Synthesis and Characterization of Ferromagnetic Polymer-Coated Cobalt Nanoparticles in Multi-Gram Quantities PDF Download
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Author: Sarah Grace Rasmussen Publisher: ISBN: Category : Languages : en Pages : 200
Book Description
ABSTRACTFerromagnetic cobalt nanoparticles (CoNPs) are of interest due to their inherent dipolar properties which enable one-dimensional (1-D) nanoparticle self-assembly. As their magnetic properties change drastically with their size, the ability to selectively synthesize monodisperse metallic nanoparticles of varying diameters remains a crucial challenge. Although there have been extensive studies performed on various metallic nanoparticles yielding superparamagnetic materials (such as Fe3O4, Fe2O3, Co metals), research concerning the synthesis of ferromagnetic materials has only recently resurged within the last 20 years. In this work, methods for the synthesis of ferromagnetic cobalt nanoparticles on multi-gram scales were investigated. A one-pot synthetic method which produced up to 4 grams of cobalt nanoparticles per reaction was developed, and it was also found that this reaction had a direct correlation with particle size and reaction temperature, allowing for the large-scale synthesis of polystyrene-coated cobalt nanoparticles of pre-selected diameters.
Author: Sarah Grace Rasmussen Publisher: ISBN: Category : Languages : en Pages : 200
Book Description
ABSTRACTFerromagnetic cobalt nanoparticles (CoNPs) are of interest due to their inherent dipolar properties which enable one-dimensional (1-D) nanoparticle self-assembly. As their magnetic properties change drastically with their size, the ability to selectively synthesize monodisperse metallic nanoparticles of varying diameters remains a crucial challenge. Although there have been extensive studies performed on various metallic nanoparticles yielding superparamagnetic materials (such as Fe3O4, Fe2O3, Co metals), research concerning the synthesis of ferromagnetic materials has only recently resurged within the last 20 years. In this work, methods for the synthesis of ferromagnetic cobalt nanoparticles on multi-gram scales were investigated. A one-pot synthetic method which produced up to 4 grams of cobalt nanoparticles per reaction was developed, and it was also found that this reaction had a direct correlation with particle size and reaction temperature, allowing for the large-scale synthesis of polystyrene-coated cobalt nanoparticles of pre-selected diameters.
Author: Mehdi Zamanpour Publisher: ISBN: Category : Energy storage Languages : en Pages : 134
Book Description
The ever-increasing desire for more energy attainable from a smaller volume of matter has driven researchers to explore advanced materials at the molecular size. Magnetic materials at the nanometer size scale have been the subject of enormous research effort worldwide for more than half a century. Different magnetic nanoparticles have shown different behavior in the absence and presence of an external magnetic field, which has led them to be categorized as soft or hard magnets. Applications range from medical and biomedical devices to magnetic recording media and magnetic sensing have emphasized the importance of this class of materials. Soft magnetic phases have found application in power generation and magnetic targeted drug delivery, while hard magnets have been subject of extensive research for application as energy storage media. Discovery of the exchange-coupling phenomenon between two adjacent hard and soft magnetic phases has attracted scientists to develop advanced materials for energy storage with no usage of fossil fuels: clean energy. In this Dissertation, synthesis of pure phase, soft FeCo nanoparticles with high magnetic moment and hard phase CoxC nanoparticles possessing high coercivity is reported. The polyol method (chemical co-precipitating at polyhydric alcohol as reducing agent) is used to make FeCo and CoxC nanoparticles and the effects of important reaction kinetics parameters on the structure and magnetic properties of the products are studied. Careful analysis of correlations between these parameters and the properties of the magnetic particles has made synthesis of FeCo and CoxC nanoparticles with desired properties possible. Fabrication of MnAlC-FeCo heterostructures as a rare earth-free alternative for high-performance permanent magnet is also reported. To synthesize MnAlC-FeCo, mechanical alloying and dry mixing of MnAlC and FeCo nanoparticles are accomplished followed by annealing in a furnace. Overall, the achieved results in this work enable synthesis of high moment FeCo and high coercivity CoxC with desired structure and magnetic properties obtained through polyol method. In particular, this Dissertation provides the technique to fabricate cobalt carbide nanoparticles without using rare earth elements as a catalyst or as heterogeneous seed nuclei at any stage of the processing.
