What is a carbon nanotube?

Well, discovered in 1991, a carbon nanotube (CNT) is a nanoparticle that's composed of carbon atoms arranged and linked to each other in a hexagonal shape. Every carbon atom in its structure is covalently bonded to three more carbon atoms, giving it its unique shape.

Carbon nanotube used for :

Now that we've answered 'what is a carbon nanotube?' let's learn about its different usages.

  • Carbon nanotube is 100 times stronger compared to steel, but is only 1/6th the weight of the latter. Hence, it finds easy usage in strengthening of almost any material.

  • What's also great about it is that it has several fascinating mechanical, electronic and magnetic properties that find application in fields like optics, electronics, nanotechnology and other related fields of materials science and technology.

  • Particularly speaking, its extraordinary thermal conductivity, apart from the electrical and mechanical properties makes carbon nanotube an excellent additive for many structural materials.

  • You'll find it included in tiny quantities in car parts, Damascus steel, golf clubs and baseball bats, all made primarily from carbon fiber.

  • It is also actively added to the polymers for enhancing or controlling their conductivity, and to the antistatic packaging.

Structural qualities of carbon nanotube

Carbon nanotube has a tube like shape and its diameter can be measured in nanometers. 1 nm is 10,000 times smaller compared to a human hair and is 1 billionth of a meter. What makes it unique is the strong bonding that exists between its atoms, allowing it to have extreme aspect ratios.

To put things into perspective, a carbon nanotube may have thinness equivalent to only a few nanometers, and yet have a length as high as several hundred microns. So, if human hair had the same kind of aspect ratio, one could witness a single strand being more than 40 meters long! That's remarkable to say the least!

The structures of carbon nanotubes may vary in terms of number of layers, thickness and length. Their characteristics may differ based on the manner in which the graphene sheet has been rolled up for giving it a tube like form, enabling it to function as a semiconductor or a metal. If looked at closely, the graphite layer constituting the carbon nanotube appears like a rolled-up chicken wire having an unbroken and continuous hexagonal mesh, with carbon molecules placed at the apex of every hexagon.

Types of carbon nanotubes

The answer to the question 'what is a carbon nanotube?' would be incomplete if we don't delve into different types of carbon nanotubes.

Carbon nanotubes can be of many different types, but are mainly categorized into MWNTs (multi walled nanotubes) or SWNTs (single walled nanotubes).

MWNTs - These are a collection of various nested tubes having continuously increasing diameters. These carbon nanotubes may either simply have just one inner and one outer tube (referred to as double-walled nanotubes), to anywhere around 100 tube walls, or more. All these tubes maintain their distance from their neighboring tubes through interatomic forces.

SWNTs - As evident from its name, a single walled carbon nanotube has just one wall. So, you may even liken it to a very fine straw that has just one wall or layer.

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