Motivation and Background

Discovery of C60 in 1985 triggered a world-wide surge of research activities towards fullerenes and nanocarbons, which culminated into the 2001 Clinton Speech before the US Congress in which nanotechnology was declared as one of the major technological goals of the 21st century. The brave proposition reflect inevitable trend of chemistry and materials science to approach towards each other, hence may appear a very reasonable step in the historical evolution of technology. Traditionally, chemistry has been dealing with invisible molecules while materials science with visible particles, but now we are going to develop a technology on invisibly small materials.

The merge imposed considerable strain on the researchers of both sides. Chemists were perplexed at the insoluble, non-volatile, non-melting, and non-subliminal gigantic molecules having extremely large surfaces of the orders of a few hundred m2/g. It is painful for chemists to handle molecules that cannot be purified to 100% purity. Material scientists had to cope with particles, the size of which they have never handled before. It is clear that nanotechnology needs extensive supports from scientific research on the fundamental aspects of nanoparticles, which is the mission of our venture company.

Nanoscience should be best practiced in the course of developing appropriate type of nanoparticle capable of industrial applications. From the very beginning we chose to concentrate on nanocarbons, because of our long commitments in fullerenes since the discovery of C60. However, it soon became evident that typical fullerenes like C60 and carbon nanotubes are not necessarily the best targets of business, not only due to their peculiar sizes and shapes, but also because of the patent rights already secured by major enterprises. We had to retreat from the fullerene front for the time being. In reality, the business of these two highly esteemed fullerenic carbons is being much delayed, hence our choice was right.

Our own analysis revealed that commercialization of nanocarbons needs to fulfill four pre-requisites. In addition to the well-known, almost mandatory condition of low cost, biocompatibility is equally important. Two more conditions are the high crystalline order in the atomistic structure and the predictable existence of large market. The importance of crystalline order is best illustrated by carbon blacks or industrial soot, which possess an ideally low cost and structural uniformity, and have been used for more than a century on large scale but never grew out of the subsidiary status of an additive to rubbers, because of extremely low structural order. In contrast, both C60 and carbon nanotubes have remarkably high atomistic order in structure but, being so new in basic structure, it is difficult to find new markets.

We had an eye to the dispersed detonation nanodiamond as the ace among the known nanocarbons. The primary particles of this diamond have an average diameter of 4.50.5 nm, and will be called hereinafter as single-nano diamond (our own naming) or dispersed ultrananocrystalline diamond (DUNCD, according to the nomenclature of Dieter Gruen). DUNCD satisfies all the four requirements mentioned above:

(1)Production cost. DUNCD is isolated from soot produced by exploding a popular military explosive Composition B (TNT+RDX) in water or other inert media. Note that the expired military explosives have negative price.

(2)Biocompatibility. Careful studies on the cytotoxity confirmed total absence of toxity in DUNCD (see Publication Section for references).

(3)Ordered atomic structure. The primary particle of DUNCD is a single cubic diamond crystal containing about 5000 carbon atoms. With such a large number of constituent atoms, in contrast to diamondoids and adamantanoids, we can duly expect that DUNCD retains most of the properties known to bulk diamond (Table 1, link). Due to the closest packing, diamond has long been rated as the best general-purpose industrial material known on earth, especially excelling in hardness, Youngs modulus, transparency, chemical inertness, thermal conducticity and doping possibilities.

(4)Marketability. What is the reason for the artificial diamonds never having been used widely as a versatile industrial material? This question is especially pertinent to the HTHP microdiamonds which have appeared in the market half a century ago and its production technology has matured well. The answer is quite simple: diamond was too hard to manipulate, thus remained impossible to process or mould. As a consequence, this potentially useful material has so far been confined to only a relatively small market of polishing material.
Likewise, detonation nanodiamond was discovered 40 years ago and commercialized for 15 years but performed even worse than microdiamond; it never acquired a status of commodity. In this case, the product on market was actually tight agglutinates having 100-200 nm in diameter with its performance dominated by its amorphous inter-grain boundaries.
In contrast, the dispersed single-nano diamond particles retain most of the properties of bulk diamond, and still should be amenable to the known processing technology of nanoparticles. Individual primary particles are large enough to use as the particulate material as well. We duly expect that DUNCD will prove a highly versatile material for a variety of applications. So far the preliminary results of our own experiments attest these expectations.
It is our mission to develop fundamental knowledge and techniques of nanotechnology through the production, purification and application of dispersed primary crystallite particles of single-nano diamond.