The Use of Electrospinning to Manufacture Ordered Nanofiber Material

By AZoNano.com Staff Writers

Topics Covered

Introduction
Electrospinning Process
Production of Ordered Nanofibre Structures
Rotary Collector
Static Patterned Collector
Split Rotary Collector
Conclusion
About Contipro

Introduction

Over the last few years, nanotechnology has made significant progress and nanofibers in particular have attracted considerable attention because of the structures they produce in one- or three-dimensional format.

These fibers have a large surface-to-volume ratio, which means they can possibly be used to enhance current technology and may pave the way for deployment in new areas. Among the various techniques of producing nanofibers, electrospinning happens to be the most universal technique. Unlike other methods of nanofibre preparation, electrospinning helps in producing fibers with different forms of structure.

Electrospinning Process

A relatively traditional technique, electrospinning was first patented in 1934 (Formhals). The primary principle of the process lies in the effect that high voltage has on a polymer solution, producing nanofibre structures with a fibre diameter that measures only a few nanometres. With electrospinning, the movement of fibres is very complex and follows a disordered trajectory. Since the flying fibers move haphazardly, they get deposited randomly and this results in nanomaterials with a disordered structure.

Figure 1. Nanofibres.

Production of Ordered Nanofibre Structures

In a number of nanomaterial applications, the internal structure needs to be accurately ordered and the nanofibre materials must exhibit anisotropic properties. Generally, electrospinning can produce an ordered nanofibre structure either by utilizing patterned collectors or by exploiting the rotary motion of a collector.

Rotary Collector

Figure 2. Rotary Collector.

A rotary cylinder can be used to create ordered fibers. A collector that rotates at high speed can reach 5,000 rpm in the 4SPIN. It traps the flying fibre and carries it in the same direction in which it is moving. When the surface speed of the cylinder is higher, the orientation of the nanofibers will be much greater.

Static Patterned Collector

Figure 3. Static patterned collector.

It is easy to prepare uniaxially ordered nanofibers for a static collector divided into two or more conductive parts, isolated by a non-conductive gap that ranges from several hundred microns to several centimetres. The nanofibers are ordered depending on the distance between the collector’s electrodes. The best possible distance depends on the number of electrodes. The transverse component of electric force is the main factor that extends nanofibers across the gap of the static patterned collector.

This type of collector offers a number of advantages like structural simplicity and the potential of producing well-ordered nanofibers. However, the downside of this type of collector is that regularly structured materials with a greater thickness and a larger surface area cannot be produced. While thicker layers are being deposited, the electric charge reacts with the nanofibers to degrade the level of ordering and direction of the nanofibers. In order to achieve well-ordered nanofibre layers, the depositing period must take only a few minutes.

Split Rotary Collector

Figure 4. Split rotary collector.

The static split and rotary collectors have been merged to produce a split rotary collector. The carrying force compounds the transverse electrostatic force in the same direction caused by the rotating mechanism. At low speeds, the direction of fibre is ascertained mainly by the electrostatic force.

At high speeds, the mechanical forces also play a role in the ordered deposition of the fibers. Hence, the ensuing degree of nanofibre direction is increased by the combination of both these forces. This creates ordered nanofibers which are much longer than those from a static split collector. Therefore, materials having a high quality internal ordered structure, and a larger volume or surface area can be created.

Conclusion

Figure 5. Nanofibre materials.

A major issue in the development of nanofibre materials is to handle fine layers without damaging them. Collection systems make it easy to handle fine layers. Moreover, they considerably improve the extent to which nanofibre materials are ordered. Since the collecting sliding tool includes a hollow cube with piston, nanofiber materials can be joined into selected layers. Extremely thick layers can be prepared and highly precise orientation can be maintained. Also, three-dimensional materials can be produced from crossed fibers having a regular internal structure.

About Contipro

The CONTIPRO holding has been involved in the research, development and biotechnological production of active ingredients for the cosmetic and pharmaceutical industries for over twenty years. With excellent production quality and extensive research facilities, it is one of the world’s leading manufacturers of hyaluronic acid and derived applications.

The holding places a huge emphasis on innovation and in-house research, which explains why almost half of its employees are R&D lab experts.

The oldest of the holding’s companies, Contipro Pharma, specializes in the manufacture of sodium hyaluronate pharmaceutical grade and other active substances for the pharmaceutical industry and finished pharmaceutical products made from hyaluronic acid.

Contipro Biotech, which produces hyaluronic acid cosmetic grade and other active ingredients for products to counter the effects of skin ageing, was founded in 1997.

In 2013 Contipro Biotech introduced the laboratory device for the nanofiber production - 4SPIN.

This information has been sourced, reviewed and adapted from materials provided by Contipro Group.

For more information on this source, please visit Contipro Group.

Date Added: Sep 18, 2013 | Updated: Sep 19, 2013
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