NanoTechnolgy

Nano means something very small, having a diameter of about 10^-9m. Any technology that can manufacture, design, and talks about synthesis of the devices of such small scale is referred to as nanotechnology, or we can say and the study of the relationship between the material properties and material dimensions of nano scale is known as nanotechnology.  Nanotechnology encompasses the understanding of the fundamental physics, chemistry, biology and technology of nano meter-scale objects.

In order to understand the unusual world of nanotechnology, we need to get an idea of the units of measure involved. A centimeter is one-hundredth of a meter, a millimeter is one-thousandth of a meter, and a micrometer is one-millionth of a meter, but all of these are still huge compared to the nanoscale. A nanometer (nm) is one-billionth of a meter, smaller than the wavelength of visible light and a hundred-thousandth the width of a human hair. This is what you can't imagine so easily.

One of the exciting and challenging aspects of the nanotechnology is the role that quantum mechanics plays in it. The rules of quantum mechanics are very different from classical physics, ­which means that the behavior of substances at the nanoscale can sometimes contradict common sense by behaving erratically. Scientists are experimenting with substances at the nanoscale to learn about their properties. Engineers are trying to use nano-size wires to create smaller, more powerful microprocessors. Doctors are searching for ways to use nano particles in medical applications.

The most immediate challenge in nanotechnology is that we need to learn more about materials and their properties at the nanoscale. Universities and corporations across the world are rigorously studying how atoms fit together to form larger structures. We're still learning about how quantum mechanics impact substances at the nanoscale. Because elements at the nanoscale behave differently than they do in their bulk form, there's a concern that some nanoparticles could be toxic. Some doctors worry that the nanoparticles are so small, that they could easily cross the blood-brain barrier, a membrane that protects the brain from harmful chemicals in the bloodstream.
There are some hefty social concerns about nanotechnology too. Nanotechnology may also allow us to create more powerful weapons, both lethal and non-lethal. Some organizations are concerned that we'll only get around to examining the ethical implications of nanotechnology in weaponry after these devices are built. They urge scientists and politicians to examine carefully all the possibilities of nanotechnology before designing increasingly powerful weapons.

Nano Devices.

The devices of very small diameter of about 10^-9m  are classified as nano devices. Nanotechnology based nano devices such as nano robots, watches, displays have been constructed to perform tests and operations inside the human body, at the places where the machines can't reach, and so on various applications.

Nano devices classification    

• Based on dimensions.
• Based on materials.

Bases on dimensions.

1-D  -   Quantum dots.

2-D  -   Carbon nano tubes and nano wires.

3-D  -    Nano film

4-D  -    Grains.

Based on Materials.

Carbon based materials - Carbon nano tubes and nano wires.

Metal based materials -  MnO, SnO₂  , TiO_2.

Dendrimers.

Applications of Nanotechnology.

1. The development of super computers is a result of nanotechnology , because in the formation of connectors used in super computers we have used nano wires instead of physical connectors.
2. Bacteria tumor cells of gold particles have been developed to destroy most harmful component of cancer cells. It tends to destroy the internal component of cancer without causing any side effect.
   
3. Nanotechnology based clothes have been developed which can absorb the human sweat.
4. TiO₂ is mixed with paints is an example of nanotechnology. As a result the lifetime, strength and shine of the paint is increased.
5. Nanotechnology based machines such as robots, wrist watches have been developed which can predict the diseases in human body in early stages.
   
6. various nano devices have been used for the development of opto-electronic devices.
7. Carbon nano tubes are used for the development of bullet proof jackets.A carbon nanotube is a nano-size cylinder of carbon atoms. Imagine a sheet of carbon atoms, which would look like a sheet of hexagons. If you roll that sheet into a tube, you'd have a carbon nanotube. Carbon nanotube properties depend on how you roll the sheet.     
   
8. Carbon nanotubes can also be effective semiconductors with the right arrangement of atoms. Scientists are still working on finding ways to make carbon nanotubes a realistic option for transistors in microprocessors and other electronics.  
9. Many sunscreens contain nanoparticles of zinc oxide or titanium oxide. Older sunscreen formulas use larger particles, which is what gives most sunscreens their whitish color. Smaller particles are less visible, meaning that when you rub the sunscreen into your skin, it doesn't give you a whitish tinge.
10. Self-cleaning glass - A company called Pilkington offers a product they call Activ Glass, which uses nanoparticles to make the glass photocatalytic and hydrophilic. The photocatalytic effect means that when UV radiation from light hits the glass, nanoparticles become energized and begin to break down and loosen organic molecules on the glass (in other words, dirt). Hydrophilic means that when water makes contact with the glass, it spreads across the glass evenly, which helps wash the glass clean.           
11. Engineers discovered that adding aluminum silicate nanoparticles to scratch-resistant polymer coatings made the coatings more effective, increasing resistance to chipping and scratching. Scratch-resistant coatings are common on everything from cars to eyeglass lenses.
12. Scientist Robert Burrell created a process to manufacture antibacterial bandages using nanoparticles of silver.
13. Nanotechnology may have its biggest impact on the medical industry. Patients will drink fluids containing nanorobots programmed to attack and reconstruct the molecular structure of cancer cells and viruses.
14. Nanotechnology has the potential to have a positive effect on the environment. For instance, scientists could program airborne nanorobots to rebuild the thinning ozone layer. Nanorobots could remove contaminants from water sources and clean up oil spills.