简体中文When Will Carbon Nanotubes Save The World?
Carbon nanotubes have been around for decades, but they've yet to make a significant impact among the public at large. What's the deal? When are these light, strong microscopic filaments going to change the world? Some would say they already have. Here are a couple new ways researchers are using carbon nanotubes to make our world more awesome.
In a computer system, if one copper wire fails to transmit the electrons the whole system can fail. While most research is focused on producing carbon nanotubes efficiently and cheaply, researchers at National Institute of Standards and Technology (NIST) are exploring their actual use in technological application.
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As electronics get smaller, manufacturers search for ways to save space. Nanotubes are a possible way to miniaturize the connections between components. Aside from their small size, the filaments themselves "offer big promise in a small package," said Science Daily, "These tiny cylinders of carbon molecules theoretically can carry 1,000 times more electric current than a metal conductor of the same size."
Science Daily continues, "it's easy to imagine carbon nanotubes replacing copper wiring in future nanoscale electronics." However, Thomas Edison tried carbon filaments while working on the lightbulb, and though they were not nano-sized they burned out too quickly. Unfortunately for the researchers trying to replace copper, their nano brothers experienced the same problem.
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"The common link is that we really need to study the interfaces," says Mark Strus, a NIST postdoctoral researcher. The interfaces are the connections between nanotubes as well as the connections between nanotubes and other metals.
Exploration in this area is sparsely researched, and the results will help press the nanotubes into electronics service once their creation is affordable.
Unfortunately, the researchers' determinations were not promising for the replacement of copper in chips because as "metal electrodes fail — the edges recede and clump — when currents rise above a certain threshold. The circuits failed in about 40 hours," said Science Daily.
Though the nanotubes seem ill-fitted for computer chips, Mark Strus, another NIST postdoctoral researcher, said, "Carbon nanotube networks may not be the replacement for copper in logic or memory devices, but they may turn out to be interconnects for flexible electronic displays or photovoltaics."
Outside of the NIST project, other researchers are looking for nanotubes to function as more efficient biosensors.
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Biosensors use electrodes coated with enzymes to "sense" certain compounds. When the compounds are present the enzymes react, creating a measurable electrical signal. Current systems work, if imperfectly, and nanotubes might be able to revolutionize this field too. Scientists at Purdue University are exploring carbon nanotubes for these new biosensors.
To make the nanotubes compatible with the process, they must first make them compatible with water. To solve the problem, professors Marshall Porterfield and Jong Hyun Choi created synthetic DNA that attaches the nanotubes in a solution.
"In the future, we will be able to create a DNA sequence that is complementary to the carbon nanotubes and is compatible with specific biosensor enzymes for the many different compounds we want to measure," Porterfield said. Choi continued, "Once the carbon nanotubes are in a solution, you only have to place the electrode into the solution and charge it. The carbon nanotubes will then coat the surface,"
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The floating tubes will indicate the presence of the specific enzyme which can be measured and reported externally.The sensor described in the findings is designed for glucose, however, the technology can be adapted for other compounds.
"You could mass produce these sensors for diabetes, for example, for insulin management for diabetic patients," Porterfield said.
While nanotubes are still in the research phase, they've come a long way from their discovery and mass creation. Once they can be cheaply produced, research like this will help us press them into service around the scientific and technological worlds.
Source: PhysOrg, Science Daily
Image: Corbis