Nanotechnology – The major frontier area of science and technology………

We can define nanoscience as the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale; and nanotechnologies as the design, characterization, production and application of structures, devices and systems by controlling shape and size at the nanometer scale. Definition, the design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometer scale (atomic, molecular, and macromolecular scale) that produces structures, devices, and systems with at least one novel/superior characteristic or property.

History :…….

•      Carbon Nanotubes (first observed by  Sumio Iijima in 1991.).
•    Inorganic nanotubes and inorganic fullerene-like materials based on layered compounds such as molybdenum disulphide were discovered shortly after CNTs.
•     Nanowires are ultrafine wires or linear arrays of dots, formed by self-assembly (e.g., semiconductor nanowires made of silicon).
•    Biopolymers -  variability and site recognition of biopolymers, such as DNA molecules. 
•     Nanotechnologists claim that the combination of one-dimensional nanostructures consisting of biopolymers and inorganic compounds opens up a number of scientific and technological opportunities.

Reasons for the difference in the properties : (at the nanoscale) First, nanomaterials have a relatively larger surface area when compared to the same mass of material produced in a larger form. This can make materials more chemically reactive (in some cases materials that are inert in their larger form are reactive when produced in their nanoscale form), and affect their strength or electrical properties.  Second, quantum effects can begin to dominate the behavior of matter at the nanoscale - particularly at the lower end - affecting the optical, electrical and magnetic behavior of materials. Materials can be produced that are nanoscale in one dimension (for example, very thin surface coatings), in two dimensions (for example, nanowires and nanotubes) or in all three dimensions (for example, nanoparticles).

Current applications of nanoscale materials include very thin coatings used, for example, in electronics and active surfaces (for example, self-cleaning windows). In most applications the nanoscale components will be fixed or embedded but in some, such as those used in cosmetics and in some pilot environmental remediation applications, free nanoparticles are used. The ability to machine materials to very high precision and accuracy (better than 100nm) is leading to considerable benefits in a wide range of industrial sectors, for example in the production of components for the information and communication technology, automotive and aerospace industries.

Current Applications (success achieved to some extent):

• Sunscreens and Cosmetics (nano sized titanium dioxide and zinc oxide-which absorb and reflect ultraviolet (UV) rays and yet are transparent to visible light).
• Composites (carbon black used as a filler to reinforce car tyres).
• Clays  (nano-sized flakes of clay- use in car bumpers).
• Coatings and Surfaces (e.g., self-cleaning window : coated with  highly activated titanium dioxide, engineered to be highly hydrophobic (water repellent) and antibacterial, and coatings based on nanoparticulate oxides that catalytically destroy chemical agents.)
• Tougher and Harder Cutting Tools [tungsten carbide, tantalum carbide and titanium carbide, are more wear and erosion-resistant, and last longer than their conventional (large-grained) counterparts].

Future of Nanotechnology: Although present ones represent incremental developments, surfaces with enhanced properties should find applications throughout the chemicals and energy sectors. The benefits could surpass the obvious economic and resource savings achieved by higher activity and greater selectivity in reactors and separation processes, to enabling small-scale distributed processing (making chemicals as close as possible to the point of use). There is already a move in the chemical industry towards this. Another use could be the small-scale, on-site production of high value chemicals such as pharmaceuticals. Two dimensional nanomaterials such as tubes and wires have generated considerable interest among the scientific community in recent years. In particular, their novel electrical and mechanical properties are the subject of intense research.

•      Paints.
•   Remediation  (potential of nanoparticles to react with pollutants in soil and groundwater and transform them into harmless compounds).
•    Fuel Cells (potential use of nano-engineered membranes to intensify catalytic processes could enable higher-efficiency, small-scale fuel cells).
•      Displays (next generation of light-emitting phosphors- nanocrystalline zinc selenide, zinc sulphide, cadmium sulphide and lead telluride synthesized by sol–gel techniques).
•      Batteries (Nickel–metal hydride batteries made of nanocrystalline nickel and metal hydrides are envisioned to require less frequent recharging and to last longer because of their large grain boundary /surface  area).
•     Fuel Additives  (addition of nanoparticulate ceria (cerium oxide) to diesel fuel to improve fuel economy by reducing the degradation of fuel consumption over time).
•     Catalysts (uniformity in the size and chemical structure of the catalyst, which in turn leads to greater catalytic activity and the production of fewer byproducts).
•    Research is also being undertaken in many fields such as a) Carbon Nanotube Composites, b) Lubricants,  c) Magnetic Materials, d) Medical Implants,  e) Machinable Ceramics, f) Water Purification, g) Military Battle Suits, h). Drug delivery, i)Vaccines,  j)Biomedical Applications-biosensors, k)stain resistant textiles, l) CNT reinforced tennis rackets and baseball bats, m) Low-cost printing technique for a new generation of complex, flexible sensors.

To conclude I would say, nanotechnology is the major frontier area of science and technology and   if developed into an advanced technology, will be indistinguishable from the magic. Where does the magic come from? magic's in the learning (quoting Dar Williams).. so let us learn, invent and explore “nanotechnology”……..