Link List: Materials Science In Action

by Brock on March 17, 2008

Over dinner and a beer a couple of weeks ago, my friend jokingly asked me “What’s new in the world of Material Science?”

He may have been joking, but I’ve read a couple of interesting Materials Science-related news stories recently, so I thought I would share some of them with you. Considering how often people ask me, “What’s Materials Science?”, I thought it would be a good idea to educate my readers on the subject.

All of these stories share a common theme: carbon nanotubes. Nanotechnoloy is the hottest buzzword in Materials Science (and any other discipline) these days, and carbon nanotubes are a big part of the nanotech world.

  • “None more black” - Beginning with a great quote from Spinal Tap, this article reports on the recent creation of the darkest known material by researchers at Rice University and RPI. How does one make a blacker black? By using a material that reflects less light. Researchers did this by densely packing carbon nanotubes standing on end like bristles on a toothbrush. This arrangement traps light very efficiently and could have some useful applications.
  • Nano-powered clothes - Researchers at Georgia Tech have developed a fabric that converts motion into energywhich could be used to power small, portable electronic devices. The idea here isn’t exactly new: certain materials (usually crystalline materials like metals) will produce an electric potential in response to an applied stress. Such materials are called piezoelectrics. In this case, piezoelectric nanowires are grown on textile fibers. The nanowires grow out radially from the fibers like spokes on a wheel. If such a textile were used to make clothing, the motion of a person wearing the clothing would cause the fibers to rub back and forth against each other causing the nanowires to bend this way and that (that’s the applied stresspart) which would create electricity. The power generated in this way is small but it still has a lot of useful applications. (click here for National Geographic’s report on the story).Incidentally, piezoelectrics can work the opposite way, too: an applied electric field can generate stress in the piezoelectric material. Stress leads to strain in the material (i.e., deformation). What this all means is that you can change the shape of a solid material using electrical signals. This has lots of interesting applications like airplane wings or marine vessels that change shape without moving parts, or valves that open and close in tiny fluid channels (something my research deals with).
  • Carbon bedsheet - Nanotubes are basically rolled up sheets of graphite (i.e., pencil lead). They have a very high aspect ratio meaning they are much longer than they are wide, and they posses many interestingproperties such as exceptional strength, and unique electrical, thermal and optical properties. A major obstacle to making nanotubes commercially useful is the difficulty in incorporating them into large structures. But a company in New Hampshire, Nanocomp Technologies, has now made the world’s largest sheet of carbon nanotubes. The sheet is flexible and can be cut with scissors, yet it is stronger than steel while being 30 times less dense.
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