Nanofiber metal oxide

Application of transmission electron microscopy (TEM) techniques on heterogeneous catalysis covers a wide range of solid catalysts, including supported metal particles, transition metal oxides, zeolites and carbon nanotubes and nanofibers etc. 

The polymer resulting from oxidation of 3,5-dimethyl aniline with palladium was also studied by transmission electron microscopy (Mallick et al. 2005). As it turned out, the polymer was formed in nanofibers. During oxidative polymerization, palladium ions were reduced and formed palladium metal. The generated metal was uniformly dispersed between the polymer nanofibers as nanoparticles of 2 mm size. So, Mallick et al. (2005) achieved a polymer- metal intimate composite material. This work should be juxtaposed to an observation by Newman and Blanchard (2006) that reaction between 4-aminophenol and hydrogen tetrachloroaurate leads to polyaniline (bearing hydroxyl groups) and metallic gold as nanoparticles. Such metal nanoparticles can well be of importance in the field of sensors, catalysis, and electronics with improved performance. 

A variety of nanomaterials have been synthesized by many researchers using anodic aluminum oxide film as either a template or a host material e.g., magnetic recording media (13,14), optical devices (15-18), metal nanohole arrays (19), and nanotubes or nanofibers of polymer, metal and metal oxide (20-24). No one, however, had tried to use anodic aluminum oxide film to produce carbon nanotubes before Kyotani et al. (9,12), Parthasarathy et al. (10) and Che et al. (25) prepared carbon tubes by either the pyrolytic carbon deposition on the film or the carbonization of organic polymer in the pore of the film. The following section describes the details of the template method for carbon nanotube production. 

The 0-d nanoparticles can be nano-metal oxides (such as silica,1 titania,2 alumina3), nano-metal carbide,4 and polyhedral oligomeric silsesquioxanes (POSS),5 to name just a few the 1-d nanofibers can be carbon nanofiber,6 and carbon nanotubes (CNT),7 which could be single-wall CNTs (SWCNT) or multiwall CNTs (MWCNT) etc. the 2-d nano-layers include, but are not limited to, layered silicates,8 layered double hydroxides (LDH),9 layered zirconium phosphate,10 and layered titanates,11 etc. 3-d nano-networks are rarely used and thus examples are not provided here. 

Spiral shaped hollow nanofibers were formed from the reaction of p-aminophenyl-p-D-glucopyranoside and p-dodecanoylaminophenyl-p-o-glucopyranoside with excess tetraethoxysilane. The diameter distributions of these tubes ranged from 1 to 2 nm and from 3 to 7 nm. Metal oxide nanotubes derived from this process displayed excellent hydrogen adsorption and storage capacity for potential use in hydrogen-powered vehicles. 

The wide assortment of polymer systans (polypropylene, poly(methyl methacrylate) [PMMA], polyepoxide, polystyrol, PC, etc.) is used as a polymeric matrix for nanocomposites production (Ray and Okamoto 2003). The most well-known fillers of polymeric matrix are nanoparticles (silica, metal, and other organic and inorganic particles), layered materials (graphite, layered aluminosilicates, and other layered minerals), and fibrous materials (nanofibers and nanotubes) (Thostenson et al. 2005). Nanocomposite polymer materials containing metal or metal oxide particles attract growing interest due to their specific combination of physical and electric properties (Rozenberg and Tenne 2008, Zezin et al. 2010). Nanocomposites on the base of layered materials... 

The dimensions of the added nanoelements also contribute to the characteristic properties of PNCs. Thus, when the dimensions of the particles approach the fundamental length scale of a physical property, they exhibit unique mechanical, optical and electrical properties, not observed for the macroscopic counterpart. Bulk materials comprising dispersions of these nanoelements thus display properties related to solid-state physics of the nanoscale. A list of potential nanoparticulate components includes metal, layered graphite, layered chalcogenides, metal oxide, nitride, carbide, carbon nanotubes and nanofibers. The performance of PNCs thus depends on three major attributes nanoscopically confined matrix polymer, nanosize inorganic constituents, and nanoscale arrangement of these constituents. The current research is focused on developing tools that would enable optimum combination of these unique characteristics for best performance of PNCs. 

The pol5mier nanocomposite field has been studied heavily in the past decade. However, polymier nanocomposite technology has been around for quite some time in the form of latex paints, carbon-black filled tires, and other pol5mier systems filled with nanoscale particles. However, the nanoscale interface nature of these materials was not truly understood and elucidated until recently [2 7]. Today, there are excellent works that cover the entire field of polymer nanocomposite research, including applications, with a wide range of nanofillers such as layered silicates (clays), carbon nanotubes/nanofibers, colloidal oxides, double-layered hydroxides, quantum dots, nanocrystalline metals, and so on. The majority of the research conducted to date has been with organically treated, layered silicates or organoclays. 

On the other hand, the oxidative coupling reaction of CH4 in the presence of Og, even when performed in membrane-type reactors, is mainly catalysed by metal oxide catalysts. Also oligomerisation, aromatisation and the partial oxidation to methanol or formaldehyde apply non-metallic heterogeneous catalysts (i.e. zeolites, supported metal oxides or heterogenized metalcarbon nanofibers or nanotubes from methane, these being catalysed by metal nanoparticles, but at the moment this is not considered as a Cl chemistry reaction. Again we direct the attention of the reader to some reviews on this type of process. ... 

In the phase separation approach, a polymer is solubilized and then undergoes the gelation process. Due to the physical incompatibility of the gel and the solvent, solvent is removed and the remaining structure, after freezing, is obtained in nanofibrilar form. Template synthesis implies the use of a template or mold to obtain a desired structure. Commonly metal oxide membranes with nanopores are used, where a polymer solution is forced to pass through to a nonsolvent bath, originating nanofibers, depending on the pores diameter. 

Drew, C., Liu, X., Ziegler, D., Wang, X., Bruno, F.F., Whitten, J., Samuelson, L.A. and Kumar, J. 2003. Metal oxide-coated polymer nanofibers. Nano Lett. 3 143-147. 

Polymeric electrospun fibers are known to enhance the structural performance of composite polymeric materials [4]. Nanofibers made of materials other than polymers, such as metal oxides, carbon, ceramics, as well as composite organic-inorganic systems, have also been obtained and can be used advantageously in the field of nanocomposites, thus widening the spectrum of application of electrospun materials. 

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