Nanotechnology is the branch of technology in which manipulation of nano (tiny) materials at atomic or molecular scale is done due to which its properties differ significantly from those at a larger scale. In the past the phenomena was already put to use in the field of cosmetics and sunscreen. But now the new technology will be utilised enormously in the fields of healthcare, filtration, infrastructure, electronics, power etc.
The first time the idea of nanotechnology(NT) was introduced in 1959, when Richard Feynman, a physicist at Caltech, gave a talk titled “There is plenty of room at the bottom” and then Drexler’s vision of molecular manufacturing has evolved the field in the 21st century to largely include research in chemistry, materials science and molecular engineering.
Prof CNR Rao pioneered and fostered nanoscience research in India. Our former President APJ Abdul Kalam at his inaugural speech for Indo-US NT conclave on February 22, 2006 praised the Indian scientists for their NT work.
In the new technology, all the materials are measured in the scale of nano-metres (nm) and the particles of size between 1 to 100 nm are considered as nano-materials. 1 nm = 10 -9 metres and 1000 nm = 1 micrometre. The approximate sizes of certain nano-objects with which we are familiar are: red blood cell (7000nm), white blood cell (10000nm), water molecule (0.3nm), protein (5-50nm), DNA (2nm), Hydrogen atom (0.1nm), human hair width (80000 nm), virus (75-100nm), and bacteria (1000-10000nm).
The materials at nano-size have its properties changed in reactivity, strength, stiffness and also for optical, electrical and magnetic behavior because of two main reasons: increased surface area to volume ratio and quantum effects. These changes in the properties at nano-scale provide challenging usage in the various fields.
It is interesting to note what certain-changes take place at nano- stage: Copper is opaque but becomes transparent at nano-scale; stable aluminum becomes combustible; solid gold changes to liquid gold at room temperature; inert gold becomes catalyst; insulator silicon becomes conductor.
The displays for the various shaped nano-objects that are possible on the computer can be accomplished by the use of very powerful electron microscope.
Research has shown that carbon nano tubes CNTs have multiple applications in the fields of nano-electronics and power systems. It is hoped that such materials would open the space frontier by radically lowering the cost of launch to orbit.
The NT is beneficially used in the following fields:
Healthcare
Nano-scale devices can readily interact with bio-molecules on the surface and inside of cells and offers new and innovative ways to diagnose and treat cancer in the ways unimagined before now.
The so called ‘Tissue Engineering’ makes use of artificially stimulated cell proliferation by using suitable nano-material-based scaffolds and growth factors for the regeneration or replacement of body parts that may be lost due to disease or accident..
One of the exciting applications is the possibility of heart pace-maker like device. Nanotube will be seated in the human body and the power will be provided by the circulation of the blood.
NT is being used as drug delivery system developed by the Indian scientists. The overall drug consumption and side-effects can be lowered significantly by depositing the active agent in the morbid region only.
Indians have recently designed nano-condoms to be coated with a gell-based formulation of a nano pharmaceutical that will be used to prevent and treat Sexually Transmitted Diseases.
Fruits like papaya, guava, and vegetables like tomatoes are natural sources of antioxidants. If normal antioxidants fall short in case of poor diet, US researcher’s design of a nano-sized “Trojan horse” particle can ensure better absorption of antioxidants by the body.
Tiny narrow-wire sensors that are less than the width of human hair are 1000 times more sensitive than conventional DNA test and they are capable of producing results in minutes rather than days. This paves the way of faster, more accurate medical diagnosis test for countless conditions.
Ultra-filtration
The scientists from Banaras Hindu University have devised simple and efficient ultra-filters to remove micro to nano scale contaminants from water and heavy hydrocarbons from petroleum.
Infrastructure
Nano science and material research would be of great use with bioactive coatings on civil works such as buildings, roads, bridges and industrial units that could be made resistant to ultraviolet and infrared radiation; with the research seepage of water that is likely at plumbing installations, through the wall and roof during heavy rains also can be avoided.
It has the potential to make civil construction faster, cheaper, safer and with more varied automation for the advanced modern homes and massive skyscrapers.
Electronic equipments
In the modern communication technology traditional analog electrical devices are increasingly replaced by optical or optoelectronic devices.
Molecular switches and circuits along with nano-scale will pave the way for the next generation of computers. Ultra dense computer will result in low power, low cost, nano size and yet with faster assemblies.
We may have Quantum Computer in the near future that could harness the power of atoms and molecules to perform memory and processing tasks significantly faster than any silicon-based computer. It would work on qubits (atoms, ions, photons, or electrons).
Power
Today’s ordinary solar cells have about 20 per cent efficiency of using Sun’s energy. NT could help increase the efficiency of light conversion by using nanostructure with continuum of bandgaps.
Currently used bubs convert approximately 5 per cent of electrical energy into light. With NT approach, light emitting diodes or quantum caged atoms could lead to a strong reduction of energy consumption for illumination.
Miscellaneous uses
Sunscreen based on mineral nano-particles of titanium dioxide has long-term stability, UV protection and reduction in undesirable whitening.
The sunglasses using protective and anti-reflective ultra-thin polymer coatings are on the market. NT also offers scratch resistant surface coatings for optical sector.
Self cleaning and UV radiation resistant glass surface with NT is now possible. In the field of cosmetics, such novel products have promising potential.
A Swiss scientist discovered in 2008 that NT structure allows the surface to be covered in chemicals that make the clothing hydrophobic; water simply bounces or sides off. The technology can also repel dirt and sweat. With the use of NT the modern textiles will be wrinkle resistant and stain repellent.
Lighter and stronger nano-materials will be of immense use to aircraft manufacturers, leading to increased performance.
The potential of nano-particles to react with pollutants in soil and ground water to be transformed into harmless compounds is being researched.
A nano-composite coating process could improve food packaging by placing anti-microbial agents.
Traditional polymer can be reinforced by nano-particles results in a novel material that can be used as light weight replacement for metal.
With small grains, interface area greatly increases which enhances the strength. Nano-crystalline nickel is as strong as hardened steel.
It is also claimed that the nano-particles reduce friction between metal surfaces particularly at high normal loads.
Futuristic use of nano-coating on the swimming pool walls by photo-catalytically active material can lead to activation of oxygen forming anti-bacterial compounds.
Thus some of the applications and uses described above indicate how powerful Nanotechnology is; it has lot of potential for the further growth too.
(The writer is a former ‘Project Management Consultant’ for local and abroad civil construction activities. He can be contacted at 11, Sameepan, Bamanwada, Sahar, Vile Parle (E), Mumbai 400099; e-mail: a_railkar@rediffmail.com)
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