What is nanotechnology?
The term ‘Nanotechnology’ (from the Greek word ‘nano’ : dwarf) is used when some feature is produced or exploited in the range 1-100 nanometres (nm). Nanomaterials exist all around us in nature and have been produced by ‘accident’ in ancient glassmaking (eg red colouration in Roman glass from addition of gold as in the Lycurgus Cup ). However, major developments in the last 20 years which have allowed us to manufacture, analyse and image at the nanoscale with great precision, and have moved nanotechnology from an ‘art’ to a ‘science’.
There have been many attempts to define nanotechnology. One of the most cited definitions was put forward by the Working Group set up by the Royal Society and Royal Academy of Engineering. The group distinguished between nanoscience, which is the study of phenomena at the very small scale, and nanotechnology, which implies an aim to achieve an end that is in some way useful: Nanoscience is the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at larger scale. Nanotechnologies are the design, characterization, production and application of structures, devices and systems by controlling shape and size at nanometre scale.
Lots of interesting effects come into play when one starts to look at matter at very fine dimensional scales. These include high chemical reactivity, increased mechanical strength and quantum phenomena. These have led to a diverse range of applications in electronics photonics, in the development of new strong materials and in biomedicine.
The breadth of nanotechnology has led to some criticism that it is “all things to all men”, and therefore cannot be called a subject at all. However, it is this diversity that makes the subject fascinating and is leading to new cross-disciplinary applications, where nanoscale effects in one traditional discipline are being exploited in another.
Some nanomaterials and nanocoatings are now produced as ‘commodities’ (eg carbon nanotubes for conductive fillers or medical sensors, titanium dioxide for UV absorption in suncream). However, most nanomaterials are produced as custom products to achieve some specific additional functionality. Nanostructuring can produce beneficial properties eg nanoporous polymers for supercapacitors, or tough nanostructured ceramics. Nanocoatings such as diamond-like carbon are giving engineers new methods for combating friction and wear, as well as invisible conductive layers for switchable glass, and improved solar cells. Silicon wafer processing is now using techniques such as focussed ion beam etching and epitaxial growth to achieve features less than 100 nm leading to the higher processing power and the high capacity memories we now take for granted in our electronic devices. Healthcare is a key sector which is investing heavily in nanotechnology for disease detection and treatment.
The potential hazards that might be associated with nanotechnology and nanomaterials were studied by the Royal Society / Royal Academy of Engineering Working Group. In the report they concluded that, while there was no immediate cause for concern, that there was insufficient knowledge about the potential risks associated with exposure to nanomaterials. The IOM3 Nanomaterials and Nanotechnology Committee is keen to promote the study and acquisition of knowledge in this area.
So, although nanotechnology may be ‘invisible’, it is increasingly being used to enhance and invent products in areas as diverse as healthcare, energy, transport, buildings, communications and space exploration. As Richard Feynman predicted in 1959 – ‘There’s plenty of room at the bottom’.