History of Nanotechnology and Chemistry of Colours .......

1. -NANOTECHNOLOGY-
CHEMISTRY OF COLOURS
Dr. Radhika T.
June 2020

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Cool Colours of TATA nano…
Era- that of nano…. March 2009.
Inexpensive, City car, 4 passengers…
Rs 1,00000 only!!!!!!

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Apple iPod, Pink butterfly skin….fantasy..
6 th Generation….
Smaller and Lighter..

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Nano- Milestone
• 1959 , Richard Feynman Delivers “ Plenty of Room
at the Bottom”:- Father of Nanotechnology….
Nobel prize, Physics (1965)
What is a “nano”?
 A nano is one billionth of a meter or 10-9 m
1-100 nanometer range

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…..manipulating matter on an atomic and molecular scale.
….deals with structures sized between 1 and 100 nanometer.
Nanotechnology – New Chemistry
Definition by Norio Taniguchi, Japan, 1974.
One nanometer (nm) is one billionth, or 10−9, of a meter.
Requires expertise in physics, chemistry, material science,
biology, mechanical and electrical engineering.
Nano in Greek means “dwarf” but is infinitely smaller than a dwarf…
Control in the atomic level….Fiction???

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Individual atoms
< 1 nm.
DNA
> 2.5 nm.
Increasing size
Millions of atoms
3 atoms
Buckminster
Fullerene
~1.1 nm
1-100 nm : Nanostructures…
smallest things that can made…..

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Human
2000 000 000 nm.

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Total Surface Area Increases while Total Volume Stays Constant
 Smaller – Larger surface area compared to volume.
 High surface-to-volume ratio - nanoparticles.
Melon cube with sugar

9. Nanotechnology?
 Science :- atoms and molecules make new materials and devices.
 Nanoscience – learn about the chemical and physical properties of
materials at the 1- 100 nanometer (nm) scale.
 Nanotechnology – develop and apply materials at this scale to develop
new products or methods; i.e., turning nanostructures into useable
tools and applications

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Nanoscience

11. Unique Properties……
 Properties of materials behave differently and are said to behave under
atomic and molecular rules.
 Researchers are using these unique properties of materials at this small
scale to create new and exciting tools and products in all areas of
science and engineering.

12. Nanofabrication
 Top-down – start with large material and bring it
down to the nanoscale
 Bottom-up – start with individual atoms and build
upwards to make a nanostructure

13. Nanotechnology - History
 Ancient stained-glass makers used nanosized gold and silver particles.
 Gold nanoparticles in glass are reflected as red..
Optical properties change with the nanoscale….

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Art- Glass at Chartres
Cathedral
Lycurgus cup green- when light shines on it…
Red when light shines inside…
Gold & Ag nanoparticles….

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Charm of nanotechnology…..
Peacock feather…..
 Nature won
nanoparticles play
making vivid colours…

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Base of gecko’s feet: Superglue
Insect with nano wing structure..
(Hexagonal lattice )
Animals- Nanolife

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Nanotopography of the wing’s surface…..
Many tiny (nano) scales and veins…….

18. Nanoscience Biomimicry
Ways scientists are attempting to mimic the wonders of
nanoscience in nature:
•sticky “feet”
•strong spider silk
•water collecting beetle backs
•self-cleaning light reflecting butterfly wings
•optical nanoscience
•and the list could go on and on.
•tough and light toucan beaks
Taken from WebQuest Nanoscience in Nature by Jeanne Nye

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Nature Nano….
 Materials reduced to the nanoscale can show different properties
compared to what they exhibit on a macroscale, enabling unique
applications…..
Why green plant green?
Light sensitive pigments- molecules with nano dimensions
Absorb light (photon) and direct to the photosynthesis centers.

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Technology:- Self cleaning paints, supplies and roofs…
Nano Lotus….
Water drops on lotus leaf…
Nanodimensions, hydrophobic…
Lotus Effect…..
Micro-nano roughness of the surface…
….self-cleaning properties as a result of
very high water repellence …..

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Particles in a colloid scatter the beams of light
When a beam of light passes through a colloid, the colloidal particles
present in the solution do not allow the beam to completely pass through.
The light collides with the colloidal particles and is scattered (it deviates
from its normal trajectory, which is a straight line).
Scattering makes the path of the light beam visible………
….diameters of the particles , 40 to 900 nanometers (1 nanometer = 10-9 meter).
Wavelength of visible light ranges from 400 to 750 nanometer…..
Tyndall effect
Irish physicist John Tyndall

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 Milk is a colloid that contains globules of fat and protein. When a beam of
light is directed at a glass of milk, the light is scattered.
 When a torch is switched on in a foggy environment, the path of the light
becomes visible. Water droplets in the fog are responsible for the light
scattering.
 Opalescent glass has a bluish appearance when viewed from the side.
However, orange-colored light emerges when light is shined through the
glass.

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Beautiful colours depends on material, mixing, coating etc….
Nano in Cosmetics
Facial cream…
Nanosilver cosmetics…

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NanoFood
Can make healthy donuts….
Nano designed fruit….
Fruits with only useful
contents..

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Nano fireworks….
April 2009:-
Bigger and better fireworks…..thanks to the use of nanotechnology to
create compounds that burn faster and more efficiently.
US researchers created the flammable material by combining
nanoparticles of a copper oxide oxidiser with a polymer organic fuel.

