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SKYLINE INSTITUTE OF ENGINEERING
& TECHNOLOGY GR.NOIDA
BYASHISH SHARMA
ME-3rd YEAR
NANO FIBER
l o a d i n g l o a d i n g l o a d i n g
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Nanotechnology and Nanofibers
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Nanotechnology
The study of control of matter on an atomic
and molecular scale.
Deals with structures the size of 3300 nanometers
or smaller (33 nm = 33/33,000,000,000 m or 330-9
m).
Involves engineering on a small scale to create
smaller, cheaper, lighter, and faster devices that
can do more things with less raw materials.
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Key Dimensions in Nanometers
An atom is about 0.3 nm in size.
Typical spacing between 2carbon atoms in a molecule is
0.332 0.335 nm.
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DNA double helix has a diameterof about 2 nm.
A bacterium of the genus Mycoplasma
has a length of 200 nm.
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A red blood cell is 6,000 nm in diameter.
A human hair is 80,000 nm in diameter.
To put this scale in context, the size of a nanometerto a meter, is the same as that of a marble to the sizeof the Earth.
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Properties of Nanoparticles
Materials reduced to the nanoscale can show
different properties compared to what they
exhibit on the macroscale.
Opaque substances may become transparent
(copper); stable materials turn combustible
(aluminum); insulators become conductors(silicon); and solids turn to liquids at room
temperature (gold).
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Nanoparticles tend to be more chemically
reactive than their ordinary sized counterparts
because they have more surface area.
An increase in surface area to volume ratio alters
the mechanical, thermal, and catalytic properties
of materials.
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Model of Surface-to-Volume
Comparisons
Neglecting spaces between the smaller boxes, the volumes of the
box on the left and the boxes on the right are the same but the
surface area of the smaller boxes added together is much greater
than the single box.
Single Box Ratio
6 m2
33
m3
= 6 m2/m3
Smaller Boxes Ratio
332 m2
33 m3= 332 m2/m3
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Another Way to Think of this Ratio
Using Sugar Cubes
Each individual cube is about 33
cm on a side, so each side has
an area of 33 cm
2
. With sixsides, it has a surface area of 6
cm2 and a volume of 33 cm3.
This is a surface area to volumeratio of 6 cm2/cm3
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A block made from 64sugar cubes is 4 cm ona side and has a surfacearea of 6 x 336 cm2 or96 cm2 and a volumeof 64 cm3.
This is a surface area tovolume ratio of 33.5 cm2/cm3.
If you compute the surface of all 64 individual cubes,you would have 64 x 6cm2 or 384 cm2 or 4 times moresurface area with the same total volume.
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An Example of the Affects of
Surface-to-Volume Ratios in Animals
Larger surface-to-volume ratio
Very susceptible to changes in heat
Smaller surface-to-volume ratio
Less susceptible to changes in heat
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Applications
From videotapes to DVDs and from cathode
ray tubes to flat screen TVs, nanotechnology
applications require team efforts from
biologists, chemists, physicists, engineers, andinformation technologists.
Example: a cochlear ear implant requiresphysiologists, electronic engineers, mechanical
engineers, and biomaterials experts
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Products Currently on the Market
Using Nanotechnology
Over 600 nanotech enabled
products are on the market
today. Some examples are:
Carbon nanotubes in bike
frames and tennis rackets
make the products stronger
and lighterThis bike frame weights 2.75 pounds
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Nano-size particles of titanium dioxide and zinc oxide
are less visible than the whitish particles of the oldersunscreens. They block UV light more effectively
without turning your skin white
Older sunscreen leaves a white sheen behind
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Self cleaning glass uses UV light to energize
nanoparticles to break down and loosen dirt onglass. Particles are also hydrophilic so water spreadsacross the glass evenly and helps wash the glassclean.
Coating fabric with nanoparticles helps repel thewater and other materials to make clothes stainresistant.
Nanoparticles of silver in antimicrobial bandagesblock the microbes cellular respiration, thus killingthem.
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Nanoparticles in scratch resistant coatings are
common on everything from cars to eyeglass lenses.
Bridgestone engineers developed a Quick Response
Liquid Powder Display, a flexible digital screen, using
nanotechnology.
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Nanofibers:What are they? Why are they important?
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What is a Nanofiber?
A nanofiber is a continuousfiber which has a diameter inthe range of billionths of ameter.
The smallest nanofibersmade today are between33.5 and 33.75 nanometers.
