Synthesis And Characterization Of High Quality Iron Oxide Nanoparticles Of Controlled Size Shape And Magnetic Properties

The work in this thesis has been focused on the fabrication and characterization of iron based nanoparticles with controlled size and morphology with the aim: (i) to investigate their properties for potential applications in MICR toners and biomedical field and (ii) to study finite size effects on the magnetic properties of the nanoparticles. For the biomedical applications, core/shell structured iron/iron-oxide and hollow shell nanoparticles were synthesized by thermal decomposition of iron organometallic compounds [Fe(CO) 5] at high temperature. Core/shell structured iron/iron-oxide nanoparticles have been prepared in the presence of oleic acid and oleylamine. Particle size and composition was controlled by varying the reaction parameters during synthesis. The as-made particles are hydrophobic and not dispersible in water. Water dispersibility was achieved by ligand exchange a with double hydrophilic diblock copolymer. Relaxometery measurements of the transverse relaxation time T 2 of the nanoparticles solution at 3 Tesla confirm that the core/shell nanoparticles are an excellent MRI contrast agent using T 2 weighted imaging sequences. In comparison to conventionally used iron oxide nanoparticles, iron/iron-oxide core/shell nanoparticles offer four times stronger T 2 shortening effect at comparable core size due to their higher magnetization. The magnetic properties were studied as a function of particle size, composition and morphology. Hollow nanostructures are composed of randomly oriented grains arranged together to make a shell layer and make an interesting class of materials. The hollow morphology can be used as an extra degree of freedom to control the magnetic properties. Owing to their hollow morphology, they can be used for the targeted drug delivery applications by filling the drug inside their cavity. For the magnetic toners applications, particles were synthesized by chemically reducing iron salt using sodium borohydride and then coated with polyethylene glycol. Parameters such as the reactant concentrations and their flow rate were varied to study the effect of particle size, structure and crystallinity on the magnetic nanoparticles. Many different hydrophilic surfactants and polymers electrolytes were investigated for the particles' stability in water. PSSNa was found to be the best coating agent among all the other investigated polymer and surfactants for particles stability in water. Particles have an average size of 50 nm and magnetization above 150 emu/g. It is anticipated that owing to their high saturation magnetization and magneto crystalline anisotropy, the incorporations of PSSNa coated nanoparticles into the MICR toner can reduce the pigment loading and hence optimize the toner quality. The magnetic properties were studied as a function of particle size, composition and morphology. The saturation magnetization and coercivity was found to be strongly dependent on the particle size and morphology. The estimated effective anisotropy of the particles was found to be much higher than their bulk values because of their morphology and finite size effects. Core/shell particles below an average size of 12 nm display superparamagnetism and exchange bias phenomenon. The hollow morphology can be used as an extra degree of freedom to control magnetic properties. The enormously large number of pinned spins at the inner and outer surface and at the interface between the grain boundaries in hollow nanoparticles, gives rise to a very large value of effective anisotropy in these nanoparticles and measured hyteresis loops are minor loops. The surface spin disorder contribution to magnetic behavior is strongly influenced by the cooling field magnitude.

Timely information on scientific and engineering developments occurring in laboratories around the world provides critical input to maintaining the economic and technological strength of the United States. Moreover, sharing this information quickly with other countries can greatly enhance the productivity of scientists and engineers. These are some of the reasons why the National Science Foundation (NSF) has been involved in funding science and technology assessments comparing the United States and foreign countries since the early 1980s. A substantial number of these studies have been conducted by the World Technology Evaluation Center (WTEC) managed by Loyola College through a cooperative agreement with NSF. The National Science and Technology Council (NSTC), Committee on Technology's Interagency Working Group on NanoScience, Engineering and Technology (CT/IWGN) worked with WTEC to develop the scope of this Nanostucture Science and Technology report in an effort to develop a baseline of understanding for how to strategically make Federal nanoscale R&D investments in the coming years. The purpose of the NSTC/WTEC activity is to assess R&D efforts in other countries in specific areas of technology, to compare these efforts and their results to U. S. research in the same areas, and to identify opportunities for international collaboration in precompetitive research. Many U. S. organizations support substantial data gathering and analysis efforts focusing on nations such as Japan. But often the results of these studies are not widely available. At the same time, government and privately sponsored studies that are in the public domain tend to be "input" studies.

Nanotechnology is the application of science to control matter at the molecular level. It has become one of the most promising applied technologies in all areas of science. Nanoparticles have multi-functional properties and have created very interesting applications in various fields such as medicine, nutrition, bioenergy, agriculture and the environment. But the biogenic syntheses of monodispersed nanoparticles with specific sizes and shapes have been a challenge in biomaterial science. Nanoparticles are of great interest due to their extremely small size and large surface-to-volume ratio, which lead to both chemical and physical differences in their properties (e.g., mechanical properties, biological and sterical properties, catalytic activity, thermal and electrical conductivity, optical absorption and melting point) compared to bulk of the same chemical composition. Recently, however, synthesizing metal nanoparticles using green technology via microorganisms, plants, viruses, and so on, has been extensively studied and has become recognized as a green and efficient way for further exploiting biological systems as convenient nanofactories. Thus the biological synthesis of nanoparticles is increasingly regarded as a rapid, ecofriendly, and easily scaled-up technology. Today researchers are developing new techniques and materials using nanotechnology that may be suitable for plants to boost their native functions. Recently, biological nanoparticles were found to be more pharmacologically active than physico-chemically synthesized nanoparticles. Various applications of biosynthesized nanoparticles have been discovered, especially in the field of biomedical research, such as applications to specific delivery of drugs, use for tumor detection, angiogenesis, genetic disease and genetic disorder diagnosis, photoimaging, and photothermal therapy. Further, iron oxide nanoparticles have been applied to cancer therapy, hyperthermia, drug delivery, tissue repair, cell labeling, targeting and immunoassays, detoxification of biological fluids, magnetic resonance imaging, and magnetically responsive drug delivery therapy. Nanoparticle synthesis for plant byproducts for biomedical applications has vast potential. This book offers researchers in plant science and biomedicine the latest research and opportunity to develop new tools for the synthesis of environmentally friendly and cost-effective nanoparticles for applications in biomedicine as well as other various fields.

