of O2. Although necessary, these two parameters have so far been little characterized and even less related to the morphological (size, specific surface, etc.) and physico-chemical properties (such as the iron speciation) of iron nanoparticles implemented.In order to tailor nanocomposite film with O2 scavenging properties, this work aims to combine a passive barrier, related to the phenomenon of tortuosity induced by the presence of clay platelets dispersed in a polymeric matrix and an active barrier, related to oxygen uptake by synthesized NanoFe. Nano-Fe were synthesized by chemical reduction with sodium borohydride on Montmorillonite clay (MMT) support. The TEM characterization revealed the formation of iron nanoparticle aggregates with an average size of 57 ± 17 nm scattered on the MMT surface. The Mössbauer kinetics on the MMT-Fe powder confirms that the different iron phases (Fe0 and FeII) in the iron nanoparticles do not oxidize at the same speed. This allowed to adjust the mathematical model of O2 absorption properties prediction. The study of O2 absorption properties on powders has shown that the reaction constant (k), the proportionality coefficient (n) and the O2 absorption capacities are of the same order of magnitude for the wet, dried and stored powders. The nanocomposite films prepared from the synthesized MMT-Fe dried powders incorporated in a LLDPE polymer showed good absorption capacity, but lower than that of the fresh powder, related to the advanced oxidation of iron in these films, confirmed by Mössbauer spectroscopy (films are 60% oxidized versus 30% for powders). A numerical model using the second law of Fick coupled to the system of chemical kinetics equations obtained on the powder, made it possible to predict the phenomenon of diffusion and reaction of oxygen in films produced. This model was compared with experimental data obtained by measuring O2 absorption by films. In parallel, a study of the absorption kinetics of commercial O2 scavengers, commonly used in modified atmosphere packaging, was carried out. On these commercial systems, absorption kinetics has also been described by a second-order kinetic reaction with Arrhenius-like behavior for the effect of temperature. Mössbauer spectroscopy revealed that, in this case, only the Fe0 species were predominant to describe the kinetics (that of FeII being negligible as it was fast). We have shown for the first time that Mössbauer spectroscopy can be successfully coupled to the measurement of oxygen in order to characterize iron oxidation, speciation and O2 absorption capacity in situ. This configuration associating Mössbauer spectroscopy and oxygen measurement provided valuable information on the reaction mechanisms governing the O2 absorbers. All of these results will have important implications for understanding oxygen uptake in the active O2 absorber system
Bergeron, Benjamin. "Synthèse de nanoparticules à structure coeur-coquille d'oxyde de fer et d'or". Master's thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25564.
Texto completo da fonteDaou, Toufic Jean. "Synthèse et fonctionnalisation de nanoparticules d’oxydes de fer magnétiques". Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/DAOU_Toufic_Jean_2007.pdf.
Texto completo da fonteIn the first part, magnetite nanoparticles with controlled size have been synthesized by co-precipitation followed by hydrothermal treatment. By varying different parameters like the pH, the nature of the bases and the Base/Fe ratio, we were able to obtain, nanoparticles with an average size of 12 (± 2) nm but especially of 39 (± 5) nm with global composition: Fe2. 95O4 which can be described by a core-shell system with stoechiometric magnetite as core and oxidized layer as shell. In the second part, we report, our results on the direct and strong bonding of functional organic molecules onto the surface of this nanoparticles using either phosphate, phosphonate or carboxylate groups as coupling agents. These studies have shown that the nanoparticles functionalised by a phosphate or phosphonate groups allowed stronger bonding on the surface of the nanoparticles, higher grafting rate than the carboxylate groups and especially the conservation of the magnetic properties. The grafting occurs mainly by interaction with the Fe3+ in octahedral sites present in the (111) denser plane. The magnetic properties are not modified with phosphonate and phosphate, whereas the carboxylate induce a canting of spin in the oxidized layer decreasing magnetization. Optimisation of grafting conditions has conducted to very stable suspensions in water and THF
Vichery, Charlotte. "Procédé de recuit protégé appliqué à des nanoparticules d'oxyde de fer : étude des relations structure / propriétés magnétiques". Phd thesis, Palaiseau, Ecole polytechnique, 2012. https://pastel.hal.science/docs/00/75/65/67/PDF/VICHERY_these.pdf.
Texto completo da fonteBecause of their promising applications, particularly in the field of biomedicine, many research activities are currently focused in understanding and improving the magnetic properties of iron oxide nanoparticles. The large surface/volume ratio, inherent to the size reduction at the nanometer scale, and crystalline defects have a significant influence on the magnetic properties of these particles, because they give rise to weakly coupled and misaligned spins, which are responsible for low saturation magnetization values. In the course of this PhD project, a strategy of protected annealing was investigated to improve the crystallinity and/or to change the local composition of maghemite and cobalt ferrite nanoparticles, without agglomeration or grain growth. A diamagnetic, refractory and inert sol-gel silica matrix was selected. The high-temperature annealing of the composite samples was first used to study the impact of various structural defects on the magnetic properties. We showed that for maghemite nanoparticles, ordering of Fe vacancies and changes in the surface state, as a result of dehydration, had opposite effects. Vacancy ordering predominates for particles of 14 nm and tends to increase magnetization values, while the removal of surface hydroxyl groups, predominant for particles of 7 nm, induces the propagation of the outer shell made of misaligned spins toward the center of the particles, thus decreasing magnetization values. In the case of cobalt ferrite, the Co-Fe ions distribution may also have an impact on spin misalignment. However, an 800°C annealing did not induced a large increase in inversion degree, probably because of the refractory nature of CoFe2O4. This strategy of protected annealing also allowed modulating the magnetic properties of maghemite particles upon cobalt doping. A progressive increase of the anisotropy constant, up to 3. 5 times, was observed as a result of the diffusion of Co2+ ions into the spinel structure
Vichery, Charlotte. "Procédé de recuit protégé appliqué à des nanoparticules d'oxyde de fer : étude des relations structure / propriétés magnétiques". Phd thesis, Ecole Polytechnique X, 2012. http://pastel.archives-ouvertes.fr/pastel-00756567.
Texto completo da fonteKovalenko, Artem. "Stabilisation de microbulles de gaz par des tensioactifs semi-fluorés et des nanoparticules d'oxyde de fer". Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01037952.
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