Nanotechnology Overview
Simply defined, nanoscience is the study of unique properties of matter that occur at the nanoscale (lengths of roughly 1 to 100 nanometers - or one billionth of a meter). The application of nanoscience is called nanotechnology. A National Science Foundation official has more precisely defined nanotechnology as a science that deals with materials and systems that have these key properties:
- At least one dimension is from one 1 to 100 nanometers;
- The process of their design uses fundamental control over the physical and chemical attributes of molecular-scale structures; and
- They can be combined to form larger structures1.
Since the properties of matter depend in part on size, the physical, chemical and biological properties of matter generally differ at the nanoscale when compared to larger quantities of the same material. This is due, in part, to the difference in surface area per unit of volume at the nanoscale.
For a given material, increasing the number of nanoscale particles increases the proportion of atoms on the surface compared with the number of internal atoms. Atoms at the surface often behave differently from those located in the interior since they have a higher energy state. The result is that more chemical reactions can take place between atoms and molecules at the surface. Essentially, nanoscale particles act as miniature chemical reactors.
In addition, other properties such as magnetism, hardness and electrical and heat conductivity can be changed substantially by modifying materials at the nanoscale. These changes arise from surprising collective and quantum size effects that arise from confining electrons in nanometer-sized structures.
References:
Stix, G., Little Big Science. Scientific American, September 2001; 32-37 ↑
