Nanostructural material

Rittner M N and Abrham T 1998 Nanostructured materials an overview and commercial analysis COM 36... 

Siegel R W 1994 Nanostructured materials mind over matter Nanostruct. Mat. 4 121... 

The comparatively new field of nanostructured materials has its own journals (though the first one has now been merged with another, broader journal) and frequent conferences it is a good example of a parepisteme which appears to be successful. The best single source of information about the many aspects of the field is a substantial multiauthor book edited by Edelstein and Cammarata (1996). 

An excellent, accessible overview of what surface scientists do, the problems they address and how they link to technological needs is in a published lecture by a chemist, Somorjai (1998). He concisely sets out the function of numerous advanced instruments and techniques used by the surface scientist, all combined with UHV (LEED was merely the first), and exemplifies the kinds of physical chemical issues addressed - to pick just one example, the interactions of co-adsorbed species on a surface. He also introduces the concept of surface materials , ones in which the external or internal surfaces are the key to function. In this sense, a surface material is rather like a nanostructured material in the one case the material consists predominantly of surfaces, in the other case, of interfaces. 

Gleiter, H. (2000) Nanostructured materials basic concepts and microstructure, Acta Mater. 48, 1. 

Hollow carbon nanotubes (CNTs) can be used to generate nearly onedimensional nanostrutures by filling the inner cavity with selected materials. Capillarity forces can be used to introduce liquids into the nanometric systems. Here, we describe experimental studies of capillarity filling in CNTs using metal salts and oxides. The filling process involves, first a CNT-opening steps by oxidation secondly the tubes are immersed into different molten substance. The capillarity-introduced materials are subsequently transformed into metals or oxides by a thermal treatment. In particular, we have observed a size dependence of capillarity forces in CNTs. The described experiments show the present capacities and potentialities of filled CNTs for fabrication of novel nanostructured materials. 

How can such problems be counterbalanced Since a large capacitance of a semiconductor/electrolyte junction will not negatively affect the PMC transient measurement, a large area electrode (nanostructured materials) should be selected to decrease the effective excess charge carrier concentration (excess carriers per surface area) in the interface. PMC transient measurements have been performed at a sensitized nanostructured Ti02 liquidjunction solar cell.40 With a 10-ns laser pulse excitation, only the slow decay processes can be studied. The very fast rise time cannot be resolved, but this should be the aim of picosecond studies. Such experiments are being prepared in our laboratory, but using nanostructured... 

Nano-composites (NCs) are materials that comprise a dispersion of particles of at least one of their dimentions is 100 nm or less in a matrix. The matrix may be single or multicomponent. It may include additional materials that add other functionalities to the system such as reinforcement, conductivity and toughness (Alexandre and Dubois, 2000). Depending on the matrix, NCs may be metallic (MNC), ceramic (CNC) or polymeric (PNC) materials. Since many important chemical and physical interactions are governed by surface properties, a nanostructured material could have substantially different properties from large dimensional material of the same composition (Hussain et ah, 2007). 

Application of the above techniques has enabled the synthesis of a range of nanostructured materials with tunable composition, physical properties, and... 

The introduction of new synthetic techniques has led to the discoveries of many new electronic materials with improved properties [20-22]. However, similar progress has not been forthcoming in the area of heterogeneous catalysis, despite the accumulation of considerable information regarding structure-reactivity correlations for such catalysts [14-19]. The synthetic challenge in this area stems from the complex and metastable nature of the most desirable catalytic structures. Thus, in order to minimize phase separation and destruction of the most efficient catalytic centers, low-temperature methods and complicated synthetic procedures are often required [1-4]. Similar challenges are faced in many other aspects of materials research and, in general, more practical synthetic methods are required to achieve controlled, facile assembly of complex nanostructured materials [5-11]. 

As has been shown above, oscillatory electrodeposition is interesting from the point of view of the production of micro- and nanostructured materials. However, in situ observation of the dynamic change of the deposits had been limited to the micrometer scale by use of an optical microscope. Inspections on the nanometer scale were achieved only by ex situ experiments. Thus, information vdth regard to dynamic nanostructural changes of deposits in the course of the oscillatory growth was insufHcient, although it is very important to understand how the macroscopic ordered structures are formed with their molecular- or nano-components in a self-organized manner. 

H. Bdnnemann, W. Brijoux, in W. Moser (ed.) Advanced Catalysts and Nanostructured Materials, Chapter 7, Academic Press, San Diego, CA, 1996, 165. 

N. Toshima, in N. Ueyama, A. Harada (eds.), Macromo-lecular Nanostructured Materials, Springer and Kodansha Scientific Ltd., Tokyo, 2004. 

When any materials interact with their environment through solid/gas, solid/liquid, and solid/solid interfaces, the nanometer scale surface created can easily be modified to perform certain functions. The modifications are usually only effective in the few nanometer deep surface layers. This chapter highlights the development of new model nanostructured materials with functionalized interfaces to... 

F. Gonella, P. Mazzoldi, Metal nanocluster composite glasses, in H. S. Nalwa (ed.) Handbook of Nanostructured Materials and Nanotechnology, Vol. 4, Academic Press, San Diego, 2000, 82. 

Mossbauer spectroscopy has been extensively used for studies of nanostructured materials and several reviews on magnetic nanoparticles have been published, see e.g. [6-8, 46 8]. The magnetic properties of nanoparticles may differ from those of bulk materials for several reasons. The most dramatic effect of a small particle size is that the magnetization direction is not stable at finite temperatures, but fluctuates. 

This series will cover the wide ranging areas of Nanoscience and Nanotechnology. In particular, the series will provide a comprehensive source of information on research associated with nanostructured materials and miniaturised lab on a chip technologies. 

J. R. Groza 2002, in Nanostructured Materials - Processing, Properties and Potential Applications, ed. C. C. Koch, William Andrew Publishing, New York, chap. 4. 

Nanostructured materials are nothing new. Chrysotile fibers are an example (Fig. 16.22), as are bones, teeth and shells. The latter are composite materials made up of proteins and embedded hard, nanocrystalline, inorganic substances like apatite. Just as with the imitated artificial composite materials, the mechanical strength is accomplished by the combination of the components. 

Aside from the methods for the production of carbon nanotubes mentioned on page 115, a number of methods to make nanostructured materials have been developed. In the following we mention a selection. 

Nanostructured materials have found several applications, and more are to be expected, for example ... 

Stang, P. J. Olenyuk, B. Transition-metal-mediated self assembly of discrete manoscopic species with well-defined structures and shapes. In Handbook of Nanostructured Materials and Nanotechnology, Nalwa, H. S.. Ed. Academic Press San Deigo, 2000, Vol. 5, 167-224. 

Tacaman, M. J., L. Rendon, J. Arenas, and M. C. Serra Puche (1996), Maya-Blue An ancient nanostructured material, Science 273, 223-225. 

---