Prof. Vila sShamrao patil

1. 1.5.Applications of Nanoparticles Nanomaterials
At nanoscale the materials change their physical
properties such as colour, resistance, strength etc.
drammatically. These special properties can be used in
many fields for making new devices, instruments and
consumer goods. These nanoscale devices are extremely
small in dimensions and have unique features. Some of the
applications are as mentioned below.
Because of unique physical, chemical and mechanical
properties, nanomaterials have wide range of applications.
Some of the applications are described here.
1.Electronics-
The discovery of semiconductor transistor replaced the
heavy and power consuming vacuum tubes. The transistors
are power saving, small and light weight. The Integrated
Circuits (ICs) made the instruments still smaller by
fabricating a number of large components on a small chip.
But the size of components cannot be reduced to atomic
level, because after some level the properties of materials
become size dependent. At this level, the 'nanoscience' or
'nanotechnology' comes into the picture.
Single Electron Transistor (SET). Spin Valves and
Magnetic Tunnel Junctions (MTJ) are the new devices based

2. on nanotechnology. These devices are small, faster and
relatively cheaper. The spin valve type devices are used in
personal computers to read disk, which have enabled to
increase data storage capacity of hard disks. These are the
devices based on charge and spin. Earlier, devices were
based on charge only and spin was neglected. The spin-
based electronics is called as 'spintronie or
'magnetoelectronics'. Using an external magnetic field, spin
transport can be controlled. The advantage with spin is that
it cannot be easily destroyed by scattering from collisions
with other charges, impurities or imperfectioni. Some of
the spin-based devices are Spin FET, Spin LED, Spin, RTD etc.
Nanotechnology can also be used in computers for
designing 'nonvolatile memory', smaller and faster
microprocessor and better quality monitors. The
nanoparticle coating on screen of TV or monitors will
improve quality' and resolution.
2.Energy-
Currently used energy sources are firewood, coal, oil
and gas. These sources are limited in nature and large-scale
use of these sources is damaging environment. So scientists
have started searching some alternatives which will solve

3. problems with conventional sources of energies. Some of
the non-conventional sources of energies are solar energy,
hydel energy, tidal energy, biomass energy etc. The
disadvantage of solar cells is that their efficiency is less (—
30%) and hence require large surface area. Research is
going on to use nanomaterials for making solar cells, which
will reduce the size of the cells and increase the efficiency.
Other source of energy is hydrogen fuel, which can be
obtained by splitting water (H20) using sunlight in presence
of nanomaterials. The nanomaterial will work as
'photocatalyst'. The main problem with hydrogen is storage
as it can catch fire easily. Materials like carbon nanotubes
can be used as storage material without risk. Portable
electronic appliances such as mobile phones, laptops,
calculators etc. require rechargeable, light-weight
batteries. Such batteries require frequent replacement or
recharging as their energy density is low. Attempts are
being made to increase their energy density by replacing
the electrode materials.
3.Automobiles:-
The body of a car is made up of steel and some alloys.
The body structure should be strong and non-deformable.
The nanotube composites have mechanical strength better

4. than steel and attempts are made to make composites that
can replace steel. Currently, manufacturing of nanotubes is
expensive but scientists are trying to make it economical.
Nanoparticle paints provide smooth, thin and
attractive coating. Research is going on to change the
colour of car by applying a small voltage. Self-cleaning glass
can be made by mixing small amount of titania (Ti02)
nanoparticles while manufacturing it. The titania is capable
of dissociating organic dust in presence of UV light present
in sunlight. Once dissociated, it may fall down or evaporate.
Water droplets on glass give hazy look, but titania glass can
spread the water evenly giving clear sight. Such special glass
can be used to make window glass of a car. By using
nanoparticles light weight and less rubber consuming,
thinner tyres can be made. This will reduce the weight,
price of the car and will increase the mileage as a result of
reduced weight Nanoparticles can be used as catalysts to
convert harmful emissions into less harmful gases. With the
help of nanocarbon tubes, hydrogen fuel can be stored
safely and can be used for running a car. The hydrogen fuel
is eco-friendly and ever lasting.
4 Space and Defence

5. In space and defence also, scientists are trying to
replace the conventional materials by nanomaterials. A
nanoporous material called 'aerogels' have extremely low
density ranging between 0.01 to 0.8 gm/cm3. Aerogels
have small nanosized pores in them and can be of various
materials. Basically, aerogels are poor conductors of heat.
Therefore, aerogels can be used in spacecrafts to reduce
the weight. Even special light-weight suits and jackets can
be made using aerogels. In satellites or spacecrafts, we use
solar energy. But solar cells have low efficiency resulting in
large surface area and heavy weight. Nanoparticles can be
used to reduce the size and weight of solar cells. Space
vehicles also need materials which can withstand harsh and
extreme conditions during launching and in space. Polymer
composites using silica fibres and nanoparticles have larger
Young's modulus, low temperature coefficient of expansion
and high impact strength. The nanoparticles in polymer
composites are better radiation protectors in comparison
to microparticle-based composites.
5. Medical
The nanoparticles can be used for drug delivery,
detection of cancer or tumor and treating them. As
nanoparticles are very small in size, they can be injected