Metal Oxide Nanoparticles in Organic Solvents discusses recent advances in the chemistry involved for the controlled synthesis and assembly of metal oxide nanoparticles, the characterizations required by such nanoobjects, and their size and shape depending properties. In the last few years, a valuable alternative to the well-known aqueous sol-gel processes was developed in the form of nonaqueous solution routes. Metal Oxide Nanoparticles in Organic Solvents reviews and compares surfactant- and solvent-controlled routes, as well as providing an overview of techniques for the characterization of metal oxide nanoparticles, crystallization pathways, the physical properties of metal oxide nanoparticles, their applications in diverse fields of technology, and their assembly into larger nano- and mesostructures. Researchers and postgraduates in the fields of nanomaterials and sol-gel chemistry will appreciate this book’s informative approach to chemical formation mechanisms in relation to metal oxides.

Magnetic nanomaterials have attracted great interest in recent years due to their promising properties for biomedical and energy applications. In this research, the synthesis of iron-based magnetic nanoparticles has been investigated. Highly monodispersed iron oxide nanoparticles (magnetite and wüstite) have been synthesized by using the thermal decomposition approach. By using FeO(OH) or Fe(oleate)3 as iron precursor, 1-octadecene as solvent and oleic acid as surfactant, spherical iron oxide nanoparticles with an average diameter of 5 to 30 nm could be prepared. Moreover, FePt nanowires/rods with different length and tetrapods were synthesized by reduction of Pt(acac)2 and decomposition of Fe(CO)5 or Fe(acac)3 as well. In order to transfer iron oxide nanoparticles and FePt nanoparticles into the water phase, a modified silane-coating method was developed by using 3-(triethoxysilyl)propyl succinic anhydride as ligand in basic solution, iron oxide nanoparticles and FePt nanowires could be easily transferred into water.

MODERN FERRITES, Volume 1 A robust exploration of the basic principles of ferrimagnetics and their applications In Modern Ferrites Volume 1: Basic Principles, Processing and Properties, renowned researcher and educator Vincent G. Harris delivers a comprehensive overview of the basic principles and ferrimagnetic phenomena of modern ferrite materials. Volume 1 explores the fundamental properties of ferrite systems, including their structure, chemistry, and magnetism; the latest in processing methodologies; and the unique properties that result. The authors explore the processing, structure, and property relationships in ferrites as nanoparticles, thin and thick films, compacts, and crystals and how these relationships are key to realizing practical device applications laying the foundation for next generation technologies. This volume also includes: Comprehensive investigation of the historical and scientific significance of ferrites upon ancient and modern societies; Neel’s expanded theory of molecular field magnetism applied to ferrimagnetic oxides together with theoretic advances in density functional theory; Nonlinear excitations in ferrite systems and their potential for device technologies; Practical discussions of nanoparticle, thin, and thick film growth techniques; Ferrite-based electronic band-gap heterostructures and metamaterials. Perfect for RF engineers and magnetitians working in the field of RF electronics, radar, communications, and spintronics as well as other emerging technologies. Modern Ferrites will earn a place on the bookshelves of engineers and scientists interested in the ever-expanding technologies reliant upon ferrite materials and new processing methodologies. Modern Ferrites Volume 2: Emerging Technologies and Applications is also available (ISBN: 9781394156139).

Iron Oxide Nanoparticles for Biomedical Applications: Synthesis, Functionalization and Application begins with several chapters covering the synthesis, stabilization, physico-chemical characterization and functionalization of iron oxide nanoparticles. The second part of the book outlines the various biomedical imaging applications that currently take advantage of the magnetic properties of iron oxide nanoparticles. Brief attention is given to potential iron oxide based therapies, while the final chapter covers nanocytotoxicity, which is a key concern wherever exposure to nanomaterials might occur. This comprehensive book is an essential reference for all those academics and professionals who require thorough knowledge of recent and future developments in the role of iron oxide nanoparticles in biomedicine. Unlocks the potential of iron oxide nanoparticles to transform diagnostic imaging techniques Contains full coverage of new developments and recent research, making this essential reading for researchers and engineers alike Explains the synthesis, processing and characterization of iron oxide nanoparticles with a view to their use in biomedicine

Written by an international team of editors and contributors from renowned universities and institutes, this book addresses the latest research in the field of nanobiomaterials, covering nanotechnologies for their fabrication, developments in biomedical applications, and the challenges of biosafety in clinic uses. Clearly structured, the volume defines the scope and classification of the field, resulting in a broad overview from fundamental principles to current technological advances, and from materials synthesis to biomedical applications along with future trends.