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1. UTTAR PRADESH TEXTILE TECHNOLOGY INSTITUTE
KANPUR
SUBMITTED TO – PRESENTED BY -
SHIV KUMAR KANNAUJIYA
Dr. MUKESH KUMAR SINGH HIMANSHU JAISWAL
ARUN KUMAR

3. ABSTRACT
Currently, there are three techniques available for the synthesis of nanofibers
1. electro spinning, 2. self-assembly, and 3. phase separation.
Of these techniques, electro spinning is the most widely studied technique and
has also demonstrated the most promising results in terms of tissue engineering
applications .
The availability of a wide range of natural and synthetic biomaterials has
broadened the scope for development of nanofibres scaffolds, especially using the
electro spinning technique.
The three dimensional synthetic biodegradable scaffolds designed using
nanofibers serve as an excellent framework for cell adhesion, proliferation and
differentiation.
Keywords: electro spinning, phase separation, self-assembly, nanofiber,
biomaterial, tissue engineering, scaffold, drug delivery.

4. i
INTRODUCTION
The nonwoven industry generally considers nanofibers as having a diameter of less than
one micron, although the National Science Foundation (NSF) defines nanofibers as
having at least one dimension of 100 nanometer (nm) or less. The name derives from the
nanometer, a scientific measurement unit representing a billionth of a meter, or three to
four atoms wide. Nanofibers are an exciting new class of material used for several value
added applications such as medical, filtration, barrier, wipes, personal care, composite,
garments, insulation, and energy storage. Special properties of nanofibers make them
suitable for a wide range of applications from medical to consumer products and
industrial to high-tech applications for aerospace, capacitors, transistors, drug delivery
systems, battery separators, energy storage, fuel cells, and information technology .
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 hundred
nano meters . This method has been known since 1934 when the first patent on electros
pinning 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.
At present the production rate of this process is low and measured in grams per hour.

5. HYSTRY OF NANOFIBRES
The first attempts at nanofiber production were carried out between 1934
and 1944.
Formhals published the first patent at this time describing the
experimental production of nanofibers.
The next step was taken in 1966 by Professor Harold L. Simons, who
patented an instrument for producing ultra-thin and ultra light nanofibers
fabrics with various patterns.
In 1971 Professor Peter K Baumgartner made a device for the spinning of
acrylic fibers with a diameter of 0.05 – 1.1 microns. The work of these
inventors, and in particular their followers Professors Darrell.
The first technology enabling the production of nanofibers appeared on the
global market in the 1980s. Donaldson, one of the leading companies in
nanofibers based applications brought out the nanofibers first time for
advanced commercial applications such as air filtration technology in 1981.
The nanofibers presence showed apromise in reducing operating costs and
improved efficiency.

6. ELECTROSPINNING PROCESS
The process makes use of electrostatic and mechanical force to spin fibers from the tip
of a fine orifice or spinneret. The spinneret is maintained at positive or negative charge
by a DC power supply. When the electrostatic repelling force overcomes the surface
tension force of the polymer solution, the liquid spills out of the spinneret and forms an
extremely fine continuous filament.
It has the misleading appearance of forming multiple filaments from one spinneret
nozzle, but current theory is that the filaments do not split.
These filaments are collected onto a rotating or stationary collector with an electrode
beneath of the opposite charge to that of the spinneret where they accumulate and bond
together to form nanofiber fabric.
The distance between the spinneret nozzle and the collector generally varies from 15–30
cm.
The process can be carried out at room temperature unless heat is required to keep the
polymer in liquid state.
The final fiber properties depend on polymer type and operating conditions. Fiber
fineness can be generally regulated from ten to a thousand nanometers in diameter .

8. POLYMER-SOLVENTS USED IN ELECTROSPINNING
The polymer is usually dissolved in suitable solvent and spun from solution.
Nanofibers in the range of 10-to 2000 nm diameter can be achieved by choosing the
appropriate polymer solvent system .
POLYMER SOLVENTS
POLYMER SOLVENTS
Nylon 6 and nylon 66 Formic Acid
Nylon 6 and nylon 66 Formic Acid
Polyacrylonitrile Poly acrylonitrile Dimethyl Dimethyl formaldehyde
formaldehyde
PET PVA Trifluoroacetic Water
acid/Dimethyl chloride
PVA Water
Polystyrene DMF/Toluene
Polystyrene DMF/Toluene
Nylon-6-co-polyamide Formic acid
Nylon-6-co-polyamide Formic acid
Poly Polyramide benzimidazole Sulfuric acid
Dimethyl acetamide
Polyramide Polyimides Phenol
Sulfuric acid
Polyimides
Phenol

9. NANOFIBERS FROM SPLITTING BICOMPONENT FIBERS
As described above, nanofibers are also manufactured by splitting of
bicomponent fibers; most often bicomponent fibers are used in this
technique are islands-in-a-sea, and segmented pie structures.
Bicomponent fibers are split with the help of the high forces of air or
water jets.
Figure shows the bicomponent nanofiber before and after splitting.
A pack of 198 filaments in single islands is divided into individual
filaments of 0.9 μm. In this example, Hills Inc has succeeded in
producing fibers with up to 1000 islands at normal spinning rates.
Furthermore bi-component fibers of 600 islands have been divided
into individual fibers of 300 nm .