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Nano in Medicine…..

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Hottest new areas….
Drug delivery
Nanorobots..

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• Can assist with the detection of disease
in very small cell or tissue samples.
• Less invasive examination of living cells
within the body.
Biological Nanodevices…..

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 Transistors from carbon nanotubes
 Integrated chips from these transistors..
 Graphene films
 Gold nanoparticles- organic molecules 29
iPOD nano; digital audio player designed and marketed by Apple..
Portable, light weight..
Japan Scientists –more no of chips….high price.
6 generation.
Reduce weight from 49 g to 21.1 g
Nanoelectronics at present..

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Mimic the vivid iridescent colours of tropical butterflies,
Created by light bouncing off microscopic wing structures
 Bank notes could one day be made as beautiful as butterfly wings using
technology borrowed from nature.
 Passports, credit cards etc…
Biotemplated Nanotechnology Materails
recreates the wing of butterflies…… May 2010.
Butterfly wing under microscope…

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Photonic crystals- Insertion of ZnO in peacock feather to
create variety of colours….
Tuning photonic crystals for various applications…
August 2010..
Ideas inspire design and synthesis of future nanocomposites photo crystals..

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Magic of Gold nanomaterials…..
White gold
Red and White gold
Gold coated car…

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Colour chemistry- Band Theory
When very large numbers of atoms (metals) brought close to each other, low and high
energy bands overlap.
Electrons move freely in this continuous band of available energy levels….
When light strikes the surface of a
metal, electrons in a lower energy
excited to a higher energy level.
As the number of neighboring atoms
increases, spacing between the energy
levels decreases.
More overlap occurs and it replace
the distinct energy levels.
As more atoms combine, the distance
between the 2 bands decreases, the
band gap decreases, and less energy is
required for electron excitation.

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Above Fermi level, energy levels
are empty (at absolute zero), and
can accept excited electrons.
Surface of a metal can absorb all
wavelengths of incident light.
Excited electrons jump to a
higher unoccupied energy level.
Created current rapidly
discharges to emit a photon of
light of same wavelength.
Most of the incident light is
immediately re-emitted at the
surface, creating the metallic
luster we see in gold, silver,
copper, and other metals.
 Most metals are white or silver,
 Smooth surface will be highly reflective, since
it does not allow light to penetrate deeply.

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Blue end of the spectrum is at a
higher energy level than yellow
and orange.
 Colour of metals:- absorption and re-
emission of light are dependent on
wavelength.
 Gold and copper have low reflectivity at
short wavelengths, and yellow and red are
preferentially reflected.
 Silver has good reflectivity that does not
vary with wavelength, and therefore appears
very close to white.

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 Dispersions of
discrete gold
nanoparticles in
transparent media
provide fascinating
range of colors..
 In manufacture
of paints and
coatings.
 Shape of particles
and viewing
conditions determine
the color.
Colour vary depends on size……

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39. 39Blue-yellow macaw
Random Nanochannels…

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Addition of aluminium creates
brittle purple gold.
Eg:- pin, purple gold within
yellow gold ring.
 Gold colouring creating surface
oxide layers.
 Gold does not oxidize in its pure
form, base metals have to be added to
create blue, brown, and black gold.
 "Hearts" collection, in blue gold-
Ludwig Muller of Switzerland.
18 karat gold bands:-
white, pink and
green gold.
Platinum ring:- rose
gold flowers with
diamond centers and
leaves of green gold.

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Applications…….
Defence, Space, Automobiles, Agriculture, Medicine & Electronics

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Nanomaterials risks or benefits?

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Dangers of Nanotechnology
How these particles (1-100 nm) interact with environment & human body!!!!!!
 University in Texas:- Extensive brain
damage to fish exposed to fullerenes
for a period of just 48 h, (0.5 ppm).
 Changed gene markers in livers,
entire physiology was affected.
 Fullerenes killed water fleas, an
important link in the marine food chain.
Cadmium poisoning in humans:-
Cadmium selenide nanoparticles,
also called quantum dots (University
of California in San Diego, 2002).
Gold nanoparticles might move
through a mother's placenta to the
foetus (British scientist Vyan
Howard, 2004).
Nanoparticles used in sunscreen
created free radicals that damaged
DNA. (Scientists at Oxford, 1994).
Ability to interact with other living systems increases….
 Easily cross the skin, lung, and in some cases the blood/brain barriers.
 Once inside the body, there may be further biochemical reactions like the
creation of free radicals that damage cells.

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 Sewage system into the natural water cycle…
 Reduce the quantity of beneficial microorganisms..
 Green turn into partially red!!!!!
Toxicity!
 Sunscreens
 Cosmetics
 Moisturizers
 Facial Soaps/washes
 Presence of nanoparticles produces reactive oxygen species (ROS) when
entering a punctured skin membrane
 which are basically cancer causing free radicals

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Good Readings…..
http://dictionary.reference.com/browse/nanotechnology
http://entrance-exam.net/nanotechnology-value-and-scope-of-
nanotechnology-in-india/
http://en.wikipedia.org/wiki/Nanotechnology
Information Technology Age: 1990- 2020
Nano Technology Age: 2025-2050