Introduction
Carbon nanotubes are tube-shaped materials made of carbon, having a diameter measuring on the nanometer scale. Carbon nanotubes are members of the fullerene structural family. Their name is derived from their long, hollow structure with the walls formed by one-atom-thick sheets of carbon, called graphene. Carbon nanotubes have unusual properties because the bonding between the atoms is very strong and the tubes can have extreme aspect ratios. Nanotubes are categorized as single-walled nanotubes and multi-walled nanotubes (Fig 1).
Fig 1 Single-walled nanotube and multi-walled nanotube
Carbon nanotubes have extraordinary properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. In addition, owing to their extraordinary thermal conductivity, mechanical, and electrical properties, carbon nanotubes find applications as additives to various structural materials.
Applications
Pharmacy and Medicine: Carbon nanotubes have been successfully applied in pharmacy and medicine due to their high surface area that is capable of adsorbing or conjugating with a wide variety of therapeutic and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.). They have been first proven to be an excellent vehicle for drug delivery directly into cells without metabolism by the body.
Microelectronics: Nanotube-based transistors, have been made that operate at room temperature and that are capable of digital switching using a single electron. The use of carbon nanotubes transistor increases output current and compensates for defects and chirality differences, improving device uniformity and reproducibility.
Composite Materials: Carbon nanotubes powders mixed with polymers or precursor resins can increase their stiffness, strength, and toughness. Carbon nanotubes can also be deployed as additives in the organic precursors used to form carbon fibers.
Energy Storage: Carbon nanotubes' exciting electronic properties have shown promise in the field of batteries, where typically they are being experimented as a new electrode material, particularly the anode for lithium ion batteries. Carbon nanotubes can be bound to the charge plates of capacitors to dramatically increase the surface area and therefore energy density.
Other Applications: There are a variety range of applications of carbon nanotubes, such as solar collection, storage of liquid or gas, metal- free catalyst, nanoporous filters and coatings of all sorts.
