Content ■ History of Nanofibers. ■ What is Nanofibers ■ Properties of Nanofibers ■ Production of Nanofibers ■ Advantage and Disadvantage of Nanofibers ■ Application of nanofibers

1. NANOFIBERS
AMAN UL AZAM KHAN
181-171-801

2. Content
■ History of Nanofibers.
■ What is Nanofibers
■ Properties of Nanofibers
■ Production of Nanofibers
■ Advantage and Disadvantage of Nanofibers
■ Application of nanofibers

3. History of Nanofibers.
■ Nanofibers were first produced via electrospinning more than four centuries ago.
Beginning of the electrospinning method, English physicist William Gilbert (1544-
1603) first documented the electrostatic attraction between liquids by preparing an
experiment in which he observed a spherical water drop on a dry surface warp into a
cone shape when it was held below an electrically charged amber.

4. What is Nanofibers
■ Nanofibers are fibers with diameters in the nanometer range. In the textile industry,
this definition is often extended to include fibers as large as 1000 nm diameter.
Nanofibers are Non-woven fabric.
■ Nanofibers range in diameter of 2-600 nanometers and are very difficult to see with
the naked eye so they are studied using magnification. There exist many different
methods to make nanofibers, including drawing, electrospinning, self-assembly,
template synthesis, and thermal-induced phase separation.

5. Properties of Nanofibers
■ Low density of nanofibers
■ Large specific surface area of nanofibers
■ Small pore size
■ High porosity – good breathability
■ Excellent mechanical properties in proportion to weight
■ Possibility to incorporate different additives.
 Surface-to-volume ratio
 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. Unique Properties of
Nanofibers

6. Production of Nanofibers
 They can be produced by,
■ Melt processing
■ Electro spinning

7. Melt processing
■ Melt” Fibers: some nanofibers can be made by melting polymers and spinning or
shooting them through very small holes. As the fiber spins out it stretches smaller
and smaller
■ The smallest nanofibers are made by electrospinning solutions of polymers
■ These solutions are place in a pipette or syringe with a small wire inserted.
■ The wire will serve as an electrode which is hooked to a high voltage power supply. A
collection plate where fibers will land and deposit is attached to the ground of the
power supply.

8. Electro spinning
■ Generally, polymeric nanofibers are produced by an electro-spinning process.
■ Electro-spinning is a process that spins fibers of diameters ranging from 10nm to
several 100nm.
■ This method has been known since 1934 when the first patent on electro- spinning
was filed.
■ Fiber properties depend on field uniformity, polymer viscosity, electric field strength
and DCD (distance between nozzle and collector). •
■ Advancements in microscopy such as scanning electron microscopy has enabled us
to better understand the structure and morphology of nanofibers.

9. Cont…
• An electric field pulls on a
droplet of polymer
• solution at the tip of the
syringe and pulls out a small
liquid fiber.
• It is pulled thinner and thinner
as it approaches the collection
plate. Electro-spinning Process

10. Cont…
• This picture shows the actual
spinning of a solution made of
the polymer PEO (polyethylene
oxide) dissolved in water.
• Polymer solutions can be electro
spun because of their long
repeating units.
• The resulting fiber is collected
below on a grounded plate
Electro-spinning Process

11. Advantage and Disadvantage of Nanofibers
Advantage
■ Inexpensive setup,
■ Ability to control many factors, such
as the fiber diameter, orientation, and
composition
■ High surface area to volume ratio
■ Ease of material combination
■ Commercial applications:
 Air filtration membrane
 Face mask
 Water filtration membrane
 Cell culture plates
 Wound care patch
Disadvantage
■ use on organic solvents
■ limited control of pore structures

12. Application of nanofibers
■ Tissue engineering
■ Drug delivery
Bone matrix composed of collagen
fibrils
Drugs and biopolymers can be loaded onto nanofibers via simple
adsorption, nanoparticles adsorption, and multilayer assembly.

13. ■ Cancer diagnosis:
CTC capture and release mechanism of third generation Thermoresponsive Chip.
Cont…

14. ■ Lithium-air battery
■ Optical sensors
 Polymer optical fibers have generated increasing interest in recent years. Because
of low cost, ease of handling, long wavelength transparency, great flexibility, and
biocompatibility, polymer optical fibers show great potential for short-distance
networking, optical sensing and power delivery
Schematic of a lithium-air battery. For the
nanofiber-based lithium-air battery, the cathode
would be made up of carbon nanofibers.
Cont…

15. ■ Air filtration: Electro spun nanofibers are useful for removing volatile organic
compounds (VOC) from the atmosphere. Scholten et al. showed that adsorption and
desorption of VOC by electro spun Nano fibrous membrane were faster than the
rates of conventional activated carbon.
Nanofiber Dry Air Filter.
Cont…

16. Cont…
■ Oil-water separation
 Nanofibre has the capabilities in oil–water separation, most particularly in sorption
process when the material in use has the oleophilic and hydrophobic surfaces.
These characteristic enable the nanofiber to be used as a tool to combat either oily
waste- water from domestic household and industrial activities, or oily seawater due
to the oil run down to the ocean from oil transportation activities and oil tank
cleaning on a vessel
■ ORTHOPEDIC AND NEURAL IMPLANTS
 Nano fibers are compatible with human tissues.
 Can create better bone & neural implants.
 Compatibility arises from similarity in body tissue and Nano structure. • Orthopedic
Nano implants – Commercially available in 5 – 10 years.
 Recently, researchers have found that nanofiber meshes could be used to fight
against the HIV-1 virus, and be able to be used as a contraception