Carbon nanotubes (CNTs) are cylindrical molecules that consist of rolled-up sheets of single-layer carbon atoms (graphene). They can be single-walled (SWCNT) with a diameter of less than 1 nanometer (nm) or multi-walled (MWCNT), consisting of several concentrically interlinked nanotubes, with diameters reaching more than 100 nm. Their length can reach several micrometers or even millimeters.
CNTs are chemically bonded with sp2 bonds, an extremely strong form of molecular interaction. This feature combined with carbon nanotubes’ natural inclination to rope together via van der Waals forces, provides the opportunity to develop ultra-high-strength, low-weight materials that possess highly conductive electrical and thermal properties.
CNTs also have unique thermal and mechanical properties that make them intriguing for the development of new materials:
- their thermal conductivity is better than that of the diamond.
- they are very light-weight – their density is one-sixth of that of steel
- just like graphite, they are highly chemically stable and resist virtually any chemical impact unless
- they are simultaneously exposed to high temperatures and oxygen.
- their hollow interior can be filled with various nanomaterials, separating and shielding them from the surrounding environment – a property that is extremely useful for nanomedicine applications like drug delivery.
- CNTs find an incredible range of applications in electronics, materials science, energy management, chemical processing, and many other fields.
- CNTs have a very high surface area and very low electrical resistance which makes them attractive for energy storage applications.
- Carbon nanotubes can perform as a catalyst in a fuel cell, avoiding the use of expensive platinum on which most catalysts are based.
- Carbon nanotubes are being developed to clean up oil spills. Researchers have found that adding boron atoms during the growth of carbon nanotubes causes the nanotubes to grow into a sponge-like material that can absorb many times its weight in oil.
