What is Nanotechnology?
A nanometer (nm) is 10-9 meter. To put this in context, the dot over this letter "i" is approximately one million nanometers in diameter. Nanoscience is the study of phenomena on the nanometer scale (~1-100 nm). Nanotechnology is the ability to manipulate matter at the atomic, molecular or macromolecular level to create and control objects on the nanometer scale, with the goal of fabricating novel materials, devices and systems that have new properties and functions because of their small size. A nanomaterial is an object that has at least one dimension in the nanometer scale and include nanoparticles (three dimensions < 100 nm), nanotubes (two dimensions < 100 nm) and thin layers or coatings (one dimension < 100 nm).
What makes ‘nano’ special?
‘Nano’ means small, very small; but how is this special? The reason why nanoscience and nanotechnology are so promising in material, engineering and related sciences is that at the nanometer scale the properties of matter, like energy, change. The consequence is that a material when in a nano-sized form can assume properties which are very different from those when the same material is in a bulk form. For instance, bulk silver is non-toxic, whereas silver nanoparticles are capable of killing viruses upon contact. Properties like electric conductivity, colour, strength, weight, change when the nanoscale level is reached. This can be used to fabricate devices with very high power storage capabilities, or ultra-light materials that require little energy to operate.
Nanomaterials have an increased surface-to-volume ratio compared to bulk materials. This means that for a given volume of material, the external surface is greater if a nanomaterial is used rather than a bulk material. This is important for all those processes that use the material surface to perform certain operations, like catalysts in batteries or detection sites in sensors. Also, the higher surface-to-volume of nanomaterials allows to use less material, which has environmental and economic benefits, as well as fabricating highly miniaturized devices, which will use less power to operate and that can be portable.
Fabrication of nanomaterials can be done in two ways: building it ‘atom-by-atom’ (bottom-up approach) or by ‘carving’ the nanomaterial out of a bulkier one (top-down approach). The bottom-up approach aims at mimicking Nature’s way of assembling natural elements. By following a self-assembling method, scientist can create nanomaterials that have some very specific properties designed to correspond to very specific functions. For instance, the surface of a nanomaterial can be made with a molecular structure to detect a specific compound, such a metal. This allows to create detection devices that are very specific and accurate, with molecular-level precision.
What are the applications of nanotechnology?
Nanomaterials have some ‘special’ properties that can be exploited to fabricate new materials and devices and to improve existing ones. Nanotechnology allows fabricating devices using less material, improved specificity and accuracy, improved mechanical properties, such as strength, compression and wear resistance, reduced weight, enhanced durability, reduced toxicity and lower production costs. Nanotechnology applications include developing new sensors for environment and health monitoring; reducing pollution through air and water nanofilters; reduce emissions through improved fuel catalysis; improving existing devices like photovoltaic cells; developing new materials with exceptional strength, thermal properties, weight, permeability, colour; and developing miniaturized data storage devices that use less energy to operate.
A series of documents describing the current applications of nanotechnology can be found in the output section.