Revised structure of the primary particle of single-nano detonation diamond (SNBD) are constructed by merging our own experimental observations with the results from self-consistent charges density functional tight binding (SCC-DFTB) calculations by Barnard. Internal geometrical structure is characterized by triply-decked core-shell structure with graphene layers on the surface, electronic structure by strong electrostatic potential fields of both signs over the facets, and surface structure by intermixed graphene/diamond patches. Surprisingly high stability of colloidal solution of SNBD is interpreted in terms of strong hydration over the charged facets. Rapid aggregation of primary particles by the changes in pH and the addition of electrolytes are mentioned by invoking ligand exchange reactions that take place on the charged facets involving hydrated water molecules and protons or metallic ions. In this way a considerably improved picture on the characteristic behaviors of this novel nanocarbon emerged. The most remarkable feature of SNBD is that diamond polarizes in nano.
We have developed low temperature and large area nanocrystalline-diamond growth methods using microwave plasma-assisted chemical vapor deposition sustained by surface waves. Highly transparent and smooth nanocrystalline-diamond films were successfully grown on borosilicate glass, aluminum and other substrate materials by this method. Properties of our films were examined by using UV-excited Raman spectroscopy, X-ray diffraction, atomic force microscopy, and other techniques. Possible applications of our nanocrystalline-diamond films are discussed.
Since nanodiamonds (NDs) exhibit low or no toxicity, NDs have attracted growing interest as promising materials for biomedical applications. Herein are reported size separation of ND particles by use of ultracentrifugation and synthesis of fluorescent ND through the surface chemical modifications. The convenient size separation method by use of ultracentrifugation gave desired sizes of NDs ranging from 4 to 25 nm in medium diameters by controlling the duration and acceleration of the centrifugation. The ND size is important for passive targeting such as EPR effect in their applications for DDS and tumor imaging. Surface chemical modification is also vital for adding requisite functions to NDs such as dispersibility and visibility. Step-wise transformations on ND surface were performed, providing fluorescent ND. The ND powder with 30 nm medium diameter was hydrogenated, followed by functionalization with aminoalkyl group via radical reaction. Fluorescent tag was immobilized onto the ND surface through amide linkage, which was confirmed by fluorescent image of the ND.
New composite materials were fabricated by the incorporation of nanodiamond into plated films. The nanodiamond content in the films was found to saturateat around 2% as the concentration in the bath was increased. It was found that a strong interaction must be induced between the nanodiamond and the deposition frontier in order to incorporate larger concentrations into the films. A content of 5.6% was achieved by the addition of surfactants and brighteners to the baths. Refinement of the nanodiamond by boiling sulfuric acid with nitrate ions was found to be necessary to achieve good reproducibility. The films with 5.6% nanodiamond content were also produced using iodide ions for the refined nanodiamond. In addition, a Ni-P-nanodiamond composite film with a 14% nanodiamond content was successfully fabricated from a bath that contained only citrate as a complexing agent. Finally, the co-deposition mechanism of nanodiamond in plated films was identified. A very low friction coefficient of 0.03-0.04 was achieved for Ni-W-P-nanodiamond plated films.
The structural characteristics of the ultra-dispersed diamonds are the size of 10 nm grain, diamond core, interlayer of non-diamond carbon, and outermost layer of surface groups. By making the best use of forementioned characteristics, the applications in the market are for super precise polishing, lubricant, composite electrolytic coatings, deodorization and antimicrobial use. Due to their uniqueness, it is highly expected that the expansion of their application into the field of flat panel display, car electronics, and biotechnology will happen with efforts at improvement in the grain diameter control, purity control, the surface modification control and the lattice defect control technology.
Method of mapping an inelastic electron tunneling signal observed by scanning tunneling microscope (STM) with feedback active is presented, where the influence of the modulation voltage to the z-piezo of STM is minimized. With this method, identification of hexanethiol molecules embedded into the matrix of its isotope is demonstrated.