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Images: Making Nanotubes Without Harming the Environment

Carbon nanotubes have been hailed as a new ?wonder material? whose remarkable strength, durability, and ability to conduct electricity and heat can be exploited for a wide variety of industrial uses. They are made of carbon atoms arranged as flat sheets in hexagons. Now imagine the flat sheets are rolled into slim cylinders, or tubes, whose lengths (measured in micro- or millimeters, or millionths or thousandths of a meter) greatly exceed their width (measured in nanometers, or billionths of a meters). (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)

A scanning electron microscope image shows carbon nanotubes aligned vertically like trees. Scientists often refer to such aggregations of nanotubes as "forests." (A. John Hart, University of Michigan)

Here's a "forest on a finger." Carbon nanotubes are engineered at the atomic level into cylindrical structures made of carbon (similar to those found in graphite, the material in No. 2 pencils). The nano-sized arrangement gives them unusual and useful properties for industrial applications. These types of nanotubes could appear in your TV, laptop, or cell phone someday. Some nanotubes are already used to strengthen sailboats, tennis rackets, and bicycles. (A. John Hart, University of Michigan)

MIT/WHOI graduate student Desiree Plata uses a flame torch to seal samples for carbon isotope measurements for her lab experiments. Her research, published March 21, 2007, in the journal Nanontechnology, showed that differently manufactured carbon nanotubes have distinctive chemical characteristics ?making it more difficult to track them in the environment. (Photo by Kristin Pangallo, MIT/WHOI)

Plata and her Ph.D. advisors, environmental chemists Phil Gschwend of MIT (left) and Chris Reddy of WHOI (seen here deploying a submersible pump aboard the R/V Cape Hatteras in 2004) seek to work proactively with industry during the nanotube manufacturing design phase to develop methods that preempt potential environmental dangers and maximize the safe use of new materials. (Photo by Bob Nelson, Woods Hole Oceanographic Institution)

In earlier experiments, Plata showed that the carbon nanotube synthesis process produced several cancer-causing compounds and substances that can contribute to ozone and smog formation, both of which cause respiratory ailments. This reactor, known as a tube furnace, is used to manufacture, or "grow," carbon nanotubes. The QFF is a quartz fiber filter used to collect particles produced by the manufacturing process. The PUF is a polyurethane foam used to collect hydrophobic compounds, like the polycylic aromatic hydrcarbons(PAHs). The gas cannister collects gases that come out of the heated quartz reactor tube, where nanotubes "grow." (Photo by Desiree Plata, MIT/WHOI)

In her experiments, Plata used polyurethane foam (PUFs) to filter gaseous byproducts of carbon nanotube production. The bottom PUF is new; the top one has done its filtering job. Its yellow color comes from chemical compounds similar to the carcinogens found in cigarette smoke. (Photo by Desiree Plata, MIT/WHOI)

In research published in Nanotechnology, the MIT/WHOI researchers showed that different commercially produced carbon nanotubes have different chemical characteristics. The solutions above, obtained from nanotubes, have different colors because they were fabricated using different metals. (Photo by Desiree Plata, MIT/WHOI)