Nano Tubes? Whats a Nano Tube?
Carbon at its Smallest
Amazing material but could they be "tomorrows asbestos"?
Now for those of you who who are Stargate fans we are not building Replicators. We are talking about tiny tubes made of rings of carbon atoms like the picture to the right. These nanotubes are the strongest fibers known. A single perfect nanotube is about 10 to 100 times stronger than steel per unit weight
There are four primary types of nanotubes: Membrane, DNA, Inorganic and Carbon. The membrane nanotube is formed from the plasma membrane in animal cells to facilitate communication between cells. DNA tubes are a basic type that can commonly be modified to make other things, like carbon nano tubes. The Inorganic variety is often composed of metal oxide or titanium dioxide and can be used for a number of industrial uses. Lastly, the real superstar -- Carbon tubes - are the most useful in practical applications but may potentially be the riskiest in the long run.
Researchers have discovered that carbon nanotubes in mass quantities can have a number of vital nanotechnology applications. Using large nanotube sheets, these nano-sized superstars can conduct electricity, emit light or heat, absorb solar power, create more flexible surfaces, provide even light distribution and strengthen sails. "When you have a remarkable material, it's easy to make advances in terms of applications," said head researcher Ray Baughman at the University of Texas, Dallas. Truly, carbon nano tubes are the way of the future.
To create a string of nanotubes, scientists assemble trillions of strings of individual carbon nano tubes, which are comprised of cylindrical sheets of carbon atoms. In the past, nano sheets were made much like paper is made, by filtering solutions full of nano tubes, peeling the nanomaterials off and letting them dry for a week. Today, lab workers can grow nano forests of bundles stacked vertically, drawing numerous tiny tubes to sheets of duct tape, producing seven meters of sheets per minute. Ray Baughman explains: "A trillion nano tubes must be automatically rotated by about 90 degrees and self-assembled in a parallel fashion for every meter-long, 7 centimeter-wide sheet that we make."
Nanotubes comprised of carbon are among the most promising nanomaterials, according to Enrico Bergamaschi of the University of Parma Medical School. Despite their innovative properties, the tiny size of carbon tubes may have detrimental effects that we are unaware of. Nanoscience has only been around for 20 years, so there really hasn't been the opportunity to complete a study of long-term exposure to the particles. Potential dangers, he warns, are that small particles will remain in the lungs or other organs for extended periods unless combined with other chemical groups, which reduces cytotoxicity. Bergamaschi says, "As more of these materials are produced, there is an urgent need to refine strategies to assess their possible effects on employees who represent the main exposed population, along with characterizing exposure, so that appropriate safety regulations can be put in place if needed."