Introduction Of Nanotechnology

Niket PowarJunior Research Fellow.

Definition : “The branch of technology that deals with dimensions of less than 100 nanometres, especially the manipulation of

individual atoms and molecules.”

Or"Nano-technology” mainly consists of the processing of

separation, consolidation, and deformation of materials by one atom or one molecule.

By Norio Taniguchi

History Of Nanotechnology The first ever concept was presented in 1959 by the famous

professor of Dr. Richard Feynman in the lecture of “There’s plenty of rooms at the bottom”

and The Nobel prize was awarded in 1965.

Dr. Richard Feynman

The term “Nano technology” had been coined by Norio Taniguchi in

1974. Gives the idea of “Molecular Machinery Manufacturing and Computation” in 1980’s.

Prof. Norio Taniguchi Dr. Eric Drexler

Some Ancient Nano Material 1000 year’s ago different size “Gold Nanoparticles”

are used for produces stained glass windows.

2000 year’s ago “Sulphide Nano crystals” used by the Greek and Roman for dye of the hair.

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Lycurgus Cup(Roman 4th Century) The glass contains gold-silver alloyed nanoparticles,

which are distributed in such a way to make the glass look green in reflected light but,

when light passes through the cup, it reveals a brilliant red.

Nanometer Scale

Nature And Nanotechnology

The colours of beetle and butterfly wings come from the scattering of light.

Light hits the nanostructures on their scales. These nanostructures are typically smaller

than the wavelengths of visible light (smaller than 400 nanometres).

These nanostructures don’t just make me pretty. They also keep me clean by shedding water and dirt!

How sticky? As sticky as a …Gecko?

“On the sole of a gecko’s toes there are some one billion tiny adhesive hairs,

about 200 nanometres in both width and length. The shape of the fibres is also significant;

for example, spatula-shaped ends on the hairs provide particularly strong adhesion.” 

Colour Can Be Iridescent, Too!Thin films are made of nanoparticles,

smaller than 400 nanometers, that produce iridescent (rainbow-like) colors

when light strikes them.

Iridescent colors change when you look at the object from different angles.

Approach Of Nanotechnology

Top Down Method Bottom Up Method

Top Down Method

Some of the following method of top down method :

Photolithography : Photolithography uses light (UV, deep-UV, extreme-UV or X-ray) to expose a layer of radiation-sensitive through mask polymer(photoresist)

Photolithography : Photolithography uses light to expose a layer of

radiation-sensitive through mask polymer(photoresist)

Scanning lithography : Energetic particles such as electrons and ions can be used to pattern appropriate resist films leading to features with nanometre resolution. recently established technology uses nanometre scanning probes for patterning resistfilms and is therefore referred to as Scanning Probe Lithography (SPL).

E-beam lithography :Electron beam lithography or Electron-Beam Direct-Write Lithography scans a focused beam of electrons on a surface covered with an electron-sensitive film or resist to draw custom shapes. By changing the solubility of the resist and subsequent selective removal of material by immersion in a solvent, sub-10 nm resolutions have been achieved.

Bottom Up method

some of the following method for preparation of nanoparticle.

Chemical vapour deposition :Precursor gases are delivered into the reaction chamber at approximately ambient temperatures. As they pass over or come into contact with a heated substrate, they react or decompose forming a solid phase which and are deposited onto the substrate. The substrate temperature is critical and can influence what reactions will take place.

Sol-Gel Method :

Why Bottom Up• Allows smaller geometries than photolithography. • Certain structures such as Carbon Nanotubes and

Si nanowires are grown through a bottom-up process.

• New technologies such as organic semiconductors employ bottom-up processes to pattern them.

• Can make formation of films and structures much easier.

• Is more economical than top-down in that it does not waste material to etching

Surface Area to Volume Ratio In nanomaterial the surface /boundary / interface plays importance role.As surface area per mass of material increase greater amount of the material can comes contact with surrounding material thus affect the reactivity.

Classification Of Nanomaterial Zero Dimensional :

These nanoparticles are spherical in size and the diameter of these particles will be in the1-50 nm range.

One Dimensional : These materials are long (several micrometre in length)

but with diameter of only a few nanometre.

Gold Nano particle

Carbon Nanotube

Two Dimensional :

These include different kind of Nano films such as coatings and thin-film-multilayers,

Nano sheets or Nano-walls. The area of the Nano films can be

large (several square micrometre),but the thickness is always in Nano scale range

Three Dimensional : These include bulk materials composed of

the individual blocks which are in the nanometre scale (1-100 nm).

