Nanotechnology, Carbon nanotubes, chemical nanotubes

1. Nanotechnology
• "Nano" is a Greek word.
• Nanotechnology is science, engineering, and technology conducted at the
nanoscale, which is about 1 to 100 nanometers
• Put another way, this is about 1/50,000th the width of a human hair. Normal
office paper is about 100,000nm thick.
• Nanotechnologists will typically work in the range 1-100nm.
• Physicist Richard Feynman is the father of nanotechnology.

2. Future Scope
Nanotechnology is the engineering of functional systems
at the molecular scale.
This covers both current work and concepts that are more
advanced.
•Development in nanotech will affect
•Electronics
•Computing
•Medicine
•Cosmetics
•Foods
•Military
•Energy
•all walks of life.
•By 2020, $1 trillion worth of products could be nano-
engineered by nanotechnology
Nanotechnology
With 15,342 atoms, this parallel-shaft speed
reducer gear is one of the largest nanomechanical
devices ever modeled in atomic detail.

3. •Number of physical properties change when compared to macroscopic systems.
•A number of physical phenomena become noticeably pronounced as the size of the
system decreases.
•These include both statistical mechanical effects and quantum mechanical effects
•This effect does not come into play by going from macro to micro dimensions.
•Materials reduced to the nanoscale can suddenly show very different properties like
•opaque substances become transparent (copper)
•inert materials become catalysts (platinum)
•stable materials turn combustible (aluminum)
•solids turn into liquids at room temperature (gold)
•insulators become conductors (silicon)
•A material such as gold, which is chemically inert at normal scales, can serve as a
potent chemical catalyst at nanoscales.
•Nanorobotics is the technology of creating machines or robots at or
close to the scale of a nanometres (10-9
metres).
Nanotechnology

4. •Approaches in nanotechnology:
•Top-down approach
•The top-down approach is similar to making a stone statue.
•Examples of this kind of approach are
•lithographic techniques (such as photo-, ion beam-,
electron- or X-ray- lithography)
•Cutting
•Etching
•grinding.
•These techniques have been used to great effect to produce the
miniature of electronic components, such as
•computer chips,
•MEMS (micro-electromechanical systems)
Nanotechnology
Rock
Statue

5. •Bottom-up approach
•can be thought of as the same approach one would take to
building a house
•one takes lots of building blocks and puts them together to
produce the final bigger structure
•A good example of this kind of approach is found in nature; all
cells use enzymes to produce DNA by taking the component
molecules and binding them together to make the final
structure.
•Examples of this kind of approach are
•Chemical synthesis
•Self-assembly
•Molecular fabrication are all examples of bottom-up
techniques.
•Examples of structures made using bottom-up techniques.
•Cosmetics
•Fuel additives
•Experimental atomic and molecular devices
Nanotechnology
Brick
Building

6. Applications
• There are many familiar products and machines that we use every day which already rely on
nanotechnology

7. •Diagnostics
• Biological tests measuring the presence or activity of selected substances become
quicker more sensitive and more flexible when certain nanoscale particles are put
to work as tags or labels.
•Magnetic nanoparticles, bound to a suitable antibody, are used to label specific
molecules, structures or microorganisms.
•Gold nanoparticles tagged with short segments of DNA can be used for detection
of genetic sequence in a sample.
•Tissue Engineering
•Nanotechnology can help to reproduce or to repair damaged tissue.
•This so called “tissue engineering” makes use of artificially stimulated cell
proliferation by using suitable nanomaterial-based scaffolds and growth factors.
Applications

8. •Drug delivery
•The overall drug consumption and side-effects can be lowered significantly by
depositing the active agent in the morbid region only and in no higher dose than
needed.
•This highly selective approach reduces costs and human suffering.
•Some potentially important applications include cancer treatment with iron
nanoparticles or gold shells.
•Catalysis
•Chemical catalysis benefits especially from nanoparticles, due to the extremely large
surface to volume ratio.
•The application potential of nanoparticles in catalysis ranges from fuel cell to
catalytic converters and photocatalytic devices.
•Catalysis is also important for the production of chemicals.
Applications

9. •Filtration
•Nano filtration is mainly used for the removal of ions or the separation of different
fluids.
•The membrane filtration technique is named ultrafiltration, which works down to
between 10 and 100 nm.
•One important field of application for ultra filtration is medical purposes as can be
found in renal dialysis.
•Semiconductor devices
•An example of such novel devices is based on spintronics.
•The dependence of the resistance of a material (due to the spin of the electrons) on
an external field is called magnetoresistance.
•This effect can be significantly amplified (GMR - Giant Magneto-Resistance) for
nanosized objects.
•The GMR effect has led to a strong increase in the data storage density of hard disks
and made the gigabyte range possible.
Applications

10. •Lasers
•Quantum dots are nanoscaled objects, which can be used, among many other things,
for the construction of lasers.
•The advantage of a quantum dot laser over the traditional semiconductor laser is that
their emitted wavelength depends on the diameter of the dot.
•Quantum dot lasers are cheaper and offer a higher beam quality than conventional
laser diodes
•Foods
•Nanotechnology can be applied in the production, processing, safety and packaging
of food.
•A nanocomposite coating process could improve food packaging by placing anti-
microbial agents directly on the surface of the coated film.
•Nanocomposites could increase or decrease gas permeability of different fillers as is
needed for different products.
•Textiles
•The use of engineered nanofibers already makes clothes water- and stain-repellent or
wrinkle-free.
•Textiles with a nanotechnological finish can be washed less frequently
and at lower temperatures.
Applications

