The document summarizes research into the relationship between the number of Taylor cones and the life of jets during roller electrospinning. It finds that as the number of Taylor cones increases, the life of jets decreases, affecting spinning performance and fiber morphology. However, salty polyvinyl alcohol solutions behave differently, with jet life initially decreasing but then increasing at salt concentrations over 0.3% due to changes in the thickness of the solution layer on the roller surface. The number of Taylor cones and thickness of the solution layer both impact the life of jets, influencing the production of nanofiber materials.

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RELATION BETWEEN NUMBER OF TAYLOR CONE AND LIFE OF JET
ON THE ROLLER ELECTROSPINNING
B. YALCINKAYA1
, F. YENER1
, F. Cengiz-CALLIOGLU2
, and O. JIRSAK1
1
Nonwoven Department of Textile Engineering Faculty, Technical University of Liberec,
Studentska 2, 46117, Czech Republic
2
Suleyman Demirel University, Engineering Faculty, Department of Textile Engineering, Cunur,
Isparta.
baturalpyalcinkaya@hotmail.com
Abstract: Electrospinning is one the unique method to procure nanofibers at submicron. Roller
electrospinning and needle electrospinning are most common way to obtain nanofiber based layers. It is
possible to produce large scale nanofibers on roller electrospinning compared with needle electrospinning.
Based on productivity of roller electrospinning, Taylor cone and life of jet which are the most important
dependent parameters were studied. Polyvinyl alcohol and polyurethane and their salty solutions were used
to investigate of Taylor cone structure on roller surface. As a result, while Taylor cone number was
increasing life of jet decreased. However the salty solutions of PVA showed different behaviour. By adding
salt firstly it was observed that life of jet decresed, however, increasing salt concentration more than 0.3%,
life of jet started to increase. The results were correlated with solution thickness onto roller surface. Results
show that solution thickness has important effect on the life of jet.
Keywords: Roller electrospinning, nanofibers, Taylor cone, life of jet, solution thickness.
1. Introduction
The phenomenon of electrospinning is an issue of a tug of war solution between electrostatic and capillary
forces. When a small volume of conductive liquid exposed to an electric field, the shape of liquid starts to
deform from the shape caused by surface tension alone. As the voltage is increased the electrostatic force
starts to over comes the surface tension and a cone shape begins to form with convex sides and a rounded
tip. This approaches the shape of cone called as Taylor cone [1].
Recently, a new technology has been developed by Jirsak [2] that is based on highly productive jet creation
from free liquid surfaces by self-organisation. This technology is called roller electrospinning under the brand
name of Nanospider. The cylinder rotates in a polymer solution tank. The electrostatic field organised
between the cylinder and a grounded collector enables the self-organisation of jets along the upper surface
of the cylinder and, hence, fibers collect on the supporting material. There are lots of parameters that affect
the electrospinning process. These can be divided as system and process parameters. Viscosity,
concentration, net charge density (conductivity), surface tension of the polymer fluid and molecular weight
can be shown as system parameters. Applied voltage, flow rate of polymer solution, distance between
capillary end and collector, ambient parameters and motion of collector can be shown as process
parameters [3].
In this work firstly effect of concentration and additives on the number of cones was investigated. Then
number of Taylor cone was associated with life time of a cone. Poly(vinly alcohol) PVA was used as polymer
and effects of dependent parameters such as number of Taylor cones and life of jet were observed.
1.1 Materials
Poly (vinyl alcohol) (MWD 70.000) was used in liquid form and produced by novaky, Slovakia. The solvent,
distilled water and the salt, sodium chloride (NaCl) which was purchased from Fluka, were used.
Polyurethane (PU) polymer, molecular weight is 2000g/mol was used as a polymer and dimethylformamide
used as a solvent. Salt, tetraethyleneammonium bromide (TEAB) was purchased from Fluka.
1.2 Preparation of solution blending of polymer
PVA was used in different concentrations (8 – 10 – 12 – 14 wt. %) as the material for the experiment. The %
12 PVA water solution was used to prepare various concentrations of the solutions proportional to sodium

