1.2.3.2.1 Stationary spinnerets

jet is formed at the charged surface of the bubble. Very fine nanofibers are deposited on collector that is placed at the top of the polymer container (Table 3).

In this electrospinning setup, two layers were used: the lower layer was ferromagnetic and the upper layer was polymer solution (Table 4). When electrospinning

Year Author Setup Morphology Fiber bundling/

Higham Polyvinyl alcohol

A. The polymer arrangement was filled; the supply and the stature of fluid surface were higher than that of electrode and tube. By turning on gradually the pneumatic weight control valve, we could discover a few air pockets created at the pinnacle of tube. The delivered air pockets will be broken down into smaller ones on the arrangement surface. At the point when surface strain of the little air pockets lessens to the basic esteem which can be overcome by the connected electric field, nano-planes discharge from the peak of the air pockets. Nanofibers that are produced from this method

B. This is a new method to produce nanofiber with a single bubble electrospinning process which is a concept based on keeping the bubble from bursting during electrospinning. Compress gas was supplied to porous surface. This porous surface was placed below the polymer solution. When gas was supplied to this surface, bubbles were produced that

Year Author Setup Morphology Fiber bundling/polymer

polymer

in N,N-

50 nm

(PVA) was used as polymer. Production rate was 300 times more than syringe electrospinning

Polyethylene oxide in water-ethanol mixture was used in this setup. Production is 12 times more than traditional needle electrospinning

Polyacrylonitrile (PAN) was dissolved

dimethylformamide (DMF) solvent, and the weight concentration was 12 wt%. Bubble electrospinning leads to different little rises on surface with little surface tension; minimum diameter achieved with this setup was

1.2.3.1.2 Free solution spinning methods

Nanorods and Nanocomposites

A. 2008

B. 2014

Table 3.

A. 2004

Table 4.

238

have very fine diameter of 50 nm [43].

formed charged polymer jets [44].

Bubble electrospinning methods.

Yarin et al.

Free solution electrospinning methods.

Ji-Huan et al.

In this needleless electrospinning method, stationary spinneret is used for nanofiber generation. High voltage is applied to spinneret, and there is special mechanism to feed polymer solution on spinneret. Polymer jets are formed on the edges of stationary spinneret that produce nanofibers. Stationary spinnerets are further classified into three categories depending upon the spinneret position:

Horizontal stationary spinnerets. Downward stationary spinnerets. Upward stationary spinnerets.


A. In this setup solid porous polyethylene tube was used as a spinneret that fixed vertically inside tube polymer solution was filled that ejected from outside pores by applying pressurized air that formed drops on the outer surface of tube wall. This porous tube was surrounded by circular wire mesh collector. When high voltage was applied, charged drops form nanofibers. When length of the tube increased, production of nanofibers increased by 4.2 g/min per meter length of tube [2].

B. The edge of a flat plate has been utilized as a spinneret onto which polymer solution was set as beads or experiences a gravity-helped stream. When high voltage was applied, nanofibers were ejected from the edge of plates. Collector was placed vertically at a working distance [27].

C. In this electrospinning setup, twisted wire was used that was placed vertically connected with high-voltage power supply. Cylindrical collector was used to collect nanofiber placed around the wire. Polymer solution was flowing downward on the twisted wire. Multi-jets were formed at the wire that produced nanofibers [46].

#### Table 5.

Horizontal stationary spinneret methods.

## 1.2.3.2.1.1 Horizontal stationary spinnerets

In horizontal stationary spinnerets, polymer jets are formed in horizontal direction. Nanofibers are collected on vertical mounted plates. Some of these are given in Table 5.

1.2.3.2.1.2 Downward stationary spinnerets

Classification of Electrospinning Methods DOI: http://dx.doi.org/10.5772/intechopen.88654

1.2.3.2.1.3 Upward stationary spinnerets methods

described in Table 6.

tion constant [50].

horizontally [28].

Jiang et al.

Upward stationary spinnerets methods.

A. 2014

Table 7.

241

1.2.3.2.2 Rotating spinnerets

into three categories that are given below:

Horizontal rotating spinnerets Downward rotating spinnerets Upward rotating spinnerets

1.2.3.2.2.1 Horizontal rotating spinnerets

In downward stationary spinnerets, nanofibers are made in downward direction. Polymer solution is placed in shower-like spinnerets, polymer jets are stretched downward due to high voltage, and nanofibers are collected on the plate that was placed in the bottom. Some of these types of spinnerets are

In this needleless electrospinning setup, a novel spinneret was used that have a stepped pyramid shape (Table 7). When electric field was applied to the system, then nanofibers were generated from the edges of stepped pyramid-shaped spinneret. These nanofibers were collected on the collector that was negatively charged, placed at the top of the spinneret. Nanofiber production increased by increasing applied voltage and keeping working distance and concentration of polymer solu-

In this needleless electrospinning method, the spinneret is rotated in polymer solution that licks polymer solution into its surface. When high voltage is applied to the spinneret, polymer jets are formed on the surface of spinneret, and nanofibers are formed that are deposited on the collector. Rotating spinnerets are further classified

In this setup a metal roller was used as spinneret that was connected with high-voltage power supply (Table 8). Polymer solution was splashed onto metal roller through a hole of the solution provider that was placed above the metal roller spinneret. Nanofibers were collected on a metal collector that was placed

Year Author Setup Morphology Fiber

bundling/ polymer

Polyvinyl alcohol is used as polymer; with concentration 8–10%, production of nanofiber is 2.46–5.84 g/h


A. In this electrospinning setup, a flat spinneret was connected to the positive point of high-voltage power supply. Polymer solution was pumped by syringe to the hollow cylindrical metallic cavity. There was a hole in the flat end surface where the solution was ejected and formed nanofibers. Nanofibers were collected on the sheet placed below [47].

B. In this novel electrospinning setup, a conical wire coil was used as spinneret. PVA solution was filled in this conical wire coil; when high voltage was applied to this cone, jets were produced from the surface of wire coil. Nanofibers were collected on the metal plate placed below the conical wire coil [25].

C. Multi-hole spinneret was used that contained electrode and thick plastic plate. This plastic plate has 19 holes which produce more uniform electric filed during electrospinning process. The polymer solution was placed between the plastic plate and electrode. Polymer was pumped by syringe. It was found that electric field lines play leading role in jet repulsion during nanofiber production [48].

D. Variable high-voltage power supply was used that is supplied to needleless inner-cone nozzle. Heating device was used to melt polypropylene, and a cylinder collector was used to collect nanofibers [49].

#### Table 6.

Downward stationary spinnerets methods.