At the right a human hair(80,000 nanometers) isplace on a mat of nanofibers
Image from EPA.gov
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Nanofibers range in diameter of 2-600
nanometers and are very difficult to see with
the naked eye so they are studied usingmagnification
Spider dragline 3,000 nanometersElectron micrograph of nanofibers used for
tissue scaffolds
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Unique Properties of Nanofibers
Size: nanofibers are very small which gives them
unique physical and chemical properties and allows
them to be used in very small places.
Surface-to-volume ratio: nanofibers have a huge
surface area compared to their volume. So scientists
have lots of surface to work with!
The huge surface area available on a nanofiber makes it
very suitable for new technologies which require smaller
and smaller environments for chemical reactions to occur.
Increasing the surface area speeds up a chemical reaction.
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Making Nanofibers
Melt Fibers: some nanofibers can be made bymelting polymers and spinning or shooting them
through very small holes. As the fiber spins out it
stretches smaller and smaller...
Cotton candy is made by heating syrup to
a high temperature and then the liquid is
spun out through tiny holes. As the fiberspins it is pulled thinner and thinner. It
cools, hardens and, presto! Cotton
Candy!!
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Electrospinning to Make Nanofibers
An electric field pulls on
a droplet of polymer
solution at the tip of the
syringe and pulls out asmall liquid fiber. It is
pulled thinner and
thinner as it approaches
the collection plate.
Electrospinning Apparatus
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Electrospinning a Polymer Solution to
Produce Nanofibers
This picture shows the actual
spinning of a solution made of
the polymer PEO (polyethylene
oxide) dissolved in water.
Polymer solutions can be
electrospun because of their long
repeating units.
The resulting fiber is collected
below on a grounded plate
Image courtesy of Reneker Group
The University of Akron, College of Polymer Science
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Here you can see the individual fiber being pulled downward
toward the grounded collection plate.
Image courtesy of Reneker Group
The University of Akron, College of Polymer Science
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PEO (Polyethylene Oxide) Nanofibers
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Uses of Nanofibers
High surface area: Filtration, Protective clothing.
Filter applications: Oil droplet
coalescing on nanofibers increase
the capture rate of the oil fog.
Nano-Tex fabrics with water, cranberry
juice, vegetable oil, and mustard after30 minutes (left) and wiped off with
wet paper towel (right)
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Uses of Nanofibers continued.
Support: Template for
making different
structures/coatings,
catalysts/enzyme
supports.
Tissue Scaffolding:Fibroblast cells grown
on PLGA nanofibers. Image by Amy Liu, Hoover High School Student
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Uses of Nanofibers continued.
Strength: Reinforced
composites by
nanofibers, twisted in
yarns.
New yarns with
outstanding wickingproperties: Here
electrospun nylon fibers
are spun into yarns.
Image courtesy of Reneker Group
The University of Akron, College of Polymer Science
and Samantha Loutzenheiser, Hoover High School.
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Uses of Nanofibers continued.
Encapsulation: Drug delivery,
Scaffolds for growing cells,
Agriculture.
Water filtration: EDTA, achelating compound, has been
encapsulated in tecophilic
nanofibers.
These fibers in a water filter can
remove heavy metals,
particularly lead, cadmium and
copper.
Image by Joe Sinha, Hoover High School Student
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Uses of Nanofibers continued.
Light Weight: Produce Solar
sails in space, Aircraft wings,
Bullet-proof vests.
New breathable bullet-proof
vest: NomexNanofibers
Image courtesy of Reneker Group
The University of Akron, College of Polymer Science
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Uses of Nanofibers continued.
Structure: Fuel cell, Micro/Nano
electronic devices
Nanofibers can be used togreatly decrease the size of
a fuel cell while increasing
the electrical output.
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Website Resources
http://www.nanitenews.com/
http://electrospun.blogspot.com/
http://micro.magnet.fsu.edu/primer/java/
scienceopticsu/powersof330/
http://www.nnin.org/edunews_6.html
http://www.nanitenews.com/http://electrospun.blogspot.com/http://micro.magnet.fsu.edu/primer/java/%0Bscienceopticsu/powersof10/http://micro.magnet.fsu.edu/primer/java/%0Bscienceopticsu/powersof10/http://www.nnin.org/edunews_6.htmlhttp://www.nnin.org/edunews_6.htmlhttp://micro.magnet.fsu.edu/primer/java/%0Bscienceopticsu/powersof10/http://micro.magnet.fsu.edu/primer/java/%0Bscienceopticsu/powersof10/http://micro.magnet.fsu.edu/primer/java/%0Bscienceopticsu/powersof10/http://electrospun.blogspot.com/http://www.nanitenews.com/