Carbon nanotubes

Bruno CalzaWilliam Sather

Presentation Overview

• What is it?

• Applications

• Characteristics

• Nano vs. Macro

• Concerns

• Conclusions

• References

What is it?• Carbon nanotubes are

allotropes of carbon• A single wall carbon nanotube

is a one-atom thick sheet of graphite rolled up into a seamless cylinder with diameter of the order of a nanometer

• Discovered in 1991 by S. Iijima

Applications• Clothes: waterproof tear-resistant

cloth fibers • Combat jackets: carbon nanotubes

as ultra strong fibers and to monitor the condition of the wearer

• Concrete: CNTs increase the tensile strength

• Polyethylene: CNTs increase the polymer's elastic modulus by 30%

• Sports equipment: stronger and lighter

• Ultrahigh-speed flywheels: the high strength/weight ratio enables very high speeds to be achieved

BST6 - 2007 Easton Stealth CNT

Regular Flex

Applications• Space elevator: this will be

possible only if tensile strengths of more than about 70 GPa can be achieved. Monoatomic oxygen in the Earth's upper atmosphere would erode carbon nanotubes at some altitudes, so a space elevator constructed of nanotubes would need to be protected (by some kind of coating). Carbon nanotubes in other applications would generally not need such surface protection.

Applications• Chemical nanowires: can also be

used to produce nanowires of other chemicals, such as gold or zinc oxide

• Computer circuits: there is a possibility to build electronic computer circuits entirely out of nanotubes

• Conductive films: CNTs are ideal for high reliability touch screens and flexible displays

• Light bulb filament: alternative to tungsten filaments in incandescent lamps

• Magnets: MWNTs coated with magnetite

• Ultra capacitors: increase in energy storage ability

MC and BC series supercapacitors (up to 3000 farad capacitance) produced by Maxwell Technologies

Applications• Electric motor brushes: nanotube composite motor

brushes are better-lubricated, cooler-running, less brittle, stronger and more accurately moldable.

• Optical ignition: a layer of 29% iron enriched SWNT is placed on top of a layer of explosive material and can be ignited with a regular camera flash.

• Superconductor: nanotubes have been shown to be superconducting at low temperatures

• Displays: high-brightness low-energy low-weight displays can be made

Applications• Air pollution filter: future applications of nanotube

membranes include filtering carbon dioxide from power plant emissions

• Biotech container: nanotubes can be opened and filled with materials such as biological molecules, raising the possibility of applications in biotechnology.

• Hydrogen storage: there is potential to contain the same quantity of energy as a 50l gasoline tank in 13.2l of nanotubes.

• Water filter: the tubes are so thin that small particles (like water molecules) can pass through them, while larger particles (such as the chloride ions in salt) are blocked.

Applications• Oscillator: fastest known oscillators (>

50 GHz) • Liquid flow array: liquid flows up to

five orders of magnitude faster than predicted through array

• Slick surface: slicker than Teflon and waterproof

• Transistor: “Carbon nanotube transistors have the potential to outperform state-of-the-art silicon devices,” said Dr. T.C. Chen, vice president, Science & Technology, IBM Research. “However, scientists have focused so far on fabricating and optimizing individual carbon nanotube transistors. Now, we can evaluate the potential of carbon nanotube electronics in complete circuits -- a critical step toward the integration of the technology with existing chip-making techniques.”

A close-up view of the 5-stage CMOS type nanotube ring oscillator. The upper right

inset shows the nanotube itself with a diameter of ~2nm.

Characteristics• Extraordinary strenght:

200 times stronger than steel

• Unique electrical properties: mettalic nanotubes can have an electrical current density more than 1,000 times greater than metals such as silver an copper.

• They are efficient conductors of heat

• Very light

Nano vs. Macro

• Carbon nanotubes are much stronger and lighter than the carbon (allotropes) and can conduct electricity and heat.

• The reason for this is the symmtrical shape and strong bonds between the carbons

CNT density 1.3-1.4 g/cm³

Diamond density

3.513 g/cm³

CNT Thermal Conductivity 6000 W/m/K

Graphite Thermal Conductivity

(119-165) W/m/K

Concerns• Carbon nanotubes injected directly into bloodstream of research lab

animals cause no immediate adverse health effects and circulate for more than one hour before they are removed by the liver. More studies are being made about its toxicity.

• People are confused about it. They don’t know if it is fact or fiction. This confusion makes them fear this new discipline.

• Single-walled nanotubes are still very expensive to produce, around 1500 $ per gram

Conclusion• This is the future of the world. It may provide new solutions

for the millions of people in developing countries who lack access to basic services, such as safe water, reliable energy, health care, and education.

• Everthing will become stronger, smaller and lighter.

The joining of two carbon nanotubes with different electrical properties to form a diode has been proposed.

References• Who should be given the credit for the discovery of carbon nanotubes? CARBON 44 (2006)

1621 (ELSEVIER) Retrieved May 17, 2007, from http://en.wikipedia.org• Philip G. Collins and Phaedon Avouris (2000), Nanotubes for Electronics - Scientific

American December 2000, page 67 Retrieved May 17, 2007, from http://en.wikipedia.org• Super-tough carbon-nanotube fibers Alan B. Dalton et al. Nature 423, 703 (12 June 2003)

Retrieved May 17, 2007, from http://en.wikipedia.org• Azad Naeemi and James D. Meindl (2007,). "Carbon nanotube interconnects". ISPD '07:

Proceedings of the 2007 international symposium on Physical design,: 77--84,, {Austin, Texas, USA},: ACM Press, New York, NY, USA. Retrieved May 17, 2007, from http://en.wikipedia.org

• S. Sen, I.K. Puri, Nanotechnology 15, 264-268 (2004). Retrieved May 17, 2007, from http://en.wikipedia.org

• The Space Elevator, by Brad C. Edwards, NASA Retrieved May 17, 2007, from http://en.wikipedia.org

• Dekker, Postma et al (2001), Carbon Nanotube Single-Electron Transistors at Room Temperature - Science 293.5527 (July 6, 2001) Retrieved May 17, 2007, from http://en.wikipedia.org

• Avouris, Arnold, Collins Engineering Carbon Nanotubes and Nanotube Circuits Using Electrical Breakdown - Science 292.5517 (April 27, 2001):706-9 Retrieved May 17, 2007, from http://en.wikipedia.org

• Kalaugher Scalable Interconnection and Integration of Nanowire Devices Without Registration Nano Letters 4.5 (2004):915-19 Retrieved May 17, 2007, from http://en.wikipedia.org

• Tesng et alMonolithic Integration of Carbon Nanotube Devices with Silicon MOS Technology Nano Letters 4.1 (2004):123-127 Retrieved May 17, 2007, from http://en.wikipedia.org

References• Kalaugher Scalable Interconnection and Integration of Nanowire Devices Without

Registration Nano Letters 4.5 (2004):915-19 Retrieved May 17, 2007, from http://en.wikipedia.org

• Tesng et alMonolithic Integration of Carbon Nanotube Devices with Silicon MOS Technology Nano Letters 4.1 (2004):123-127 Retrieved May 17, 2007, from http://en.wikipedia.org

• Nanotubes Tracked In Blood And Liver: Study Finds No Adverse Effects Retrieved May 17, 2007, from http://scienceandreason.blogspot.com/2006/12/do-carbon-nanotubes-present-health.html

• Health, safety, environmental and social issues Retrieved May 17, 2007, from http://www.nanotec.org.uk/workshopOct03health.htm