Nanoparticles: Present and Future Uses

© Boardworks Ltd 2007
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Nanotechnology in the media

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What is nanotechnology?
Nanotechnology involves the study and use of extremely
small substances, often called nanoparticles.
Nanoparticles are very
small, less than 100nm
across, but just how
small is that?
The word ‘nano’ comes
from the Greek word
which means ‘dwarf’.
A nanometre (nm) is
0.000 000 001metre
(or 10-9 m). That’s one
millionth of a millimetre.

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How small is nanotechnology?

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When did nanotechnology start?
Nanotechnology is not a new idea. Nanoparticles have in
fact been used by people for thousands of years.
The Egyptians used ink
containing nanoparticles of
black pigment.
Nanoparticles of gold and silver have
also been used since the 10th century
to colour ceramics and stained glass.
Nanoparticles of lead sulfide
were used by the Romans to
dye their hair black.

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Are there nanoparticles in nature?
Natural nanoparticles also exist. For example:
Nanotechnology scientists try to copy natural
nanoparticles to make new materials that are useful.
 Insects and lizards are able
to stick to walls because of the
nanostructures on their feet.
 Butterflies’ wings contain
shiny reflective nanocrystals.
 Spiders’ webs are made of
super-strong nanofibres.
 Chloroplasts in plant cells are
nanofactories that harness the
Sun’s energy to make glucose.

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When did modern nanotechnology start?
The idea of nanotechnology was
suggested in 1959 by Richard
Feynman, an American physicist.
The prize was claimed just a
year later by Bill McLellan, a
scientist working in California.
He offered a $1000 prize for the
first working motor less than
1/64th of an inch across (smaller
than a pinhead).
Scientists have since made structures smaller and smaller.
This work is now called nanotechnology, a term first used
in 1974 by Norio Taniguchi, a materials scientist in Japan.

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How has nanotechnology developed?
As scientists have steadily made things smaller, they have
needed new pieces of equipment to help them.
In 1989, an STM was used to
move 35 xenon atoms onto a
tiny piece of nickel.
In 1981, the scanning tunnelling microscope (STM) was
invented and allowed scientists to see the nano-world.
Using an STM, it is possible to see individual atoms and even
move them around.
The atoms spelled the name of
the company that the scientists
worked for. What was it called?

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Properties of nanoparticles – movement
Forces affect nanoparticles more because of their small size.
Imagine being the size of a nanoparticle and going for a swim!
 Swimming would feel like being
in treacle because it is hard for
such tiny particles to move
through water molecules.
 Nanoparticles are so small that
gravity has much less effect on
them. So if you tried to jump
into the pool, you might not go
in the direction expected.
 Walking to the pool would be difficult because air particles
would bump into you and knock you all over the place.

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Properties of nanoparticles – appearance
Nanoparticles also interact
differently with light.
Normally, gold metal appears gold
in colour. However, nanoparticles
of gold in solution appear red and
blue in colour.
Different-sized nanoparticles
of gold give different coloured
solutions.
Smaller nanoparticles appear
red in solution, while slightly
larger nanoparticles appear
blue.

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Properties of nanoparticles – surface area
Nanoparticles have a much bigger surface area to volume
ratio than larger particles.
Nanoparticles have more atoms or molecules nearer the
surface than larger particles.
low surface area
to volume ratio
high surface area
to volume ratio
This is very useful for substances such as catalysts.
In reactions, nanoparticles are able to react more quickly.
This is because more atoms in a nanoparticle can be in
contact with the reactant, than in a larger particle.

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Nanotechnology – true or false?

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How are nanoparticles made?

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Using nanoparticles – health
Nanoparticles are already used in various ways.
Plasters and bandages can contain
nanocrystals of silver, because it is toxic
to bacteria. Silver can even be woven into
athletes' socks to kill the bacteria that
makes socks smell.
Sunscreen contains nanoparticles of zinc
oxide and titanium oxide, which absorb
and reflect harmful UV rays from the Sun.
These particles are so small that they are
invisible on the skin. Before nanoparticles,
the oxide particles were big enough to be
seen, so the sunscreen looked white on skin.

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Using nanoparticles – cleaning
Nanoparticles can also help to keep things clean.
Could dirty football shirts be a thing of the past?
Fabrics have been
developed with nano-
coatings, which repel
liquid and resist stains.
Windows that are self-cleaning have been developed by
British scientists. How could self-cleaning windows work?
Spillages on treated
fabrics will not soak into
the fabric, but form beads
of liquid, which can
simply be wiped away.

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Using nanoparticles – glass

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Methods of making nanoparticles

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What are fullerenes?
The element carbon can exist in different structural forms,
which are known as allotropes.
Carbon can also exist in other forms,
collectively called fullerenes.
Diamond and
graphite are the
two most common
allotropes of
carbon.
The first of these, buckminsterfullerene,
was discovered by accident, in 1985,
and its discovery opened up a whole
new area of chemistry.

