WRITTEN BY CONNOR WHITE
In 1991, a scientist named Sumio Iijima developed a material that consists of a single layer tube of carbon atoms bonded together. These tubes are called carbon nanotubes, or CNTs, and are a particularly useful part of nano technology. But how exactly are they made? What do we use them for now and what can we use them for going forward?
Carbon Nanotubes and How To Make Them
Carbon nanotubes are made from carbon atoms bonding together to form a hollow cylindrical tube. Thanks to their unique structure, carbon nanotubes can be 100 times stronger than steel. The tubes can also be layered with other nanotubes to create a stronger material. The word nano, in this case, can be misleading because these tubes can reach several millimeters, or even centimeters, in size. The longest carbon nanotube ever created reached 550 millimeters! There are a multitude of chemical and physical properties of carbon nanotubes that allow them to be especially useful. The tensile strength of carbon nanotubes is higher than that of steel and they can stretch up to 18% of their standard length. Carbon nanotubes are also very electrically and thermally conductive. The nanotubes are biocompatible as well. This means that they are non-toxic and non-reactive to biotic matter. These properties open many doors to the future of technology. A single layer of carbon nanotubes is called graphene, and it is one of the strongest materials known to humans. The carbon creates a honeycomb pattern when it bonds to other carbons and this gives the lightweight and conductive properties of the nanotubes (Figure 1).
Carbon nanotubes can be made in several ways: Arc discharge, laser ablation of graphite, and chemical vapor deposition. The first two of these methods contain the combustion of graphite using lasers or electricity. The carbon nanotubes are then formed and found in the gasses of the reaction. The final process of chemical vapor deposition (CVD), produces the best result of CNT. The CVD process can create the longest carbon nanotubes by filling a vacuum chamber with a gas containing carbon, such as methane, and using a liquid-metal catalyst, such as iron. When heating the chamber to temperatures approaching 750 degrees Celsius, the bond between the carbon and hydrogen gas breaks and sends the carbon into the liquid-metal catalyst. The hydrogen atoms are expelled from the reaction to prevent an explosion. Next, the metal-carbon solution becomes overwhelmed with carbon and begins to form outwardly. This reaction creates the single walled carbon nanotubes (Figure 2).
Carbon Nanotubes’ Current Usages
The production of carbon nanotubes is not cost effective, so they are not widely used. However, there are extremely interesting projects using the properties of the nanotubes. A company called DryWired has designed body armor made from a carbon nanotube fiber material that has a much higher resistance to bullets and knives. The nanotubes allow the armor to be stronger and tolerate force better than any other armor material. These revolutionary designs could save countless soldiers and keep countries safe.
Another field using carbon nanotubes is Biotechnology. As nanotubes have carbon bonded with three other carbon atoms, there is a left-over valence electron. This makes them great semiconductors and they can be used to create nanowires for biomedical or quantum engineering. Elon Musk’s NeuraLink has been researching smaller, more durable wires. Carbon nanotubes are a suitable candidate for this project and other projects with similar requirements, making a more efficient world.
Are Carbon Nanotubes Important for the Future of Technology?
There are countless ways that carbon nanotubes can improve and advance technology. Because of the lightweight and strong attributes of nanotubes, they could be used to improve pre existing technology by building more efficient automobiles, or even space shuttles. There is also an idea of lining airplanes with a carbon nanotube mesh, to remain safe from lightning strikes.
CNTs are biocompatible, so they are safe for any biomedical project. One of the more useful ideas would be exchanging power cables for carbon nanotube cables. Aluminum is used because it is cheap and light. However, it is a poor conductor and in turn loses quite a bit of energy. Carbon nanotube cables can conduct electricity much more efficiently and require less support.
Carbon nanotubes could change the world and improve almost anything–they are just waiting to be used properly. These structures could solve problems we do not even have yet! The possibilities for CNTs are endless. The world will see them used much more frequently in the coming years.