Electrospinning, a broadly used technology for electrostatic fiber formation which utilizes electrical forces to produce polymer fiber with diameters ranging from 2 nm to several micrometers using polymer solutions of both natural and synthetic polymers.

1. ELECTROSPINNING
 PRESENTEDBY:- DEBASISHSAHOO
 M. PHARM1ST YEAR
 DEPARTMENTOF PHARMACEUTICS
 ISF COLLEGEOF PHARMACY, MOGA, PUNJAB

2.  INTRODUCTION
 Electrospinning, a broadly used technology for electrostatic fiber formation which utilizes electrical forces
to produce polymer fiber with diameters ranging from 2 nm to several micrometers using polymer solutions
of both natural and synthetic polymers.
 This process offers unique capabilities for producing novel natural nanofibers and fabrics with controllable
pore structure.
 This process of electrospinning has gained much attention in the last decade not only due to its versatility in
spinning a wide variety of polymeric fibers but also due to its ability to consistently produce fibers in the
submicron range that is otherwise difficult to achieve by using standard mechanical fiber-spinning
technologies.
 With smaller pores and higher surface area than regular fibers, electrospun fibers have been successfully
applied in various fields, such as, nano catalysis, tissue engineering, protective clothing, filtration,
biomedical, pharmaceutical, optical electronics, healthcare, biotechnology, defense and security, and
environmental engineering.
 It has also been reported that with the decrease of the electrospun fiber diameter there was an increase in
the number of fiber-to-fiber contacts per unit length and a decrease in the mean pore radius in the mesh.
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3. An extremely high surface-to-volume ratio
Tunable porosity
Malleability to conform to a wide variety of sizes and shapes
The ability to control the nanofiber composition to achieve the desired
results from its properties and functionality.
ADVANTAGES
OF
SPUN NANOFIBER
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4. HISTORY OF ELECTROSPINNING
 In the late 16th century William Gilbert set out to describe the behavior of magnetic and electrostatic phenomena.
 He observed that when a suitably electrically charged piece of amber was brought near a droplet of water it would
form a cone shape and small droplets would be ejected from the tip of the cone: this is the first recorded
observation of electrospraying.
 The process of electrospinning was patented by J.F. Cooley in May 1900 and February 1902 and by W.J. Morton in
July 1902.
 Between 1964 and 1969 Sir Geoffrey Ingram Taylor produced the theoretical underpinning of electrospinning.
 Taylor’s work contributed to electrospinning by mathematically modeling the shape of the cone formed by the
fluid droplet under the effect of an electric field; this characteristic droplet shape is now known as the Taylor cone.
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5.  PROCESS
How the distribution of charge in the fibre changes
as the fiber dries during flight
Diagram showing fibre formation by electrospinning
 When a sufficiently high voltage is applied to a liquid droplet,
the body of the liquid becomes charged, and electrostatic
repulsion counteracts the surface tension and the droplet is
stretched; at a critical point a stream of liquid erupts from the
surface. This point of eruption is known as the Taylor cone.
 If the molecular cohesion of the liquid is sufficiently high,
stream breakup does not occur (if it does, droplets are electro
sprayed) and a charged liquid jet is formed.
 As the jet dries in flight, the mode of current flow changes
from ohmic to convective as the charge migrates to the surface
of the fiber.
 The jet is then elongated by a whipping process caused
by electrostatic repulsion initiated at small bends in the fiber,
until it is finally deposited on the grounded collector.
 The elongation and thinning of the fiber resulting from this
bending instability leads to the formation of uniform fibers
with nanometer-scale diameters.
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7. APPARATUS AND RANGE
 The standard laboratory setup for electrospinning
consists of a spinneret (typically a hypodermic
syringe needle) connected to a high-voltage (5 to 50 kV)
direct current power supply, a syringe pump, and a
grounded collector.
 A polymer solution, sol-gel, particulate suspension or
melt is loaded into the syringe and this liquid is
extruded from the needle tip at a constant rate by a
syringe pump.
 Alternatively, the droplet at the tip of the spinneret
can be replenished by feeding from a header tank
providing a constant feed pressure.
