Metal oxide Nanostructures from Electrospun Carbon Templates ab 79 € als Taschenbuch: Metal Oxide Nanofibers and Nanotubes. Aus dem Bereich: Bücher, Wissenschaft, Chemie,
Metal oxide Nanostructures from Electrospun Carbon Templates ab 79 EURO Metal Oxide Nanofibers and Nanotubes
This book is comprised of five Chapters. It underwrites literature review and background of nanomaterials (nanowires) indicates that materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties and also gives statistics of their applications such as, to produce low cost flexible solar panels, describes their part in the development of biomedical sensors and biochips, hydrogen sensors, optoelectronics, reduce the cost of producing fuel cells, and to make dense computer memory, called "race track memory. We included the detailed experimental procedure for preparation of porous anodic alumina oxide (AAO) templates and Direct current (DC) electrodeposition technique, Mechanism for formation of fcc-cobalt nanowires in electrodeposition at ambient temperature, Influence of bath temperature and pH on structure of electrodeposited cobalt nanowires is presented briefly, and at the end we presented summary of conclusions for the experimental research work and recommendations for proposed future works.
The present work deals with the preparation of mesoporous metal oxide systems by means of new block copolymer templates and the development of original structural characterization methods. In the first part of the work is shown that PIB-PEO block copolymers generate robust and highly porous metal oxide textures characterized by large pores of spherical form. Sol-gel mesoporous TiO2 films were also tested as semiconductors in dye sensitized solar cell devices noticing promising results in comparison with the nanoparticulate systems. Furthermore, the remarkable templating behavior of the PIB-PEO block copolymers is also presented by the preparation of hierarchical silica powders. Due to the structural complexity of these latter systems their characterization could not be exhaustively carried out by means of standard analysis approaches. The employment of the in-situ SAXS/SANS-physisorption technique provided thus an exclusive possibility to study in detail the porosity and its organization in these hierarchical materials. Interesting applications of this novel characterization technique are given also by the analysis of further systems like periodic mesoporous organosilicas (PMOs).
The research is significant with regards to the understanding of the physics of iron oxide (IO) nanoparticles and graphene-IO composites and their applications in medicine. The effect of nucleation and growth of Fe3O4/Gamma-Fe2O3 nanocrystals within biomolecular templates, on the magneto-structural properties and their implications in MRI contrast and heat generation in magnetic hyperthermia has been extensively studied. The research tries to address the issues relating to the uniformity in particle size, shape, distribution, and effective functionalization. By choosing different templates the mutual interaction between adjacent particles could be tuned which was found to have a profound impact on the magnetic anisotropy of such systems. Future work would concentrate on the self assembly of such systems whereby the anisotropy can or is expected to be modulated to achieve enhanced diagnostic and therapeutic value in killing cancer cells. The work follows an integrated approach and covers the entire spectrum of materials development (synthesis by mimicking nature-biomineralization), applications (MRI and magnetic hyperthermia) and simulation (bioheat model using COMSOL).
One-dimensional nanostructures are of great interest because of their potential application in many areas, such as high-density perpendicular magnetic recording media and nanosensors. The synthesis and precise control of such a magnetic nanostructure on a large scale is a challenging issue in material science. One strategy is to electrode posit magnetic nanowires into nanochannels of porous anodic aluminum oxide (AAO) templates. In this work we focused on Fe-nanowire arrays with diameters of about 30 nm, using the shape anisotropy and the crystalline anisotropy. In the present paper, we report a unique dynamically controlled growth method to prepare Fe nanowire with preferred (110) orientation along the wire. The effects of pH, symmetry/asymmetry electrodeposition voltage and frequency on magnetic properties of nenowires were investigated. Computing the samples magnetization proved that by increasing the non symmetric voltage, magnetization of nanowires increased. On the other hand, the values of coercive field and squareness of samples showed that 1000 Hz is the optimum system frequency which reveals special properties of Fe nanowires discussed in this book.
Anodized Aluminum Oxide (AAO) nano-templates were made through two step anodization process of aluminum sheet in two electrodes electrochemical cell. Controlling of the structural properties of pores template achieved by a fine adjusting of some parameters of the electrochemical process includes, type, concentration, and temperature. Then the fabricated nano-template subjected to post electrodeposition of nanometalic substances of , Ag ,Au, Cu, and Pt from their freshly prepared salts ligand complexes. All prepared templates were subjected to intensive surface structure analysis by AFM, SEM, and XRD a detailed information on pore shape , pore size distribution , and crystal types were estimated .
The work covered herein discusses for the first time various techniques used in the fabrication of metal oxide nanofibers and nanotubes from eletrospun carbon fibers as templates. The nanofibers were prepared by electrospinning metal oxide precursor inside a polymer matrix. The metal oxide tubes were by tubes by fiber templating. This was followed by calcination to yield the nanofibers and nanotubes. Their morphological, structural, optoelectronic and catalytic properties are also discussed. Among key applications they have found utilization as catalyst supports. Palladium nanoparticles have been supported on Titanium dioxide nanofibers and applied in Heck-coupling reactions. Similarly, included is the effect of impurities on the metal oxide tubes properties done by doping with metal ions. In addition, photocatalytic behavior of metal oxides nanofibers have also been discussed.
Block copolymers are fascinating materials that have attracted a lot of attention in recent years, as a consequence of their ability to serve as ideal building blocks to fabricate nanostructures. They are macromolecules consisting of chemically different parts (blocks) that tend to self-assembly into well-ordered nanoscaled structures both in bulk and in a selective solvent for one of the block. In this thesis, amphiphilic block copolymers were successfully applied as templates for the controlled formation and defined positioning of metal and metal oxide nanoparticles arranged in periodic patterns on flat surfaces and in polymer nanofibre structures. Furthermore, a method was developed to arrange nanoparticles in desired nano-structured micropatterns on flat substrates using the combinations of "top_down" and "bottom-up" approaches: a self-assembled monolayer of hexagonally ordered block copolymer micelles loaded with gold precursor salt was used as a resist for lithography. Two diffrent energy sources were applied to selectively modify and pin the micelles to the substrate: UV light and s Focus Ion Beam.