10. PROPERTIES OF NANOFIBERS
Nanofibers exhibit special properties mainly due to extremely high surface to weight ratio
compared to conventional nonwovens.
Low density, large surface area to mass, high pore volume, and tight pore size make the
nanofiber nonwoven appropriate for a wide range of filtration applications
In Figure 1 shows how much smaller nanofibers are compared to a human hair, which is
50-150 μm.
Figure 2 shows the size of a pollen particle compared to nanofibers.
The elastic modulus of polymeric nanofibers of less than 350 nm is found to be 1.0±0.2
Gpa. figure1 figure 2

11. APPLICATIONS OF NANOFIBERS
1 FILTRATION-Nanofibers
have significant applications in the area of filtration since their surface area is
substantially greater and have smaller micro pores than melt blown (MB)webs.
High porous structure with high surface area makes them ideally suited for many
filtration applications.
Fibre type Fibre size
In micrometre
Fibre surface area
per mass of fibre
material m2/g
Nanofibers 0.05 80
Spunbond fiber 20 0.2
Melt blown fiber 2.0 2

12. 2. MEDICAL APPLICATION
Nanofibers are also used in medical applications, which include, drug and gene delivery,
artificial blood vessels, artificial organs, and medical facemasks.
For example, carbon fiber hollow nano tubes, smaller than blood cells, have potential to
carry drugs in to blood cells.
Nanofibers and webs are capable of delivering medicines directly to internal tissues.
Anti-adhesion materials made of cellulose are already available from companies such as
Johnson & Johnson and Genzyme Corporation .
Researchers have spun a fiber from a compound naturally present in blood. This
nanofiber can be used as varieties of medical applications such as bandages or sutures
that ultimately dissolve in to body. This nanofiber minimizes infection rate, blood lose
and is also absorbed by the body.

13. Nanofibers and business
Nanofibers offer hope in finding solutions for fundamental problems in the
development of human society – the cleaning and production of drinking
water, mobile sources of energy, batteries enabling advanced energy
storage.
These are problems which directly concern millions of people.
this huge potential demand represents a great business opportunity.
Demand for products containing nanofibers is expected to grow by as
much as 40%.
The business potential of nanofibers is further enhanced by the fact that,
unlike nanoparticles, nanofibers with dimensions over 100 nm are not
regulated, even in the EU, and are potentially suitable for use in the food
industry .
It play crucial part in industry economy….
Events Expert Services
Company Profiles Researchers Profiles
Liquid Filtration Environment
Energy Advanced Materials
Food and Packaging Health & Personal Care

14. CHALLENGES IN NANOFIBERS
The process of making nanofibers is quite expensive compared to conventional fibers due
to low production rate and high cost of technology.
In addition the vapors emitting from electro spinning solution while forming the web
need to be recovered or disposed of in an environmental friendly manner.
This involves additional equipment and cost.
The fineness of fiber and evaporated vapour also raises much concern over possible
health hazard due to inhalation of fibers.
Thus the challenges faced can be summarized
1 economics
2 health hazard
3 solvent vapour
4 packaging shipping handling

15. CONCLUSSION
Mimicking the architecture of ECM is one of the major challenges of tissue engineering.
Amongst all the approaches used to prepare ECM synthetically, the approach using
nanofibers has shown the most promising results.
Nanofibers can be formed using either one of the three prevailing techniques: electro
spinning, self assembly, or phase separation. Electro spinning is the most widely studied
technique and has also shown the most promising results.
The availability of a large range of natural and synthetic biomaterials has fueled the area
of nanofiber synthesis, especially using the electro spinning technique.
REFERENCES
1. Textile World “Nano Technology and Nonwoven”. P52, November 2003.
2. Gajanan Bhat and Youneung Lee, “Recent advancements in Electrospun nanofibers.”
Proceedings of the twelfth international symposium of Processing and Fabrication of
Advanced materials, Ed TS Srivatsan & RA Vain, TMS, 2003.
3. Electrostatic spinning of Nanofibers spin Technologies, Chattanooga, TN.
4. Www.nano21c.com, Nano Techniques Co., Ltd. “Mass production of Electro spun
Nanofibers for filtration

16. THANK YOU