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How was buckminsterfullerene discovered?

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What are the physical properties of C60?
 It is a black solid at room
temperature which does
not conduct electricity.
The physical properties of buckminsterfullerene are:
 It is insoluble in water
but dissolves in petrol to
form a deep red solution.
 Its molecules are strong
and hard, but elastic, like
a football. They can be
squashed to 70% of their
normal size, but bounce back.

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What are the chemical properties of C60?
The chemical properties of buckminsterfullerene include:
 The molecules can be used as
cages to trap atoms and
smaller molecules inside them.
 The molecules can be joined
together to make bigger
fullerene structures.
 The surface of C60 molecules
can be coated with other atoms.
For example, coating with
hydrogen makes a smooth
substance that is even more
slippery than Teflon.

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More about fullerenes
C60 molecules are also known
as ‘buckyballs’.
 C70 molecules, which are
shaped like a rugby ball.
 Buckybabies, with less than
sixty carbon atoms.
 Fuzzyballs, with a coating
of hydrogen atoms.
 Giant fullerenes, with many
more than sixty carbon atoms.
Since the discovery of this first
fullerene, other types of fullerenes
that have been made include:

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What are the uses of fullerenes?
 Non-stick slippery coatings
for machinery, which act like
miniature ball bearings.
Some of the uses of fullerenes that scientists are currently
working on include:
 Cages to hold drug molecules
that can be delivered directly
into the body.
 Molecular sieves, which traps large particles like viruses
while allowing smaller, healthy particles to pass through.
 Chemical sponges to soak up toxic substances in the body.

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What are nanotubes?
Nanotubes are another form of fullerene.
They are tubes of carbon hexagons, like
sheets of graphite rolled into cylinders.
Nanotubes have many useful properties,
including:
 very high tensile strength
 unique electrical properties
 good heat conductance.
Multi-walled nanotubes exist. In these, several tubes can
rotate and slide within in each other, almost without friction.
Metal atoms can be attached to the outer surface of the tubes.
With these properties, what might nanotubes be used for?

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What are the uses of nanotubes?
The properties of nanotubes make them useful in many ways.
 Thinner, lighter TV screens.
 Strong, light waterproof fabrics.
 Smaller, thinner optical fibres.
 Smaller, lighter electrical circuits.
 Stronger building materials.
Some examples include:

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Missing words on fullerenes

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Future uses of nanoparticles
How might nanotechnology be useful in the future?

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Future uses of nanoparticles – medicine
There are many possible medical uses of nanotechnology.
 Nano-capsules of drugs that will target
cancer cells only.
 Nano-electronic implants in the retinas
of blind people, which communicate with
cells, making it possible for them to see.
 Nano-coatings on hip and joint
replacements to prevent rejection.
 Nano-scaffolds will be able to support
the growth of new skin and body tissue.
 Nano-sensors inside clothes, or even
inside our bodies, that will be able to run
health checks or deliver medicine.

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More future uses of nanoparticles
Other future uses of nanotechnology include:
 Nano-scale microchips and wires
for smaller electrical devices.
 Nano-scale solar cells to trap solar
energy, mimicking photosynthesis.
 Nano-size containers to store
hydrogen, being used as a fuel.
 Paints and glues containing
nanoparticles will be lighter,
stronger and need less solvents.
 Composite materials made
from nanostructures, which are
stronger, harder and lighter.

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Using nanoparticles: current or future?

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Is nanotechnology safe?
As nanotechnology becomes
more commonplace, how
careful do we need to be?
What problems might be associated with nanotechnology?
Do you think this is a realistic possibility?
In 1986, a researcher called
Eric Drexler made a prediction
about nanoparticles in the
future.
He suggested that because nanoparticles can build
themselves into molecules by self-assembly, self-replicating
nano-robots will consume the atoms of the world as they
replicate, eventually turning everything into a “grey goo”.

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People’s opinions on nanotechnology

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Nanotechnology – harmful or beneficial?

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Is nanotechnology worth developing?

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Glossary (1/2)
 allotrope – A structurally different form of an element,
which has different physical properties.
 bottom-up – A method of building up nanoparticles one
atom at a time.
 buckminsterfullerene – The hollow, spherical fullerene
molecule made up of 60 carbons atoms.
 fullerenes – The family of carbon allotropes, in which the
atoms are joined together to make hollow spheres or tubes.
 nanometre – A measurement equal to 0.000 000 001
metres.

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Glossary (2/2)
 nanoparticle – A particle which measures less than 100
nanometres in size.
 nanotechnology – The study of nanoparticles and their
uses.
 nanotubes – Fullerene molecules made of carbon atoms
arranged into hollow cylinders.
 self-assembly – A method of building nanoparticles in
which atoms and molecules arrange themselves.
 top-down – A method of making nanoparticles by starting
with larger particles and shaping them into smaller pieces.

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Nanoparticles: Present and Future Uses

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