Nanotech 101
Lab-on-a-chip incorporates carbon "nanowires," shown here as a thin white line across this image, one-thousandth the width of a human hair. (Image courtesy of Nongjian Tao)
Earth & Sky’s Eleanor Imster explains the basics:
My son’s eyes light up when he hears the word nanotechnology. To him, nanotech is a fantasy of invisibly tiny robots. But mention nanotech to most adults, and you’re likely to get either a blank look or a polite comment like, “Isn’t that something about computers?”
Scientists, politicians and businessmen tell us that nanotechnology will totally change our world. So what exactly is it?
What makes something “nano” is its size. Nanotech deals with things so small that they’re measured in “nanometers.” A nanometer is one–billionth of a meter.
Just how small is that? It’s invisibly tiny. A particle tens of thousands of nanometers in length is still much, much too small for us to see. A conventional microscope can’t detect individual molecules that are a few nanometers in diameter. A slice of a single strand of hair – sliced across like salami – would measure about a hundred thousand nanometers across.
Some people have long suspected that a world exists that’s too small to see. But within the past couple of decades, new tools, such as the atomic force microscope, have allowed scientists to replace models and calculations about the nanoscale world with an actual ability to see that world and manipulate it.
And it turns out that materials act profoundly differently when they’re at nanoscale–smaller than about 100 nanometers in length, still far far tinier than the thickness of a strand of hair. At this scale, a material’s properties change–things like electrical conductivity and mechanical strength are not the same as they are at bulk size.
Consider the element carbon at the nanoscale. In nature, when carbon atoms are arranged one way you get a diamond. If they’re put together another way, you get graphite. In recent years, nanoscientists have learned to arrange carbon atoms in yet another way: into tiny tubes about two nanometers in width that can look like chicken wire and can grow to a length many times their diameter. These carbon nanotubes are a brand new material. It’s still the element carbon. But the carbon nanotube is a completely different material from either diamond or graphite. Scientists are currently exploring the properties of these nanotubes.
The power of nanotech is in the manipulation of materials at the nanoscale. This manipulation enables scientists and engineers to alter the properties of materials to do make them do new things. It lets them invent materials not found in nature.
There are many potential applications for nanotechnology. And there are safety concerns. As these materials become part of our world, what will be their postive and negative impacts on our environment and health? According to Dr. George Malliaras, a nanoscientist at Cornell University, “It’s not understood by any means. and since their properties are different from that of the bulk material . . . this is something you have to study.”
In the coming years, with funding from many different organizations, scientists will be doing just that.