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chloride (12 wt % PVA + 0.1 – 0.2 – 0.3 – 0.5 – 0.7 – 1.0 wt % NaCl) as the conductive additive and distilled
water as solvent. On the other hand PU solutions were prepared at various concentrations such as 15-17.5-
20 wt % PU and TEAB salt was added in different concentrations such as 0-0.4-0.8-1.27 wt %. The polymer
with different concentration of PVA and PU were blend under constant stirring about 1 day.
1.3 Methods
Solution properties were determined, ere electrospining process. Conductivities were determined by a
conductivity meter (Radelkis, OK-102/1). Rheological properties of solutions were measured using
Rheometer HAAKE RotoVisco 1. Figure 1 show the image of the system used to measure thickness of the
layer of the solutions onto the roller surface. Number (1) is the rotating roller with a diameter of 20.0 mm,
driven by the electrical motor, (2) is the pan filled with polymer solution, (3) is the micrometer and (4) is the
supporting stand [4].
Figure 1. Cylinder immersed into the polymer solution.
Roller electrospinning system was used to create nanofibers. In this method, there is a roller which is
connected to high voltage supplier and top of the roller there is a collector which was grounded. When high
voltage suppliers turns on the Taylor cones are created on the roller surface towards to collector (Figure 2).
Figure 2. Schematic of roller electrospinning system[3]
Digital camera was used to observe these Taylor cones and life of jet on the roller surface in course of
spinning (Figure 3). In the picture of roller, every Taylor cones are looked like bright dot onto roller surface.
Figure 3. A view of the Taylor cone and solution jets onto roller surface
Optimum process parameters such as roller speed, roller length, distance between the electrodes, voltage
etc. were kept as stable during the spinning process of PVA solution (Table 1). Spinning conditions of
electropspinning of PU solution were arranged differently [3].

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Table 1: Process parameters of roller electrospinning
Mechanical Parameters
Process
Parameters
Environmental
Parameters
Roller
Length
(cm)
Roller
Diameter
(cm)
Roller
Speed
(rpm)
Supporting
Material
Speed
(cm/min)
Distance
Between
Electrode
(cm)
Applied
Voltage
(kV)
Humidity
(%)
Temperature
(
0
C)
14,5 2 2,5 10 12 55 30 26,4
2. Results
It is well known that PVA concentration has important effect on the viscosity of solutions however different
concentration of NaCl salt have no effect on the viscosity of the solution of constant PVA concentration.
Other side increases of NaCl salt was played significant role on the solution conductivity [4, 5]. The same
results were observed during investigation of solution properties (Figure 4).
Viscosity of PVA solutions Viscosity of 12% PVA + NaCl solutions
Conductivity of PVA solutions Conductivity of 12% PVA + NaCl solutions
Figure 4. Properties of PVA solutions
It was observed that concentration of PU and TEAB were effected viscosity and conductivity of solution.
Increases of concentration of PU and TEAB were increased viscosity and conductivity [3]. According to
viscosity of solutions, thickness of solution layer onto roller surface was shown an alteration. It is given in the
Figure 5 that increasing of PVA concentration yields to increase the thickness of solution layer ordinarily.
However NaCl salt concentration was presented the vagaries. On the contrary, there were no significant
changes on the viscosity while increasing NaCl concentration (Figure 4), thickness of solution layer was
changed irregularly onto roller surface. It observed that firstly thickness of solution layer was decreased by
adding salt then it increased by adding more salt (Figure 5). This value was calculated after repeating 10
times same experiment. Then the average values were taken [5].

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Thickness of PVA solutions layer Thickness of 12% PVA + NaCl solutions layer
Figure 5. Thickness of PVA solutions onto roller surface
Various concentration of PVA was used to intention of the increasing the spinning performance on the roller
electrospinning method. It is well know justice from researchers that increasing concentration of PVA is
increased spinning performance because of the high number of Taylor cones [4, 5]. However increasing of
NaCl salt concentration was decreasing number of Taylor cones together with spinning performance (Figure
6). It has been note that low concentration of PVA solution was created wet-fibers, in this way 8 % PVA
solution were accepted as an unsung polymer solution for calculating of Number of Taylor cone and life of
jet.
Number of Taylor cone of PVA solutions Number of Taylor cone of 12% PVA + NaCl solutions
Figure 6. Number of Taylor cone of PVA solutions
Contrary to PVA solutions, PU and their salty solutions’ Taylor cone number increased together with
increment of both polymer and salt concentrations. Hence, it is obvious that additive of salt in the polymer
solution of PU and PVA did not has the same effect on the spinning performance.
Figure 7 was involved life of PVA solutions jets. It is observed that in the case of PVA solutions without salt,
the life of jet decreased when the number of Taylor cone increased. The same results were observed with
PU solutions [3]. Increment of Taylor cones onto roller surface were decreased life of jet. However salty
solutions of PVA polymer were indicated different behaviour.
Life of jet of PVA solutions Life of jet of 12 % PVA + NaCl solutions