Author: Zachary John Huba Publisher: ISBN: Category : Chemistry, Inorganic Languages : en Pages : 156
Book Description
Permanent magnets are used heavily for multiple applications in industry and current electronic technologies. However, the current permanent landscape is muddled by high cost of materials and insufficient magnetic or thermal properties. The primary focus of this dissertation work is the synthesis and optimization of a new permanent magnetic material, in the form of cobalt carbide nanomaterials. The optimization revolved around controlling the crystal phase and particle shape of synthesized cobalt carbide particles; these parameters have significant impact on the observed magnetic properties of magnetic nanoparticles. Co3C was identified to be the preferred crystal phase, leading to better magnetic properties. Cobalt Fumarate was found to be the ideal precursor to synthesize anisotropic Co3C particles and enhance magnetic properties of the synthesized cobalt carbide particles. Lastly, an ethanol based reduction system was employed to develop the greener synthesis of Co and Ni magnetic particles.
Author: Hari Lal Bhatta Publisher: ISBN: Category : Cobalt Languages : en Pages : 102
Book Description
Nanomaterial research has attracted a great deal of enthusiasm from the public because of the applications of nanomaterials in various areas of science such as physics, chemistry, medicine, and materials science. Biocompatible and nontoxic cobalt nanoparticles have biomedical applications including drug delivery, cell and deoxyribonucleic acid (DNA) separation, gene cloning, and magnetic resonance imaging. The main aim of this research project is to produce contamination-free cobalt nanoparticles for biomedical applications. Pulsed Laser Deposition (PLD) technique was used to fabricate contamination-free cobalt nanoparticles directly from cobalt foil. A KrF laser having laser pulses of wavelength 248 nm, pulse duration of 20 ns, and repetition rate of 10 Hz was employed in pulsed laser deposition technique. The synthesized cobalt nanoparticles were characterized using UV-Vis absorption spectroscopy and dynamic laser light scattering (DLLS). The synthesized cobalt nanoparticles were stabilized in glucose solutions of various concentrations. The UV-Vis absorption peak around 268 nm confirms the presence of cobalt nanoparticles in aqueous media. The DLLS size distribution of cobalt nanoparticles has been found in the range between 355 nm to 465 nm with variation of growth parameters such as laser energy, number of shot, and glucose concentration. Glucose stabilized cobalt nanoparticles have been successfully functionalized with DNA and laser modified DNA. The binding of cobalt nanoparticles with DNA plays an important role in the future for gene delivery.
Author: Sasha Lenore Gill-Ljunghammer Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
As electronic devices become more integrated in everyday life, there is an increasing necessity for miniaturization with exceptional efficiency. The use of tunable magnetic materials for information storage and transfer can meet this demand with many significant advantages over current technologies. The implementation of this science is contingent on optimizing the voltage control of magnetism (VCM), which has additional applications in healthcare and sensing. This work seeks to improve VCM in multiferroic composites and magnetoioics. In chapter 3 of this thesis, we report a straightforward and scalable synthesis of superparamagnetic cobalt ferrite nanoparticles that allows for precise size selection. The particles produced via this route also have remarkable size and shape uniformity, making them ideal for use in a strain-mediated multiferroic composite. In chapter 4 we advance fundamental understanding toward achieving unprecedented magnetic control in nanostructured Sm-Co magnets via electrochemical hydrogen charging. The structural and magnetic properties of SmCo5 and Sm2Co17, as well as the kinetics and thermodynamics involved in their hydrogenation, are documented for future work. Oxidation in air and in electrolyte is identified as a key challenge.
Author: Li Tan Publisher: ISBN: Category : Languages : en Pages :
Book Description
This thesis mainly covers the synthesis, surface modification, magnetic-field-induced assembly and thermo-responsive functionalization of superparamagnetic Co NPs initially stabilized by hydrophobic small molecules oleic acid (OA) and trioctylphosphine oxide (TOPO), as well as the synthesis of both superparamagnetic and ferromagnetic Co NPs by using end-functionalized-polystyrene as stabilizer. Co NPs, due to their excellent magnetic and catalytic properties, have great potential application in various fields, such as ferrofluids, catalysis, and magnetic resonance imaging (MRI). Superparamagnetic Co NPs are especially interesting, since they exhibit zero coercivity. They get magnetized in an external magnetic field and reach their saturation magnetization rapidly, but no magnetic moment remains after removal of the applied magnetic field. [...]
Author: Sarah Grace Rasmussen
Author: Sarah Grace Rasmussen
Author: 
Author: Mehdi Zamanpour
Author: Mashavhela Manuel
Author: Zachary John Huba
Author: Hari Lal Bhatta
Author: Sasha Lenore Gill-Ljunghammer
Author: Haiza Haroon
Author: Li Tan
Author: S. Stephen Papell