Link #41: Carbon Nanotubes Are the Strongest Materials Known to Man

Apr 6, 2015

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Link #41: Carbon Nanotubes Are the Strongest Materials Known to Man

Carbon_nanotube_armchair_povray — Carbon nanotube armchair povray. By Arnero PD image

For a long time, mankind believed that the strongest manmade substance in the world was steel, while the overall strongest substance in the world was diamond. However, all that has changed in the last couple of decades.

In 1991, scientists observed a substance which was dubbed carbon nanotubes. They soon discovered that the strength of carbon nanotubes far outstripped the strength of any other substance known to man.

What Are Carbon Nanotubes?

Eight_Allotropes_of_Carbon — Eight allotropes of carbon: a) diamond, b) graphite, c) lonsdaleite, d) C60 buckminsterfullerene, e) C540,Fullerite f) C70, g) amorphous carbon, and h) single-walled carbon nanotube. Created by Michael Ströck (mstroeck) GFDL

In simple terms, carbon nanotubes are formed when carbon molecules form specific types of structure that are extremely strong and resilient. These specific types of structures are often known as allotropes.

Different allotropes of carbon have been crucial to humanity at different stages of development. For instance, before carbon nanotubes were discovered, the strongest substance known to man was diamond. Diamond is also an allotrope of carbon.

Carbon nanotubes are formed when carbon molecules combine to form thin sheets called graphene. Sheets of graphene are then rolled to form cylindrical shapes which then become carbon nanotubes.

How Strong Are Carbon Nanotubes Really?

Chiraltube — A scanning tunneling microscopy image of single-walled carbon nanotube by Taner Yildirim (The National Institute of Standards and Technology – NIST).

Carbon nanotubes are not only the strongest substance known to man but also the stiffest. Carbon nanotubes’ strength is about 63 gigapascals. This means that a cable only as thick as 1 square millimetre of carbon nanotubes can withstand more than 6,400 kg of weight.

To put this into perspective even more and provide the right context, consider the fact that the specific strength (measurement that takes density into account) of carbon nanotubes (48,000 kN•m/kg) is 300 times higher than that of high carbon steel (154 kN•m/kg).

Carbon Nanotubes Are Very Versatile

It’s not only strength that carbon nanotubes are known for. They are also extremely versatile because they boast of various other qualities. Carbon nanotubes conduct heat wonderfully. They are also considered to be medium level semiconductors, which is rare for substances of their strength.

Why is this important? This is important because it increases the potential applications that carbon nanotubes can be used for. Even now, they are being mixed with a number of substances to improve their qualities and make them better for the intended use.

For example, their low density and good thermal and electrical qualities make them very useful when it comes to electronics. When their application is perfected, they have the capability of supporting the ever shrinking nature of electronic devices.

Carbon Nanotubes Can Make the Space Elevator a Reality

Artist concept: Space Elevator. Image by NASA

People who work with carbon nanotubes are extremely optimistic that their applications will grow as technology for manipulating them is discovered. One of the potential applications of carbon nanotubes is in building the space elevator.

A space elevator will connect the earth’s surface with a station in space. It will be useful for transporting objects from the surface to orbit around earth. The most modern designs of the space elevator depend on a rope like structure (tether) between space and the earth.

Experts now have plans to use carbon nanotubes for creating this tether. Mankind, as of now, doesn’t have the technology to make the tether, but if it can use carbon nanotubes to do so then the other elements of the space elevator will fall into place.