Nanotechnology is one of the key technologies of the 21st century. The prefix "nano" comes from the Greek word "nanos"’ meaning dwarf. Nanotechnology deals with a scale that is over 10,000 times smaller than a millimetre. It involves investigating, producing and applying structures that are smaller than 100 nanometres (nm).
A nanometre is to a metre as the diameter of a hazelnut is to the earth.
A nanometre is a billionth of a metre (= 0.000 000 001 m)
Nanotechnology develops the basis for increasingly smaller data memories with increasingly larger storage capacity, for highly efficient filters for sewage treatment, for photovoltaic windows, for materials which can be used to build ultra-light engines and body parts in the automobile industry or for artificial joints which are better tolerated by the human body due to organic nano-surfaces.
In the future, as nanoscale molecular self-assembly becomes a commercial reality, nanotech will move into conventional manufacturing. While nanotechnology offers opportunities for society, it also involves profound social and environmental risks, not only because it is an enabling technology to the biotech industry, but also because it involves atomic manipulation and will make possible the fusing of the biological world and the mechanical. There is a critical need to evaluate the social implications of all nanotechnologies; in the meantime, the Arry Group believes that a moratorium should be placed on research involving molecular self-assembly and self-replication. (Sources: Nanotruck and BMBF.)
Carbon nanotubes, long, thin cylinders of carbon, were discovered in 1991 by S. Iijima. These are large macromolecules that are unique for their size, shape, and remarkable physical properties. They can be thought of as a sheet of graphite (a hexagonal lattice of carbon) rolled into a cylinder. These intriguing structures have sparked much excitement in the recent years and a large amount of research has been dedicated to their understanding. Currently, the physical properties are still being discovered and disputed. What makes it so difficult is that nanotubes have a very broad range of electonic, thermal, and structural properties that change depending on the different kinds of nanotube (defined by its diameter, length, and chirality, or twist). To make things more interesting, besides having a single cylindrical wall (SWNTs), nanotubes can have multiple walls (MWNTs)--cylinders inside the other cylinders.
With graphene tubes parallel to the filament axis, nanotubes would inherit several important properties of ‘intra-plane’ graphite. This imparts a very unique combination of properties on this material, namely:
-- High aspect ratio structures with diameters in nanometers, lengths in microns
-- High mechanical strength (tensile strength 60GPa) and modulus (Young’s modulus 1TPa)
-- High electrical conductivity (10-6 ohm m typically), and for well crystallised nanotubes ballistic transport is observed
-- High thermal conductivity (1750-58 00 W/mK)
-- Being covalently bonded, as electrical conductors they do not suffer from electromigration or atomic diffusion and thus can carry high current densities (107 -109 A/cm2 )
-- Single wall nanotubes can be metallic or semi-conducting
-- Chemically inert, not attacked by strong acids or alkali
-- Collectively, nanotubes can exhibit extremely high surface area
The strength and flexibility of carbon nanotubes make them potentially useful in a wide variety of applications in nanotechnology, electronics, optics and other fields of materials science. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Inorganic nanotubes have also been synthesized.
Arry has done a lot of research and development work in the carbon nanotubes synthesis and application, and developed a scalable CVD method to produce high purity single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) with various diameters and narrow diameter distribution.
The technology for producing 5kg 20-40nmMWNTs per day was evaluated as an advanced technology in the world by CAS scientists.
We can produce 1.5kg SWCNTs per day and 10kg MWNTs with 8-15nm in diameter per day. The production facilities can be enlarged easily. And MWNTs with purity more than 98wt% max.