Transcript Document 7258838

Nanotechnology
A new applied science using very, very small objects.
The prefix “nano” comes from an ancient Greek word for “dwarf”.
In science and technology it indicates the dimension of one billionth
(1 thousand millionth)
What is Nanoscale Science?
The study of objects and phenomena at a very, very small scale,
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about 1 to 100 nanometres (1 nm = 10 m).
–
10 hydrogen atoms lined up measure about 1 nm
–
A grain of sand is 1 million nm, or 1 millimetre wide
An emerging, interdisciplinary science which involves;
– Physics,
– Chemistry,
– Biology,
– Engineering,
– Materials Science ,
– Computer Science
METRE

MILLIMETRE

MICROMETRE
1

1 thousandth

1 millionth

NANOMETRE
 1 thousand millionth
(1 billionth)
Nanotechnology is the creation of useful and functional materials,
devices, and systems of any size, by controlling matter at the
nanometre scale. At this scale the properties (physical, chemical and
mechanical) usually change from their bulk properties.
Just consider! 1946
First functional digital computer created
It occupied about
170 square metres, used about 18,000 vacuum tubes, and weighed almost 50 tons.
1947
The solid-state transistor was invented
A robust and very efficient
low voltage switch which
would replace valves.
A telephone looked like this
Before
1970
NO colour televisions, video
games or microprocessors
Before
1980
No desktop computers or mobile phones
Before
1990
No such thing as the
World Wide Web
Before
1994
Spam is a SPiced hAM
luncheon meat
The development of the solid state transistor (silicon chip) and computer have
led to very dramatic and rapid change for humans. They have had an impact
in many ways that were not even expected and enabled many NEW
technologies and areas of study.
The potential for NANOTECHNOLOGY is enormous with its impact
likely to be as significant and maybe cause even more changes than
the transistor and computer
Number of transistors found in silicon microprocessors (microchips)
Moore's Law - the number of transistors on a chip will double about every two years.
Today, it doubles every 12-18 months and the rate is even increasing
Actual Size
2.0 x
4.0 x
7.5 x
10 x
20 x
40 x
64 x
80 x
100 x
200 x
400 x
800 x
1000 x
The limit for LIGHT microscopes
(1200x with oil immersion lens)
1800 x
3600 x
6000 x
8000 x
10 000 x
18 000 x
32 000 x
64 000 x
82 000 x
100 000 x
200 000 x
480 000 x
640 000 x
820 000 x
1 000 000 x
We are now down to the NANOSCALE.
Think about a crowd at a rock concert bouncing large balls
Close up the view is balls bouncing about above the people.
From a distance the balls and people can’t be seen even though they are moving about
So how do we SEE and CONTROL things at the
nanoscale?
Scanning probe microscopes
Source: Scientific American, Sept. 2001
Developed during the 1980s
A new way to “see” at the nanoscale.
We can now image really small things,
like atoms, and move them too!
•
These microscopes monitor the
interactions between a probe and a
sample surface
About 25 nanometers
•
What we “see” is really a computer
generated image
•
Two types are:
– Scanning Tunneling Microscope
(STM)
– Atomic Force Microscope (AFM)
This is about how big atoms are compared
with the tip of the microscope
Scanning Tunnelling Microscopes (STMs)
• Monitors the electron tunnelling current
between a probe and a sample surface
Scanning Probe
• The electron tunnelling current varies as
the distance of the surface from the probe
changes. As the probe moves over the
surface an image of the surface is created.
• Tunnelling will only occur over very tiny
distances and relies on quantum effects.
Tip and surface and electron tunneling current
Source: http://mrsec.wisc.edu/Edetc/modules/MiddleSchool/SPM/MappingtheUnknown.pdf
Atomic Force Microscopes (AFMs)
• Monitors the forces of attraction and
repulsion between a probe and a sample
surface
• The tip is attached to a cantilever which
moves up and down in response to
forces of attraction or repulsion with the
sample surface
• Movement of the cantilever is detected
by a laser and photo-detector which
allows an image of the surface to be
created
Laser and position detector used to
measure cantilever movement
Source: www3.physik.uni-greifswald.de/method/afm/eafm.htm
So What Do We See
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Using Computer analysis of information from the microscope tip to create an image
Nickel from an STM
Graphite (Carbon) from an AFM
Sources: http://www.almaden.ibm.com/vis/stm/blue.html
http://www.physik.uni-augsburg.de/exp6/imagegallery/afmimages/afm-image-graphite.jpg
What has already been done?
IBM image made in 1990 with 35 xenon atoms laid down on a substrate
Source: www.cite-sciences.fr/.../fondements_2a.php
Nanolithography using an AFM
microscope laying down
DNA molecules to different depths
Source: www. anotech-now.com/basics.htm
Pushing atoms around one at a time
Iron (Fe) atoms
forming corral
Copper atoms (Cu)
as substrate
A new way to make things –
From the bottom up, rather than top down
• Mimicking natural processes, e.g. growth, photosynthesis.
• More efficient use of resources
• Using new properties that only occur at the nanoscale
A common example - Invisible Sunscreen
An example of MIMICKING NATURE
LOTUS Leaf
Self cleaning surface
Self-cleaning paints and fabrics
Surfaces applied with smart paint never allow
water drops to stay. They are kept clean and dry.
COURTESY: STOAG
Nanotubes In Unique Textiles
Half the threads in this textile are black carbon
nanotube threads
• Carbon nanotubes can be spun into fabric to form nanocomposite fibres
- this is currently an area of research at CSIRO, Australia
- very strong and yet lightweight fabrics are possible
• Spun carbon nanotubes can be 3x stronger than spider silk
- made by bonding carbon nanotubes with the polymer PVA.
Image: Courtesy Ray Baughman
What If?
What if your t-shirt could stop a bullet?
• Professor Liangchi Zhang at the
University of Sydney is
investigating ballistic-resistance
textiles using carbon nanotubes.
Carbon nanotubes are exceedingly strong and light cylinders. They possess 100 times the
tensile strength of steel and are six times lighter. They also combine the electrical
conductivity of copper and the thermal conductivity of diamond. They have the potential
to create super-tough, fibre-reinforced plastics and other lightweight materials.
So why do we need to know about NANOTECHNOLOGY ?
Huge potential to solve problems in creative ways
A new antireflective coating developed by researchers at Rensselaer Polytechnic
could help to overcome two major hurdles blocking the progress and wider use of
solar power. The nanoengineered coating, pictured here, boosts the amount of
sunlight captured by solar panels and allows those panels to absorb the entire
spectrum of sunlight from any angle, regardless of the sun’s position in the sky.
A huge leap has been made in the creation of high efficiency, cost effective solar
power with the the world’s first material that absorbs the entire spectrum of sunlight
(UV, visible, and infrared) from virtually any angle with near 100% efficiency.
(image credit: Credit: Rensselaer/Shawn Lin)
Nov 2008
The NOKIA MORPH mobile phone
A concept phone using nanotechnology in the design
http://www.nokia.com/about-nokia/research/demos/the-morph-concept/video
Paint that self-repairs scratches
Windows that can be tinted or clear
AccessNano website : Free website developed to provide teachers
and students with activities, experiments and worksheets to study
issues relating to nanotechnology.
www.accessnano.org
13 ready-to-use, versatile, web-based teaching modules.