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Figure 7. Life of jet of PVA solutions
For this reason, it is investigated that what kind of parameters was effective on number of Taylor cone. Firstly
it is accepted that the main parameter was number of Taylor cone onto roller surface because all Taylor
cone needs polymer solution to supply onto roller surface. Hence if high number of Taylor cones occurs onto
roller, solution on the surface finishes swiftly and as a result cones finish. If low numbers of cones occur
onto roller surface, there will be sufficient polymer solution supply on the roller and their durability was
longer. Figure 8 is shown that electrospinning of different PVA solutions and different Taylor cone numbers.
12 % PVA solution 12 % PVA + 0.5 % NaCl solution
Figure 8. Electrospinning of different concentration of PVA solutions
Secondly it is believed that the thickness of solution layers are played also important role on the life of jet. If
the thickness of layer and life of jet of salty solution of PVA were compared, the effect of thickness of layer is
more clear (Figure 9).
Figure 9. Comparing with thickness of layer and life of jet
As mentioned above it was expected that decreasing of the spinning performance or number of Taylor cone
together with NaCl salt concentration would increase life of jet continually. However the thickness of layer
were play second role on the life of jet and as seen Figure 9, life of jet was changed similarly with thickness
of solution layer.
We observed that the life of jet which is the dependent parameter on the roller electrospinning method was
affected by number of Taylor cones and thickness of layer. Both of them were affected by concentration of
PVA polymers and NaCl salt. As a result number of Taylor cone and life of jet affected respectively spinning
performance and nanofibers morphology. Figure 10 is shown that spinning performance of PVA solution and
the behaviours of spinning performance was change in the same direction with number of Taylor cone.

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Spinning performance of PVA solutions Spinning performance of 12 % PVA + NaCl solutions
Figure 10. Spinning performance of PVA solutions
On the other side it is believed that life of jet affects nanofibers morphology such as fibers diameter and non-
fibrous area. In the all electrospining methods, solution jets need a specific time and enough distance
between electrodes to form stable jet. Dry and uniform nanofibers form in an optimum distance between
electrodes. It is possible to mention that low quality of nanofibers are achieved with short life of jet and Table
2 proves this justice.
Table 2: Morphology of PVA nanofibers
Concentration of PVA (%) 8 10 12 14
Concentarion of NaCl (%) - - - 0.1 0.2 0.3 0.5 0.7 1.0 -
Fiber diameter (nm) 145 187 227 314 324 303 289 274 251 332
Non-fibrous area (%) 1.74 0.09 0 0.32 0.29 0.22 0.2 0.19 0.11 0.6
3. Conclusion
Electrospinning of PVA and PU solutions were done using roller electrospinning. Concentrations of PVA
polymer and NaCl salt have impact effect on dependent parameters. Two dependent parameters such as
number of Taylor cone and life of jet were observed. Concentrations of additives affected number of Taylor
cone and cones were directly affected life of jet. It is indicated that both parameters have significance on the
production of nanofiber based fabric. Hereby number of Taylor cones and life of jet have a role on the
respectively spinning performance and nanofibers mophlogy.
References
[1] Taylor, S.; Proc. Roy. Soc. London. Ser. A, 1964, 280 (1382): 383.
[2] Jirsak O.; Sanetrik F.; Lukas D.; Kotek V.; Martinova L.; Chaloupek J., European Patent: EP 1 (673
493), 2004.
[3] Yalcinkaya, B.; Yener, F.; Cengiz-Callioglu, F.; Jirsak, O.; Effect of Concentration and Salt Additive on
Taylor Cone Structure. NanoCon, Czech Republic, 2012
[4] Tuan, D. A., The role of rheological properties of polymer solutions in needleless electrostatic
spinning.Liberec Technical University, Dissertation, 114p,Czech Republic. 2010.
[5] Mduduzi B, K., The study of roller electrospinning with regard to roller movement, Liberec Technical
University, Diploma thesis, 64p, Czech Republic. 2012.