Discovery Science: Everyday Matter – Nanotechnology

Earth Science: Everyday Matter – Nanotechnology

Products made of nanomaterials are already being produced around the world. It is expected that nanoproducts of every shape and sort will be used more and more in our everyday lives in the years to come.

A nanometer is to a meter (equal to 3.2 feet) what the diameter of a hazelnut is to that of the Earth. Those who work with structures less than a hundred nanometers in size work in the world of nanotechnology, where classical principles of physics and chemistry do not always apply.

Today, research is primarily focused on nanostructured surfaces, nanoparticles, and the mixture of nanoparticles with materials such as plastic.

The creation of nanoparticles

Nanoparticles can be created by reducing structures and objects, a method that the semiconductor industry currently uses to miniaturize microchips. Objects can also be built by manipulating individual atoms and molecules.

Scientists use the tip of a scanning, tunneling microscope to move atoms to and fro, merging them into larger entities if needed. Because this procedure is time-consuming and costly, researchers are hunting for ways to get atoms and molecules to arrange themselves.

From sun protection to computers

Nanoparticles have already been added to many common substances, helping sunscreens deflect UV radiation, for example, and windshields to reflect heat and light; wafer-thin nanocoatings keep automobile paint and plastic glasses from scratching and mirrors from misting up. Nanostructured substances prevent dirt from gathering on self-cleaning bathtubs and roofing tiles.

Many nanotechnological discoveries will soon come into play in many areas of our lives. It is hoped that the surfaces of nanoparticles can be coated with biological matter that will allow nanocontainers loaded with poisons to attach themselves to cancerous cells. Nanostructures may also be able to suppress the formation of blood vessels that supply tumors.

Carbon nanotubes (atom-thick graphite sheets rolled into seamless cylinders) can be used to manufacture transistors and simple logical circuits that may soon replace silicon transistors, the miniaturization of which has reached its physical limits. Researchers today are investigating higher performance batteries, fuel cells, energy converters, and forgery-protected documents.

Properties of nanomaterials

Materials often change when shrunk to nanoscale. Gold, which has a distinctly yellow color and very low chemical reactivity, turns red at the nanoscale and acts as a catalyst,
accelerating reactions between other sub- stances.

This is because the proportion of its surface area to its volume changes, a fundamental principle of nanotechnology. The greater the surface area, the greater the possibility of chemical and physical exchange with the environment.

CARBON NANOTUBES

Nanotubes are tiny tubes with a diameter of only a few nanometers and a length that can be up to one millimeter. By comparison, a human hair is 50,000 times thicker. Particularly well researched are carbon nanotubes (CNTs), but there are also nanotubes made of other substances.

Carbon nanotubes are built up from one or several graphite layers that are rolled cylindrically. They can be single or multi-walled, and depending upon production conditions, bundles or threads of nanotubes can also occur.

Nanotubes conduct heat very well and, according to their structure, they can be good semiconductors or even superconductors at certain temperatures. Moreover, they do not tear and they are extremely stable against chemical and thermal influences.