What are Carbon Nanotubes? Uses, Properties and Structure

Carbon nanotubes (CNTs), also known as buckytubes, are an allotrope of carbon characterized by their hollow cylindrical structure, with walls that are only one atom thick. The carbon atoms are arranged in a hexagonal lattice, similar to graphene, and the tubes typically have a diameter of 1-3 nanometers.

CNTs have been deemed a wonder material due to their remarkable and highly unique physical and chemical properties. They have received much attention over the past decade as a promising material, particularly in the trending field of nanotechnology.

CNTs are super strong and yet highly versatile. Known for their outstanding optical, electrical, and mechanical properties, CNTs exhibit high flexibility, stability, and conductivity. They have applications across a broad range of fields including materials science, engineering, medicine, agriculture, and plant biotechnology.

The unique tube structure of CNTs shown in the video provides high strength as well as flexibility, whilst maintaining the high aspect ratio and surface area associated with graphene-based materials.

Carbon Nanotubes Structure

Carbon nanotubes (CNTs) are carbon-based nanomaterials with a tubular structure composed of rolled up graphene sheets. These tubes can consist of single or multiple graphene layers. CNTs share the same π-bond character as graphene, allowing electrons to be delocalized throughout the structure.

Carbon nanotubes are normally classified based on their wall structure as follows:

Multi-Walled Carbon Nanotubes (MWCNT)

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Single-Walled Carbon Nanotubes (SWCNT)

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Double-Walled Carbon Nanotubes (DWCNT)

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Graphene Carbon Nanotubes Composite

From $286

OH Functionalized Double-Walled Carbon Nanotubes

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The number of carbon nanotube layers dictates their name as well as their properties. CNTs come in different lengths (usually on the micron scale) as well as internal and external diameters (on the nano scale).

Carbon Nanotubes Properties

Carbon nanotubes are renowned for their excellent optical, electrical, and mechanical properties. Due to their nanoscale hexagonal lattice structure they demonstrate:

• High electrical conductivity: Electrons can pass through the structure with relative ease as electrons are delocalized.
• High stability: CNTs are both thermally and mechanically stable. They are resistant to large changes in temperature as well as external pressures.
• Low density: CNTs are light weight so only a small mass is required for a given application.
• Large specific surface areas: Enhancing their potential absorbency for substances like lead, heavy metal ions, dyes, and many other compounds.

Carbon Nanotubes Uses and Applications

Nowadays carbon nanotubes are in high demand and are utilized across a diverse range of applications. Research into CNTs is a highly interdisciplinary effort involving diverse fields such as physics, chemistry, biology, medicine, materials science, and engineering. CNTs can be used in:

• Automotive parts
• Electronics: circuitry, batteries, supercapacitors
• Photovoltaic technology - including solar panels, LEDs, sensors, transistors, field emitting devices, fuel cells, actuators (devices that power physical movement)
• Absorbents
• Catalysts
• Biomedicine: drug delivery, biosensing, bioimaging, nanorobotics, gene therapy and tissue regeneration
• Agriculture: bioremediation, water purification

Carbon nanotubes can be added to a material or substance (nanocomposite) to enhance strength. This is useful, for example, in the manufacture of sportswear, or materials used in the deflection of projectiles including bullet-proof vests.

Carbon Nanotube Functionalization

The possibility of the surface modification of carbon nanotubes offers the potential to enhance certain characteristics. By adding functionality like carboxylic acid and hydroxy groups the solubility of CNTs can be tuned. CNTs are chemically stable and highly resistant to acid and alkaline conditions, thus reducing the risk of corrosion. When taken together, all of these amazing and relatively rare properties mean CNTs have attracted a lot of attention. CNTs are the most widely utilized nanomaterial - other examples being nanodiamonds, fullerenes (hollow carbon molecules) and graphene.

History of Carbon Nanotubes

CNTs were a much anticipated “material of dreams” just half a century ago (Endo et al. 2006). They were first synthesised by Endo in 1976. Then in 1991, Iijima reported the preparation of carbon structures consisting of needle-like tubes, in the prestigious journal “Nature”. Electron microscopical analysis gave a detailed picture of their molecular structure, revealing coaxial (where several 3D linear or planar forms share a common axis) tubes of graphite sheets ranging from 2 to around 50 nm. The synthesis of these nanometre size tubes drew a great deal of interest amongst researchers, not least for their unlimited potential and prospects for engineering these microstructures on a much larger scale.

Multi-Walled Carbon Nanotubes (MWCNT)

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What are Multi-Walled Carbon Nanotubes?

Multi-walled carbon nanotubes (MWCNTs) consist of multiple carbon nanotubes nested within one another. The carbon nanotubes are just one atom thick and this gives MWCNTs unique electrical and mechanical properties.

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What are Single-Walled Carbon Nanotubes (SWCNT)?

Single-walled carbon nanotubes (SWCNTs) are sheets of graphene that have been rolled up to form a long hollow tube, with wall thickness of a single atom. Their one-dimensional structure gives them extraordinary mechanical, electrical and thermal properties.

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