Diamond materials surface modification

In addition to C onions, C atoms condense into various kinds of chemically bonded forms, and they are known to have excellent physical properties depending on the bonding nature. This means that research and applications not only in the materials science but also in other scientific fields are expected. At JAERI, the optimum growth conditions have been successfully obtained for the preparation of high-quality Cgo, diamondlike carbon, and nanocrystalline diamond by means of ion-beam-assisted deposition [80-82]. The susceptibility of Ni/Cgo thin films to thermal treatment, the formation of nanocrystalline diamond and nanotubes due to codeposition of Co and Ceo, and the surface modification of glassy... 

For many years the studies of surface modifications of synthetic diamond nanopowders have been conducted at the Institute for Superhard Materials. Our findings show that highly dispersed modified diamond powders hold a considerable promise in applications as adsorbents and catalysts of the oxidation and electrochemical catalysis [1-4], This promise is based on the following special features of the material ... 

The development of diamond catalysts involved special two-stage treatment of the diamond nanopowder surface, the so-called modifications. Figure 1 gives the schematic of the reception of electrode materials. As is seen from the schematic, the hydrogen electrode was make from special heat-treated treatment in the hydrogen environment [6]. 

A modification of functional groups already attached to the nanodiamond surface is of considerable interest for the development of new diamond materials for biomedical or mechanical applications. 

In the following chapters of this textbook, different aspects of electrochemical research on carbon materials will be discussed in detail, including carbon electrodes in different applications (fuel cells, molecular electronics, sensing, etc.) using various methods (surface modification, carbon paste, carbon fiber, etc.), and electrochemistry of different carbon materials (graphene, HOPG, carbon nanotube, diamond, etc.). 

Differences in the surface conductivity with surface termination of diamond can be applied to the nanolithographic modification of diamond surfaces by use of atomic force microscopy (AFM) techniques [50-52]. Modification can be carried out by applying an electrical bias to the sample surface via a conductive cantilever tip, e.g., Au coated Si (Fig. 8.8). Surface modification using such an AFM technique is relatively general, and has been achieved for semiconductor materials such as Si [53], GaAs [54] and metals such as Ti [55]. Recently, Tachiki et al. and Kondo et al. have applied this technique to single-crystal homoepitaxial diamond thin films, undoped and boron-doped, respectively. In this section, we discuss the properties of diamond surfaces modified via AFM techniques and possible applications. 

Thus, inter-atomic distances and the atomic state in Tetracarbon are fundamentally different from all the known forms of carbon. The differences between clear and hard diamond on the one hand, and soft and black graphite on the other hand, illustrate the differences among Tetracarbon and other forms of carbon. The distance between the neighboring sp -carbon atoms within the Tetracarbon chain is about 1.3 A, whereas the distance between the carbon chains is 4.80-5.03 A. It is interesting to note that in some respects Tetracarbon is similar to tubulenes, as it can be considered as tubulene in the limit when the diameter of the tube approaches the diameter of carbon atom. Nevertheless, in Tetracarbon the hybridization state of carbon atoms changes from sp to sp. It is basically a new purely one-dimensional sp -carbon modification with one-dimensional electron band structure, whereas tubulene is a quasi-one-dimensional material in which the number of one-dimensional electron bands increases with increasing tubulene diameter. Tetracarbon and tubulene are also similar in that the carbon chains in Tetracarbon are oriented normally to the surface of the film, similar to the orientation in tubulene. 

It is commonly recognized that a comprehensive understanding of the properties of a new material is an essential prerequisite to finding its new applications. In this respect, the study of ultrafine diamond is incomplete and its properties remain to be fully elucidated. For example, the nature of the surface functional groups and the method of their modification the nature of the agglomeration of ultrafine crystallites and effective methods of de-agglomeration to prepare mono-dispersed suspension the crystalline and surface structures of the nano-scaled diamond, etc., are appropriate subjects of research An efficient method for the determination of particle size distributions and structures of nano-sized particles in suspension is very important, and is worth developing in the near future. 

Chemical modification of diamond surfaces is a ripe area for research. Much can be learned about (1) how to control the electrode reaction kinetics and mechanisms at diamond through alterations of the surface chemistry and (2) using such modified surfaces as platforms for sensors and other devices based on the material. 

Antibacterial materials have been employed in numerous applications, ranging from biomedical products to packing materials to air-filter systems. The first approach has focused on reducing the capacity of bacteria to attach onto a surface. Some methods to achieve this adhesion resistance rely on the modification of substrates by poly(ethylene glycol) [OST 01] or the use of diamond-like carbon films [ZHA 07], Recently, superhydrophobic surfaces [PAR 05] created via a combination of chemical modifications, such as... 

Sensor surfaces can consist of most materials. Metals, oxide ceramics and carbon in its different modifications including diamond, silicates and organic... 

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