Maharashtra Board Class 12 Chemistry Chapter 16 Green Chemistry And Nanochemistry PDF Download

History of Nanotechnology

Nanomaterials have been produced and used by humans for hundreds of years. However, understanding of certain materials as nanostructured materials is relatively recent. Due to the development of advanced tools that is sophisticated instruments, it has been possible to reveal the information at nanoscale.

Beautiful ruby red colour of some ancient glass paintings is due to gold and silver nanoparticles trapped in the glass matrix.

The decorative glaze or metallic film known as lustre found on some medieval pottery is due to certain spherical metallic nanoparticles.

Carbon black is a nanostructured material that is used in tyres of car to increase the life of tyre. (Discovery in 1900). Carbon nanotubes are made up of graphite sheets with nanosized diameter. They have highest strength.

Fumed silica, a component of silicon rubber, coatings, sealants and adhesives is also a nanostructured material.

Teacher's Note

Nanotechnology is very old. It was used in ancient times without knowing what it was. For example, red color in old glass paintings came from tiny gold particles.

Exam Trick

Remember: Ancient people used nano materials without knowing the science. Nano = very very small. Like a grain of rice is big compared to nano particles!

Points to Remember

Nanomaterials were used by humans for hundreds of years ago.
Ancient glass had gold and silver nanoparticles in it.
Medieval pottery had metallic nanoparticles.
Carbon black in car tires is a nanostructured material.
Fumed silica is used in rubber and coatings.

Do You Know?

The term 'nanotechnology' was defined by Tokyo science University Professor, Nario Taniguchi in 1974.

Invention of Scanning Tunneling Microscope (STM) in 1980, led to the discovery of fullerenes in 1986 and carbon nanotubes a few years later.

Teacher's Note

The word 'nanotechnology' is only about 50 years old. But people used nano materials thousands of years ago in India and all over the world.

Exam Trick

Remember the year 1974 when nanotechnology got its name. And STM was invented in 1980. These dates are important for exams.

Points to Remember

Nario Taniguchi defined the word 'nanotechnology' in 1974.
STM was invented in 1980.
Fullerenes were discovered in 1986.
Carbon nanotubes were discovered a few years after 1986.

Applications of Nanomaterials

Nanochemistry has already contributed to number of innovative products in various disciplines because of their unique physical, chemical, optical, structural, catalytic properties and so on. Few applications are given below:

Nanoparticles can contribute to stronger, lighter, cleaner and smarter surfaces and systems. They are used in the manufacturing of scratchproof eyeglasses, transport, sunscreen, crack resistant paints and so on.

Used in electronic devices. For example, Magnetoresistive Random Acess memory (MRAM).

Nanotechnology plays an important role in water purification techniques. Water contains waterborne pathogens like viruses, bacteria. 1.1 billion people are without access to an improved water supply. The provision of safe drinking water is currently high priority. Recently, cost effective filter materials coated with silver nanoparticles (AgNps) is an alternative technology. For example: water purifier. Silver nanoparticles act as highly effective bacterial disinfectant, remove E.Coli from water.

Self cleaning materials: Lotus is an example of self cleaning. The lotus plant (Nelumbo nucifera) although grows in muddy water, its leaves always appear clean. The plants' leaves are superhydrophobic. Nanostructures on lotus leaves repel water which carries dirt as it rolls off. Lotus effect is the basis of self cleaning windows.

Teacher's Note

Nanoparticles are used in many things we see every day in India. Water purifiers in our homes use silver nanoparticles. Sunscreen lotions have nano particles to protect our skin.

Exam Trick

Remember: Lotus leaf is self-cleaning. This is called "Lotus Effect". Silver nanoparticles kill bacteria in water. These are big exam topics!

Points to Remember

Nanoparticles make eyeglasses scratchproof.
Nanoparticles are used in electronic devices like computer memory.
Silver nanoparticles clean water and kill bacteria.
Lotus leaf is naturally self-cleaning because of nano structures.
Water purifiers use nano technology to remove germs.

Nanoparticles and Nanotechnology

Advantages

Revolution in electronics and computing.

Energy sector - nanotechnology will make solar power more economical. Energy storage devices will become more efficient.

Medical field: Manufacturing of smart drugs, helps cure faster and without side effects. Curing of life threatening diseases like cancer and diabetes.

Disadvantages

Despite the possibilities and the advancements that the nanotechnology offers to the world, there also exist certain potential risks involved with the disadvantages of it.

Nanotechnology has raised the standard of living but at the same time, it has increased the pollution which includes air pollution. The pollution caused by nanotechnology is known as nano pollution. This kind of pollution is very dangerous for living organisms.

Nanoparticles can cause lung damage. Inhaled particulated matter can be deposited throughout the human respiratory tract and then deposit in lungs.

The characteristics of nanoparticles that are relevant for health effects are size, chemical composition and shape.

Teacher's Note

Nanotechnology is very good but it can also harm us. Nano particles are so small that they can enter our lungs and cause problems. We must use it carefully in India.

Exam Trick

Remember: Nanotechnology has good things (medicines, clean water) and bad things (nano pollution, lung damage). Write both advantages and disadvantages in exam.

Points to Remember

Nanotechnology helps make computers faster and better.
Nanotechnology can help cure cancer and diabetes.
Solar power will be cheaper because of nanotechnology.
Nano pollution is very dangerous for all living things.
Nano particles can damage our lungs if we breathe them.

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