iii. Carbon Nanotubes (CNT) – Definition, Types & Properties

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iii. Carbon Nanotubes (CNT) – Definition, Types & Properties

About	Type of One-dimensional Nanomaterial. Carbon is very abundant in nature. They exist in different forms from the rice you eat to the petrol burn to the diamond you wish to wear. Petrol, rice, diamond all appear different though they are made of same thing (at least in part). How is it possible? It’s all about how the atoms arrange that decides the formation of different substance you see. If you take carbon and heat it up to very high temperatures the carbon atoms arrange themselves like clusters each made of 60 carbon atoms. (they become stable by arranging themselves) If you make a cluster using 60 carbon atoms arranging them in the shapes of pentagon and hexagon you make a football like structure called fullerene or spherical buckyballs. (named after a scientist) Before this only forms of carbon know were graphite and diamond. These cage-like balls withstand high temperature and pressure. (you heat it more nothing happens) Now imagine stretching this buckyball/football into a sheet and rolling the sheet and cap it at both ends. This is carbon nanotube. If you have one layered tube it is called single-walled, 2 layers it is called double-walled CNTs, many more layers you call it multi-walled.
Properties of Carbon Nanotubes	High strength with low-weight: Single-walled CNTs are 100 times stronger and 1/6th its weight. Thus, can be used to make light-but-strong materials. Hollow, tubular structure make it ideal as storage box. Gas, lithium, even drugs may be stored. (drug delivery) Very good conductors of heat and electricity. Can exist as both as semi-conductors and metals. In addition, we can manipulate CNTs to change from being a semiconductor to a metal and vice versa. Large length-to-width ratio Self-assembling properties: scientists have harness the ability of self-assembly of bio molecules for various applications. CNTs are attached to DNA and proteins to make novel materials that have unique properties. CNTs are mixed with other materials to make composites like conductive plastics or steel-like plastics. CNTs can be used to store hydrogen. About 2/3rd of CNTs are semiconducting and 1/3rd metallic. Separation is a problem hindering mass production CNTs are insoluble in water. This can be solved by attaching it with organic matter like starch.
Plant-Based CNT	Conventionally we use petro-hydrocarbons such as methane and benzene thereby impacting its carbon footprint. CNTs can be made using camphor, a green plant product, turpentine, oil from linseed, mustard and cotton seed.