11. Structural
•Clothes: waterproof tear-resistant cloth fibers.
•Combat jackets: MIT is working on combat jackets that use carbon nanotubes as
ultrastrong fibers and to monitor the condition of the wearer
•.
•Concrete: In concrete, they increase the tensile strength, and halt crack
propagation.
•Polyethylene: Researchers have found that adding them to polyethylene increases
the polymer's elastic modulus by 30%.
•Sports equipment: Stronger and lighter tennis rackets, bike parts, golf balls, golf
clubs, golf shaft and baseball bats.
•Ultrahigh-speed flywheels: The high strength/weight ratio enables very high
speeds to be achieved.
•Bridges: For instance in suspension bridges (where they will be able to replace
steel), or bridges built as a "horizontal space elevator".
Applications

12. Electromagnetic
•Buckypaper - a thin sheet made from nanotubes that are 250 times stronger
than steel and 10 times lighter that could be used as a heat sink for chipboards,
a backlight for LCD screens or as a faraday cage to protect electrical
devices/aeroplanes.
•Computer circuits: A nanotube formed by joining nanotubes of two different
diameters end to end can act as a diode, suggesting the possibility of
constructing electronic computer circuits entirely out of nanotubes.
•Because of their good thermal properties, CNTs can also be used to dissipate
heat from tiny computer chips.
•The longest electricity conducting circuit is a fraction of an inch long.
(Source: June 2006 National Geographic).
•Conductive films: A 2005 paper in Science notes that drawing transparent
high strength swathes of SWNT is a functional production technique . Carbon
nanotube films are substantially more mechanically robust than ITO films,
making them ideal for high reliability touch screens and flexible displays.
Nanotube films show promise for use in displays for computers, cell phones,
PDAs, and ATMs.
Applications

13. •Light bulb filament: alternative to tungsten filaments in incandescent lamps.
•Magnets: MWNTs coated with magnetite
•Optical ignition: A layer of 29% iron enriched SWNT is placed on top of a layer of
explosive material such as PETN, and can be ignited with a regular camera flash.
•Solar cells GE's carbon nanotube diode has a photovoltaic effect. Nanotubes can
replace ITO in some solar cells to act as a transparent conductive film in solar cells
to allow light to pass to the active layers and generate photocurrent.
•Superconductor: Nanotubes have been shown to be superconducting at low
temperatures.
•Ultracapacitors: MIT is researching the use of nanotubes bound to the charge
plates of capacitors in order to dramatically increase the surface area and therefore
energy storage ability.[3]
•Displays: One use for nanotubes that has already been developed is as extremely
fine electron guns, which could be used as miniature cathode ray tubes in thin high-
brightness low-energy low-weight displays. ).
•Transistor: developed at Delft, IBM, and NEC.
Applications

14. Chemical
•Air pollution filter: Future applications of nanotube membranes include
filtering carbon dioxide from power plant emissions.
•Biotech container: Nanotubes can be opened and filled with materials such as
biological molecules, raising the possibility of applications in biotechnology.
•Hydrogen storage: Research is currently being undertaken into the potential use
of carbon nanotubes for hydrogen storage. They have the potential to store
between 4.2 and 65% hydrogen by weight. This is an important area of research,
since if they can be mass produced economically there is potential to contain the
same quantity of energy as a 50l gasoline tank in 13.2l of nanotubes.
•Water filter: Recently nanotube membranes have been developed for use in
filtration. This technique can purportedly reduce desalination costs by 75%. The
tubes are so thin that small particles (like water molecules) can pass through
them, while larger particles (such as the chloride ions in salt) are blocked.
Applications

15. • Carbon nanotube is discovered in 1991.
• It opens the new era in material science.
• These molecules have amazing electronic, magnetic and mechanical
properties.
• They are at least 100 times stronger than steel, but only one-sixth as
heavy.
• Nanotubes can conduct heat and electricity far better than copper.
Carbon Nanotubes

16. Strength
•Carbon nanotubes are one of the strongest and stiffest materials known, in
terms of tensile strength and elastic modulus respectively.
•This strength results from the covalent bonds formed between the individual
carbon atoms.
•In 2000, a multi-walled carbon nanotube was tested to have a tensile strength
of 63 GPa
•In comparison, high-carbon steel has a tensile strength of approximately
1.2 GPa.
•CNTs have very high elastic moduli, on the order of 1 TPa.
•Since carbon nanotubes have a low density for a solid of 1.3-1.4 g/cm³, its
specific strength of up to 48,462 kN·m/kg is the best of known materials,
compared to high-carbon steel's 154 kN·m/kg.
Carbon Nanotubes

17. •Under excessive tensile strain, the tubes will undergo plastic deformation,
which means the deformation is permanent.
•This deformation begins at strains of approximately 5% and can increase the
maximum strain the tube undergoes before fracture by releasing strain energy.
•CNTs are not nearly as strong under compression.
•Because of their hollow structure and high aspect ratio, they tend to undergo
buckling when placed under compressive, torsional or bending stress
Carbon Nanotubes

18. •Carbon nanotubes additionally can also be used to produce nanowires
of other chemicals, such as gold or zinc oxide.
•These nanowires in turn can be used to cast nanotubes of other
chemicals, such as gallium nitride.
•These can have very different properties from CNTs –
for example, gallium nitride nanotubes are hydrophilic,
while CNTs are hydrophobic,
giving them possible uses in organic chemistry that CNTs could not be
used for.
Chemical nanowires

19. Thank you !!!
Courtesy:
http://www.nano.gov
http://www.crnano.org
https://www.conted.ox.ac.uk