Carbon Nanotube Primer: Your Guide To The Tiny Tubes That Could Revolutionize Computers, Medicine and Clothes

on September 27 2013 3:35 PM

A group of Stanford University researchers announced this week they had successfully built a working computer out of carbon nanotubes. This may lead you to ask: What?

 

 

Let’s start with the basics.

Carbon Tube Color A sheet of carbon molecules one atom thick (graphene) is rolled up into a tube.  Wikimedia Commons/Arnero

Carbon nanotubes are made of carbon, as you may have guessed. Sheets of hexagon-shaped carbon atoms are rolled up into a tube.

metallicseminanotube The properties of a carbon nanotube heavily depend on its particular twist.  Wikimedia Commons/timmymiller

The tube can have different properties, depending on what angle the tube is rolled at and how wide the tube is. An electric current will flow freely through a metallic carbon nanotube; in a semiconducting nanotube, there is an “energy gap” that requires a higher voltage to make the current flow.

It is also possible to build multiwalled carbon nanotubes, which are useful if you are manipulating the nanotubes with chemicals. With a double- or triple-layered nanotube, the chemical changes on the surface layer will change some of the bonds between the carbon atoms, leaving holes in the outer wall that can affect how the tube carries an electric current. But the unmodified inner wall will remain untouched.

So, what is the value of these structures, anyway? Carbon nanotubes are fantastically strong and stiff for their size, and they can conduct heat and electricity. Nanotechnologists are champing at the bit to try out these tiny fibrils in everything from computing to textiles. Some of the possible applications include:

‘Smart’ Clothes. Because nanotubes can conduct electricity, it could be easier than ever to seamlessly integrate electronics with clothing. You could hook up your Apple iPod to your jacket; athletes could wear heart monitors and other performance sensors right on their gear. Shirts could be rigged with detectors to sense allergens such as pollen or pollutants, as noted by the Discovery Channel via NBC News. In less flashier applications, carbon nanotubes could be used to make super-tear-resistant or super-water-repellent fabrics, as pointed out by Popular Science. Getting scalded by hot coffee dropped in the lap would be a thing of the past.

Synthetic Muscles. Scientists are working on making artificial muscles by spinning carbon nanotubes into a yarnlike shape. The result looks like the muscles found in a squid tentacle or elephant trunk. Once perfected, fake muscles could find their way into both robots and prosthetic limbs.

Recently, scientists figured out they could add even more brawn to their twisted tubes by infusing them with a paraffin wax, as recounted by Scientific American. When heated, the wax expands and the fake muscles can lift more than 100,000 times their own weight -- in contrast, an ant manages to lift just 100 times its own body weight, as reported by the Telegraph -- while generating 85 times the mechanical power of weakling mammals.

Medicine. Someday, you might be able to bring the doctor and the pharmacist along with you wherever you go. NASA has made a “biocapsule” out of carbon nanotubes that can detect illnesses and automatically deliver drugs. If you were a diabetic patient, you could have one implanted and never have to give yourself an insulin shot again. An astronaut’s biocapsule could instantly treat her for radiation poisoning if the sun flares up while she’s dangling off some Venus-orbiting spacecraft.

The biocapsule should be going into human trials within a few years, and, if all goes well, the International Space Station astronauts might be sporting them within the next decade.

Tiny Computers. So, now we’ve circled back to the carbon nanotube computer. It’s a particularly exciting frontier in computing, which until now has been based on silicon chips. The chip has a set of electronic circuits on top, made from transistors and other electronic components. Advances in design have allowed for smaller and smaller transistors, translating into smaller and smaller chips that provide faster and cheaper computing. But there is a lower bound to how small you can make a silicon chip -- with carbon nanotubes, you can go even smaller.

The Stanford-made carbon nanotube computer is relatively simple. It can run two simple programs at the same time, but running an early version of Windows would take millions of years, the creators told the New York Times.

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