Carbon nanotubes are made of the thinnest element on earth: graphene. But while graphene itself lays flat, one atom in thickness, carbon nanotubes are, as you might expect, tubes. Their walls are made of graphene, but they behave a bit differently than flat graphene, and also are significantly different from graphene oxide (GO).
Interestingly, carbon nanotubes (CNT) were discovered and put into use before flat graphene was first synthesized. In fact, although graphene has only existed since 2004 (see our article on graphene), carbon nanotubes are as old as time itself. This is because carbon nanotubes are naturally occurring structures that have always been with us. Still, our awareness of CNT is relatively recent. Carbon nanotubes were first detected in bound bundles by chemist Sumio Iijima. That initial discovery took place in 1992. Two years later, Iijima would discover single-walled carbon nanotubes, consisting of lone, free-standing cylinders of rolled graphene. This ultimately led to the creation of artificial CNT for industry.
As one might expect, carbon nanotubes are sturdier than their “sister chemicals” graphene and graphene oxide. As such, they have many of their own unique uses. Of course, CNT, like all graphene-based chemicals, are highly conductive. So you’ll see some overlap in the ways that CNT, graphene, and graphene oxide are used.
Common Uses of CNT
- Water filtration: Carbon nanotubes, with their sturdy structure, are used as the framework for water filtration membranes. These membranes, with their fine, nano-scale mesh, are very effective at cleaning water and making it drinkable. This highlights an interesting difference between CNT, GO, and graphene. While GO and graphene are finer than CNT and thus capable of both desalination and water filtration, CNT’s formidable nano-structure may make it a more effective agent for water purification.
- Battery electrodes: Here is another instance where CNT arguably outshines graphene and GO. While graphene, GO and CNT are all highly conductive, CNT’s more complex structure makes for a larger, more interconnected surface area. This really boosts conductivity on battery terminals, especially larger ones.
- Strengthening materials: Carbon nanotubes have the tensile strength of graphene– the strongest known substance– and they wind graphene into a sturdy network of tubing. So needless to say, CNT can really enhance the structural integrity of many materials. CNT is infused into items as varied as sports equipment, body armor, motor vehicles and bicycle frames, boosting structural strength and improving shock absorption.
- Electronic ink: Electronic ink is used in displays such as touch screens, sensors, and other electronic devices that display and read information. Graphene itself is already well established as a conductive basis for electronic ink. But graphene carbon nanotubes are starting to emerge as an alternative ingredient. The disadvantage is that CNT is less granular and flexible. However, its interconnected framework also makes it a much more conductive electric ink agent. As CNT ink technologies improve, it’s certainly an option to consider.
- Semiconductors: This is another area where the networked, highly connected nature of the carbon atoms in CNT really comes in handy. Next generation computers are starting to utilize CNT for highly efficient semiconductors. CNT’s nano-sized conductive networks allow for much denser conductivity, enhancing memory and processing in computers.
As you consider utilizing carbon nanotubes and other graphene-related products, feel free to look through our catalog, where you can get a quote for purchase of CNT, graphene, or graphene oxide. And speaking of graphene oxide, be sure to check out our full write-up on graphene oxide.