6. easily and can be guided towards specific part in the body.
Recently, gold nanorods which have strong scattering and
absorption property in the infrared are used to detect and
destroy cancer cells in rats. The infrared laser beam can be
used to detect and destroy cancer cells without affecting
the healthy cells. This is possible because healthy cells
require twice the laser power as compared to cancer cell
for destruction and infrared light can get easily transmitted
through cells and muscles. Thus, by using low power
infrared laser, only cancer cells can be killed without
affecting the healthy cells
Drugs can be encapsulated in nanocapsules and can be
guided towards desired part of the body. Then drug can be
delivered in controlled manner, fastly and slowly, by
opening the capsule in desired way. The opening of capsule
can be controlled externally by magnetic field, infrared light
or physiologically. This will help in treating diabetic or HIV
affected patients. The scientists are also working to develop
better body implants. The body implants should be strong
and biocompatible. The body implant should be strong
enough so_that it does not get deformed easily. Also, it
should be biocompatible so that once implanted body cells
should be able to grow. Some nanotechnology-based tests

7. are developed which are'simple and fast. These tests can be
used for detection of viruses, DNA, proteins and antibodies.
Porous silicon and carbon nanotubes-based sensors can
also be used in medical field.
6. Environmental
Whenever a new technology emerges, there is always
concern about its impact on social life, health and
environment. Technology brings comfort in life but it also
creates problems such as global climatic changes, pollution,
new deceases, depletion of natural resources etc.
Therefore, the question arises whether the
nanotechnology will solve or increase these problems.
Although ill effects of nanoparticles are possible but they
are not studied yet. On the other hand, it is believed that
nanomaterials themselves will reduce the pollution and
environment related problems. Efficient production of
nanomaterial by low temperature synthesis routes will help
to reduce industrial pollution. Use of nanomaterials as
hydrogen fuel storage and oil filters may reduce emission
by vehicles. The nanomaterials are light weight and require
only small quantity. This will bring down the prices of
products making them affordable. Thus likely to solve
problems of poor people. The nanoparticle-based sensors

8. are much sensitive than conventional sensors being used.
These nanoparticle-based sensors will be capable to detect
and rectify problems. Such sensors will be useful in water
purification systems, detection of toxic ions, metal ions,
pesticides etc. and their remediation on large scale.
Environment - Better insultation material: Aerogels are
porous and extremely light weight.and used for insulation
in offices and homes. Aerogels do not emit chloro flutro
carbon (CFC) like other insulating materials. Also aerogels
are used in smart windows.
Elimination of Pollutants: Being highly reactive,
nanomaterials can be used as catalyst to react with toxic
gases like carbon monoxide, nitrogen oxide and reduce
pollution.
Energy: Nanomaterials including carbon nano tubes,
thin films, quantum dots are cost effective and enhance the
performance of solar panels.
7.Textile
The special threads and dyes used in textile industry
are products of nanotechnology. Clothes produced with
such technology will give pleasant look of synthetic fiber
but comfort of cotton. These clothes will not require ironing

9. or frequent cleaning. Some of the washing machine
companies are trying to use silver nanoparticles in washing
machines which will make the clothes germ-free.
8.Cosmetics
Nanoparticles are widely used in cosmetic industry.
Due to their small size nanoparticle-based creams are
better option as they can be used in small amount and do
not lease any gaps between them. This gives a smooth
appearance. Zinc oxide and titanium oxide nanoparticles of
uniform size are able to absorb ultraviolet light and protect
the skin from ultraviolet radiations. The small nanoparticles
in some of the creams scatter light in such a way that the
appearance of wrinkles is suppressed. Nanoparticle-based
dyes and colours are harmless to skin and can be used in
hair creams or gels. Some creams using nanoparticles are
already in market and becoming quite popular.
9. Electrochromic display –
In electrochromic devices, there is change in optical
properties of material when electric field is applied.
Nanocrystalline materials like tungstic oxide are used in
electrochromic displays. It displays information by changing
colour when voltage is applied.
10) Self cleaning glass - -

10. The glasses coated with nanoparticals becomes
photocatalytic and hydrophilic. When UV rays are incident
on glass, nanoparticals become energized and begin to
breakdown organicparticals on the surface. Due to
hydrophilic nature, glass attracts water droplets and cleans
it.
11) Scratch resistant coating –
Glass coated with thin film of hard nanomaterial
becomes scratch resistant.
12) Sunscreen -Nanoparticles of zinc oxide or titanium
oxide are used in sunscreen.
13) clothing -Fabric is coated with zinc oxide nanoparticles
gives protection against UV rays. Silver nanoparticles have
antibacterial effect on clothes.
14) Harder cutting tools - Cutting tools made of
nanocrystalline materials like tungsten carbide, titanium
carbide are harder, ware resistant and long lasting.
15) Ductile, machinable ceramics -Ceramics are hard and
brittle in nature. But nanosized zirconia becomes super
plastic i.e. it can be deformed to great length.
Nanocrystalline ceramics like silicon nitride are used in ld
strength spring, ball bearing, valve lifter etc.

11. 16) High sensitivity sensor-There is change in electrical,
chemical, thermal, magnetic properties of Material at
nanoscale. It is used in making high sensitivity sensors.
17) Molecular Electronics - STM is utilized in development
of molecular electronics. Molecular diodes and transistors
lead to miniaturization of integrated circuits. Nanodevices
exhibit low power, high packaging density and high speed.
18) Computer memory -Using STM, scientists have created
an atomic scale memory using atoms of silicon. Atom
represents one and the gap between atoms represents
zero. Its storage capacity is million-times greater than
conventional CD-ROM.
19) Medical applications - Nanotechnology provides a
new tool to read the genetic code. It can help to detect
cancer at early stage. Nanobots (nanoscale robots) can be
inserted into bodies for imaging, diagnosis and drug
delivery.