Applications

With their unique tenacity, strength and stiffness, nanotubes are often incorporated into other materials to reinforce their structures and increase the material's strength. The incorporation of nanotubes into the materials forn nanocomposites, which is a new yet promising class of structural materials for a variety of applications. One such application of is its use in the mechanical components of microelectromechanical systems (MEMS).

Single wall nanotubes are used to store gases, in particular Hydrogen, through physisorption and chemisorption mechanisms. Nanotubes are capable of easily absorbing and releasing large quantities of hydrogen. In light of the impending energy crisis as fossil fuels grow scarce, hydrogen is a possible alternative energy carrier, and scientists are researching means of producing and storing hydrogen in electric power plants.

The polymer shell (blue) wraps around a semiconducting single-walled carbon nanotube (red).

Carbon nanotubes can be either conducting or semi-conducting, depending on their structure and methods of synthesis.

Semiconducting nanotubes can be used in flexible transistors for circuits printed on flexible plastic displays and stretchable electronics. They can also be used to bridge gaps in solar cell technology. On the other hand, conducting tubes are used widely in wires and electrodes.

Conducting Plastics

Anti-fouling Paint

Multi-wall CNT liquid dispersions based on silicone resins have been designed for eco-friendly fouling release systems in marine coating applications, such as ship hulls and oil rigs.

Carbon nanotubes can be incorporated into organic light emitting diodes to create larger flat screen displays that are cheaper to manufacture than their silicone counterparts. Carbon nanotubes are some of the best conductors of charge ever discovered, and are also chemically / mechanically robust and able to withstand stress without breaking. Transistors built from carbon nanotubes could enable displays of the future to flex and bend.

Flat-panel Displays

Gas Storage

Current Applications

Carbon Nanotube Technology can be used for a wide range of new and existing applications:

Micro/Nano Electronics

Biosensors

Extra Strong Fibres

Batteries with improved Lifetime

Ultra-capacitors

Technical Textiles

Radar-absorbing coating

As silicon-based microelectronics follow Moore's Law, they have a limit to miniaturization. Carbon nanotubes create room for further miniaturization as long as it is possible to selectively deposit them with defined properties.

Carbon nanotubes are being explored for use in medical applications as biosensors. Thus far, a microbial biosensor based on CNT modified electrodes has been developed.

Carbon nanotubes absorb an extremely broad spectrum of light, and this would enable them to cloak objects from visible light and radar. In order to ensure that the nanotubes neither reflect nor scatter any light, the nanotubes have to be grown with some space in between them so their refraction index is very similar to that of the surrounding air. This keeps light from scattering out of the little forests of nanotubes without being absorbed, but it's also kind of painstaking. The nanotubes can then be used to coat stealth objects e.g. aircrafts.

Carbon nanotube based fibers are being investigated as a possible alternative to traditional copper wires. On a pound-per-pound basis, carbon nanotube-based fibers invented at Rice University have greater capacity to carry electrical current and are stronger than copper cables of the same mass.

Early last year, researchers unveiled a new CNT fiber that conducts heat and electricity like a metal wire, is very strong like carbon fiber, and is flexible like a textile thread.The new CNT fibers have a thermal conductivity approaching that of the best graphite fibers but with 10 times greater electrical conductivity. While graphite fibers are brittle, the new CNT fibers are as flexible and tough as a textile thread. This combination of properties can lead to new products with unique capabilities for the aerospace, automotive, medical and smart-clothing markets.

Carbon nanotubes are set for use in making of flexible batteries which would allow for flexible displays on portable electronic devices.

Carbon nanotube / graphene supercapacitors, microscale flexible energy storage devices, were unveiled earlier this year and can store enough energy to rival the gold standard, lithium batteries. That’s significant because the device is actually not a battery, it is a supercapacitor that can charge and discharge much faster than a battery.The carbon nanotube/ graphene supercapacitor hybrid fiber is self-assembled through the following process: A solution containing acid-oxidized single-wall nanotubes, graphene oxide and ethylenediamine, which promotes synthesis and dopes graphene with nitrogen, is pumped through a flexible narrow reinforced tube called a capillary column and heated in an oven for six hours. The advantage of this structure is the enormous amount of available surface area for both energy storage and charge conduction, clocking in at a whopping 396 square meters per gram of fiber.

Fabrics made entirely of carbon nanotubes have many potential applications. One of the most attractive is in high-strength composite materials. Fabrics with long, aligned, individualized CNTs can be used to produce resin pre-impregnated fabrics and high-fiber volume fraction composite materials with morphologies that resemble traditional carbon fiber materials.

With the multifunctional properties they would provide, CNT fabrics and composites produced from them may fill needs not met by carbon fiber composites in defense, aerospace, automotive and consumer markets. Their high specific surface area, chemical stability and thermal stability make them a great candidate for battery electrodes, catalyst supports, thermoelectric materials, and air and water filtration.

Potential Applications

Due to its unique and interesting properties, carbon nanotubes have many potential applications.

The strength and flexibility of carbon nanotubes makes them of potential use in controlling other nanoscale structures, which suggests they will have an important role in nanotechnology engineering.

Structural Composite Materials

The brightness of field-induced polymer electroluminescent technology can be enhanced and improved using multiwalled carbon nanotubes. This has large potential in the development of a pleasing, safe, and high-efficiency lighting without the mercury vapor or the bluish tint that are problems that other lighting sources often face.

Elastic potential energy can be stored in a CNT by deforming it under an applied load. Removal of the applied load will cause energy to be released, wich can be harnessed for mechanical work.

Carbon nanotube springs are predicted to have the potential to indefinitely store elastic potential energy at ten times the energy density of lithium-ion batteries, and with flexible charge and discharge rates. The ability of CNTs to deform reversibly with little fatigue allows for extremely high cycling performance.

A paper battery synthesized from a thin sheet of cellulose infused with aligned CNTs. The nanotubes are used as electrodes in the paper batteries to allowing conduction of electricity within the device. A long, steady power output similar to a conventional battery can be achieved by paper batteries. This, coupled with the paper battery's ability to have quick bursts of high power, allows it to function as both a lithium-ion battery and a supercapacitor. It is thus highly energy efficient.

Lighting

Carbon Nanotube Springs

Paper Batteries

A nanosponge can be formed using carbon nanotubes, sulfur and iron, which has been shown to be more effective at soaking up water contaminants like fertilizers, pesticides, oil and pharmaceuticals. The sponges are superhydrophobic and oleophilic, thus allowing then to effectively absorb oil while remaining on the water surface. The nanosponges are also easy to retrieve from the water due to their magnetic properties.

Sheet of nanotubes have the potential to operate as a loudspeaker with the application of an alternating current. The sound is then generated thermoacoustically.