Nanotube
A nanotube (English nanotube ) is an elongated hollow body with a diameter of less than 100 nanometers. Particularly important and well -studied carbon nanotubes ( CNTs for short ), there are also nanotubes of boron nitride, titanium dioxide, sulfides ( molybdenum and tungsten, copper (II ) sulphide ) and halides ( nickel chloride, cadmium chloride, cadmium iodide ).
The production and potential use of nanotubes is studied intensively in the context of nanotechnology: In 2002, about 3,000 scientific publications on nanotubes have been published.
Properties
Of all the materials mentioned in the introduction has long been known that they can form analogous to carbon in the form of graphite, layer structures. Even plastic can produce nanotubes.
Typically, the diameter of a nanotube is only a few nanometers; the inner tubes in multi-walled nanotubes can be up to 0.3 nanometers thick. Thus, they are some 1/10.000 as thin as a human hair. In carbon nanotubes lengths of 20 centimeters have been achieved. However, typical lengths of several microns.
Nanotubes can be single- or multi-walled and the wall can form both a closed ring and a spiral structure. The ends of the tubes may be closed or open, and the interior can be empty or filled. Carbon nanotubes, for example, could, at least partly, be filled already with liquid lead. Depending on production conditions arise even whole bundles or strands of nanotubes.
Applications
Scientists think about a space elevator, which is connected by nano- ropes with the earth's surface. On such a rope a space elevator could carry, such as satellite into space or space stations provide cost-effective.
In May 2013, Bayer announced that Bayer MaterialScience sets the commercialization of carbon nanotubes. The work around CNTs should " be completed " for the know -how a buyer being sought. The possible application areas are "very fragmented", an extensive commercialization is not yet in sight.
Criticism
Critics point out that the risks of nanotechnology have so far been insufficiently explored. There are indications that certain nanotubes, similar to asbestos fibers, can favor the development of cancer.