 This constant pressure type feed works better for lower
viscosity feedstocks.
Electrospinning/electrospraying schematic with
variations for different processing outcomes.
A constant pressure laboratory electrospinning
machine (set up for horizontal fiber production)
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8. TAYLOR CONE THEORY
 In 1964 Sir Geoffrey Ingram Taylor established the taylor cone theory to describe the deformation of small
volume liquid under the high electric field .
 As a small volume of electrically conductive liquid is exposed to an electric field, stable shape can acquired
owing the equilibrium of the electric force and the surface tension in case of Newtonian and viscoelastic liquid .
 As the voltage is increased to its critical potential and any further increase in potential will destroy the
equilibrium, thus the liquid body acquire a conical shape , with half angle of 49.3º( a whole angle of 98.6º),
referred to as taylor cone.
 Taylor cone Based on two assumptions:-
1. The surface of the cone is an equipotential surface.
2. The cone exists in steady state equilibrium.
U c =4H2/L2 {(ln2L/R) – (3/2)} (0.117πγR)
U c =Voltage
H =Distance between the tip of syringe and the
collector
L =Length of the syringe
R =Diameter of the tip of the syringe
γ =Surface tension of solution
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9. POLYMERS USED IN THIS PROCESS
SOLVENTS USED IN THIS PROCESS
SUITABLE SOLVENT SYSTEMS FOR POLYMER
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10. Electrospinning parameters (solution, processing and ambient) and their effects
on fiber morphology.
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11. CHARACTERIZATIONS OF ELECTROSPUN
NANOFIBERS
 The characterization of fibers produced by the electrospinning process remains one of the most
difficult tasks as the chances of getting single fibers are rare.
 Generally in electrospinning, the spun fibers are characterized into three distinct categories:
1. Geometrical characterization
2. Chemical characterization
3. Mechanical characterization
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12.  Geometrical characterizations
 Geometric properties of nanofibers include
fiber diameter, diameter distribution , fiber
orientation, and fiber morphology.
 For the characterization of geometric
properties, techniques such as scanning
electron microscopy (SEM), field emission
scanning electron microscopy (FESEM),
transmission electron microscopy (TEM), and
atomic force microscopy (AFM) are used.
 Mechanical characterizations
 Precise measurement of mechanical
properties of the nanofibrous matrix is
crucial, especially for biomedical
applications.
 Mechanical characterization is achieved by
applying tensile test loads to specimens
prepared from the electrospun process.
 Mechanical characterization of nanofibers
can be done by nanoindentation, bending
tests, resonance frequency measurements,
and microscale tension tests.
 Chemical characterizations
 By using this, not only the structure of the two
materials can be detected but the
intermolecular interaction can be determined
by the use of these methods.
 The characterization of the molecular
structure of a nanofiber can be done by
Fourier transform infra red (FTIR) and
nuclear magnetic resonance (NMR)
techniques.
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13.  APPLICATIONS 12

14. CONCLUSION
 Electrospinning is a simple, versatile, and cost-effective technology which generates non-woven fibers with
high surface area to volume ratio, porosity and tunable porosity.
 Melt electrospinning, an alternative means of electrospinning , apart from solution, is also available that is
done with polymer melts, which alleviates the requirement of solvents.
 Despite of several advantages and success of electrospinning there are some critical limitations in this
process such as small pore size and lack of proper cellular infiltration inside the fibers.
 In general, the electrospinning process shows excellent promise for tissue engineering and regenerative
medicine.
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16. REFERENCE
 Bhardwaj, Nandana, and Subhas C. Kundu. "Electrospinning: a fascinating fiber fabrication
technique." Biotechnology advances 28.3 (2010): 325-347.
 Wen, Peng, et al. "Electrospinning: A novel nano-encapsulation approach for bioactive
compounds." Trends in Food Science & Technology 70 (2017): 56-68.
 Chen, Shixuan, et al. "Electrospinning: An enabling nanotechnology platform for drug delivery and
regenerative medicine." Advanced drug delivery reviews 132 (2018): 188-213.
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