Solar thin film

Bulk Material

Carbon Based NanotubesTypes Of Carbon Nanotubes :

Single Walled Nanotube (SWNT) :

Multi Walled Nanotube(MWNT) :

Properties Of Nanotubes Tensile & Compressive Strength :

The tensile strength of” carbon nanotubes is approximately 100 times greater than

that of steel of the same diameter”.

Hardness : SWNT nanotube hardness about 25× 109 Pa.

It is higher than Diamond and Prepared under high pressure and temperature.

Nanotube is super hard phase and they have bulk modulus of 465-546 GPa (1GPa=10 9)

Spinning Nanotube fibre

Electrical Properties : metallic nanotubes can carry an electric current

density of 4 × 109 A/cm2, which is more than 1,000 times greater

than those of metals such as copper, where for copper interconnects

current densities are limited by electro migration.It is act as Superconductivity up to 12 K.

Thermal Properties : SWNT has thermal conductivity 3500 W/ m.K

while Copper has 385 W/m.Thermal stability in vacuum up to 3100 K and 1000 K in air.

Application Of Nanotechnology Energy Source :

Microbial Fuel Cell :

Microbial fuel cell is a device in which bacteria

consume water-soluble waste such assugar, starch and alcohols and

produces electricity plus clean water.

C12H22O11 + 13H2O ---> 12CO2 + 48H+ + 48e-

Cathode Reaction: 4H+ + O2 + 4e- 2H2O

Carbon nanotubes - Microbial fuel cell

Anode Reaction:

Hydrogen Fuel cell :

A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction of positively charged hydrogen ions with oxygen or another oxidizing agent.

Hydrogen fuel cells power the shuttle's electrical systems, producing a clean by-product - pure water, which the crew drinks. A fuel cell combines hydrogen and oxygen to produce electricity, heat, and water.

Health Sector :

Nano Robotics :

He first useful applications of Nano machines may be in Nano medicine.

For example, biological machines could be used to identify and destroy cancer cells.

Another potential application is the detection of toxic chemicals, and the measurement

of their concentrations, in the environment

Nano Sponges :The development of new colloidal carrier called

Nano sponges has the potential to solve these problems. Nanosponage is a novel and

emerging technology it can precisely control the release rates of controlled drug delivery for topical use. 

ADVANTAGES OF NANOSPONGES  Targeted site specific drug delivery.

This Technology offers entrapment of wide variety of ingredients and reduced side effects.

Improved Stability, increased elegance and enhanced formulation flexibility.

Security: Bullet Proof Clothing :

"When a bullet strikes body armour, the fibres of these materials absorb and disperse the impact energy to successive layers to prevent the bullet from penetrating" 

a) Initial model, (b) a deformed nanotube at its maximum energy absorption.

Electro chromic Camouflage :

Scientists are manipulating light so soldiers seem to disappear.

Scientists are also working on "electro chromic camouflage" – fabric which changes colours instantly to blend in with the surroundings.

Nano paint currently developing by scientist to makeInvisible of missile, aircraft so it is difficult to detect.

Nano Sensor : Blue Crab Nano sensors :

What is Chitosan?A biological compound that readily binds

to negatively charged surfaces

It can interact with a wide variety of substances and

works well in complex, sensitive devices, such as Nano sensors

A substance found in the shell, called chitosan, is a key component used in a Nano sensor, a “system on a chip” at the Nano scale

developed at the “University of Maryland”

Detects minute quantities of explosives, bio agents, chemicals, and other dangerous materials in air and water

This could lead to security and safety developments for airports, hospitals, etc.

Bio sensor :

Chemical Sensor: • Incorporates capacitive readout cantilevers and electronics

for signal analysis• sensitive enough to detect single chemical and biological

molecules.

Aerospace: Nano sensors can pass through membranes and into white blood cells, called lymphocytes, to detect early radiation damage or infection in astronauts.

•DNA molecules attach to the ends of vertical carbon nanotubes that are grown on a silicon chip

•These detect specific types of DNA in an analyze.

Future Challenges In Nano technology

Reducing the cost of materials and devices.

Improving reliability

Implication of nanotechnology on society.

Environmental problem can solve.

Innovation of Nano drugs which will be less side effect and more effective.

Disadvantages• The engineered robots will perform jobs instead

of people which will result in a loss of jobs.

• The wastes released while making the materials for nanotechnology are released into the atmosphere and can even penetrate human and animal cells and effect their performance.

• Agricultural countries will lose their income as nanotechnology will take over.

• It has very high initial investment costs along with high manufacturing costs.

• If any damage is done at the molecular level then it is not possible to revert it.

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