96 nanomaterials nanophase materials

Hydrothermal synthesis is a powerful method used for the fabrication of nanophase materials due to the relatively low temperature during synthesis, facile separation of nanopartides in the product, and ready availability of apparatus for such syntheses. Versatile physical and chemical properties of nanomaterials can be obtained with the use of this method that involves various techniques (e.g., control of reaction time, temperature and choice of oxidant and its concentration). Several extensive reviews are available that discuss the fundamental properties and applications of this method [2, 3]. These reviews cover the synthesis of nanomaterials with different pore textures, different types of composition [2, 4—6], and different dimensionalities in terms of morphology [6-8]. 

Nanophase materials are prepared by compacting the nanosized clusters generally under high vacuum. Synthesis of such nanomaterials has been reported in a few systems. The average grain sizes in these materials range from 5 to 25 nm. 

Nanophase materials generally have an excess heat capacity and entropy relative to the bulk. These can be obtained by conventional heat capacity measurements (adiabatic calorimetry, differential scanning calorimetry), although problems with the adsorbed water and other gases are more severe for nanomaterials than for bulk phases. Data at present are fragmentary and it is difficult to evaluate their accuracy. Dugdale et al. (1954) report on excess heat capacity for fine grained rutile. Victor (1962) report data for MgO and BeO, and Sorai et al. (1969) for Ni(OH)2 and Co(OH)2. 

Deanna L. Pickel joined the research staff at the Center for Nanophase Materials Science at Oak Ridge National Laboratory in July 2007. Her research interests are in the precise synthesis and characterization of well-defined materials, both in functionality and in architecture, to better understand the relationship between molecular structure and self-assembly at the nanoscale. In particular, she is interested in the use of MALDI-TOF MS to better understand the mechanism of various polymerization and functionalization chemistries. Deanna received her BS in chemistry and BA in mathematics in 1999 from Saint Mary s College in Notre Dame, IN, and PhD in 2003 from the University of Akron in polymer science under professor Roderic Quirk. Her doctoral research focused on the anionic synthesis and characterization of end functional polymers. She then joined Eastman Chemical Company in Kingsport, TN, where she worked on various process improvement projects and was a project leader for work on the weatherability of copolyesters. She moved to the Center for Nanophase Materials Science in July 2007, where she is a member of the Maaomolecular Nanomaterials Group. She is the recipient of the 2002 Eastman Chemical Company Fellowship, as well as a finalist in the 2002 Id Student Award in Applied Polymer Science. 

Nanophase material Nanophase materials or nanomaterials are an emerging group of materials produced in building blocks so small as to be measured in nanos, or 10 units. They have superior physical or mechanical properties compared with their conventional or bulk counterparts. Nanomaterials are made by controlling the arrangements of matter on atomic or molecular scales so as to create materials... 

Peter T. Cummings is the John R. Hall Professor of Chemical Engineering at Vanderbilt University. In addition, he is on the staff of the Chemical Sciences Division at Oak Ridge National Laboratory, where he also holds the position of director of the Nanomaterials Theory Institute of the Center for Nanophase Materials Science. He received his bachelor s degree in mathematics from the University of Newcastle (New South Wales, Australia) and his Ph.D. from the Univer-... 

The hydrogen storage capacities for disordered graphites, nanographites, and activated carbons are collected in Table 4.1. One can conclude that activated carbons are better storage materials than CNTs and most experimentally investigated carbon nanophases (like GNFs). Yet, if one applies a broader definition of nanomaterials, the activated carbon phases are, indeed, the disordered and nanostructured carbons. 

Metallic nanopartides were deposited on ceramic and polymeric partides using ultrasound radiation. A few papers report also on the deposition of nanomaterials produced sonochemically on flat surfaces. Our attention will be devoted to spheres. In a typical reaction, commerdally available spheres of ceramic materials or polymers were introduced into a sonication bath and sonicated with the precursor of the metallic nanopartides. In the first report Ramesh et al. [43] employed the Sto-ber method [44] for the preparation of 250 nm silica spheres. These spheres were introduced into a sonication bath containing a decalin solution of Ni(CO)4. The as-deposited amorphous clusters transform to polyciystalline, nanophasic, fee nickel on heating in an inert atmosphere of argon at a temperature of 400 °C. Nitrogen adsorption measurements showed that the amorphous nickel with a high surface area undergoes a loss in surface area on crystallization. 

The development of nanodevices and nanomaterials could open up novel applications in agriculture (Scrinis Lyons, 2007). Nanophasic and nanostructured materials are attracting... 

An innovative strategy to enhanee the mechanieal properties of biodegradable polymers is the ineorporation of nanomaterials as fillers within polymer matrices. With the appropriate modifications to facilitate dispersion into polymers and to enhance interactions with the snrronnding matrix, nanocomposites have demonstrated improved mechanical properties compared with unfilled polymers or polymers loaded with larger, micrometersized particles. A few studies have also shown enhanced cell function when bone cells are cultured on nanophase ceramic materials. 

Many isotropic nanomaterials consist of a concentrated set of isolated nanophases embedded in a homogeneous matrix, e.g., colloidal sols (solid nanoclusters embedded in a liquid matrix) and nanohybrid materials (solid inorganic clusters embedded in a solid polymeric matrix). Often, the set of clusters cannot be considered as dilute and uncorrelated, in the sense that the scattering intensity is not sinply given by I(q) = N- I q) (equation (8-14)) over the whole q range. The characteristics of the SAXS intensity produced by two types of systems conposed of spatially correlated nano-objects will be described (i) a homogeneous set of identical nanoclusters and (ii) a set of identical nanoclusters forming a two (or multiple) level structure. 

Figure 4.1 The biomimetic advantages of nanomaterials. (a) The nanostructuied hierarchical self-assembly of bone, (b) Nanophase titanium (top, atomic force microscopy image) and nanocrystalline HA/ helical rosette nanombe (HRN) hydrogel scaffold (bottom, scanning electron microscopy (SEM) image), (c) Schematic illustration of the mechanism by which nanomaterials may be superior to conventional materials for bone regeneration. The bioactive surfaces of nanomaterials mimic those of natural bones to promote greater amounts of protein adsorption and efficiently stimulate more new bone formation than conventional materials. Zhang, L., Webster, T.J., 2009. Nanotechnology and nanomaterials promises for improved tissue regeneration. Nano Today 4, 66-80.

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