The discovery of fullerenes (new allotrope form of the element Carbon, organized in a football like structure) in 1985 was the start for new developments in different fields beyond material science and technology which will also influence our daily live. A few years later, the elongated form of fullerenes, the carbon nanotubes (CNTs), were described. Today, three allotrope forms of carbon were known: graphite, diamond and fullerenes.
The carbon atoms in the nanotubes are hexagonal organized. The tubes consists of a single layer of graphene which is seamless enrolled to a tubular form of a few nanometers in diameter and may have several millimeters in length.
The carbon nanotubes were mainly distinguished in two classes: single-walled carbon nanotubes (SWCNT) with one layer and multi-walled carbon nanotubes (MWCNT) with several layers of graphene. Because of their geometry and hydrophobic surface, carbon nanotubes have a tendency to form agglomerates (Van-der-Waals-forces).
Carbon nanotubes have remarkable properties: e.g. the strength of the tubes is determined to 63 GPa which is 50 times higher than steel. Dependent on the chirality the electrical properties of the tubes may be conductive or semi-conducting which make them interesting e.g. for the transistor technology. The desired properties of the tubes are achieved already during the synthesis.
Because of their extraordinary properties carbon nanotubes are and will be used in a variety of applications such as transistors, storage, composites or metrology.