Nanotechnology is not only about small scale. As objects become smaller than 100 \(nm\), their physical and chemical properties change. This is a direct result of the fact that the surface-to-volume ratio increases, and surface effects start to dominate. If you consider a cube of 1 \(m\) in size, you can calculate its volume to be 1 \(m\)\(3\) and its surface to be 6 \(m\)\(2\) (i.e. 6 sides each being 1 x 1 \(m\)). Now imagine that you cut this cube into smaller cubes, each one being 1 \(nm\) in size. This will result in 1027 cubes having the same volume (or mass) as the large 1 \(m\) cube, but having a total surface area of 6×1027 \(nm\)\(2\). Furthermore, as particles are smaller and become nanometer-sized, quantum mechanical effects become noticeable. Part of a stained-glass window from the Sint-Jans Church in Gouda, The Netherlands (source Wikipedia)(Click to expand)A simple but very intriguing example of changing properties as materials are on the nanometer scale is the apparent color of nanoparticles. Depending on the size and shape of gold particles in an aqueous solution, the color of the liquid is different. This property has been used for thousands of years for creating stained glass. “Nano Flowers”, bar 5 \(\mu m\)In the late 20th century, research started to shift its attention from micrometer-sized objects to the nanometer-scale. This change was realized by the great advances made in different scientific fields. The main catalyst of nanotechnology is the development of new nanoscopic techniques, such as scanning tunneling microscopy (STM) and transmission electron microscopy (TEM), discussed in more detail in step 1.7. These techniques allowed scientists to study objects that could not be studied before, such as individual molecules, surfaces and crystal structures of materials with atomic resolution. Scientists are now able to study electrical, magnetic, chemical and biological properties on this small scale. These possibilities spurred an avalanche of new research and developments, which is still ongoing today. We are only at the brink of many new scientific and technological developments, now that we are getting more and more experienced with this nanoworld and all the possibilities it offers.
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