Electrospinning

To start talking about electrospinning, let's talk a little about its history. In 1914, John Zeleny, an American scientist, reported that he was working on a mathematical model that would explain the effect of liquid droplets at the end of iron capillaries under the effect of an electric field. However, it was not until the 1930s that the scientist Anton Formhals produced the first electrospinning fibers. Over time, the technique was improved until the 1990s, when scientist Reneker used high voltage to create polymeric fibers with a diameter of less than 5 micrometers. The equipment consisted of a dispersed polymer reservoir with a pump, a high voltage source, a nozzle and a collector.


The basic principle by which electrospinning works is not new. Since the end of the 16th century, the philosopher Sir William Gilbert noticed that water droplets were affected by an electrostatic field. The drops took on the shape of a cone as they emerged from the hopper-shaped nozzle. Nowadays, a high voltage source is added to the material container to increase the electrostatic potential and polymers are usually used to make the spinning. When the drop of solution is at the tip of the hopper, due to electrostatic interactions, it will be stretched, giving the shape of a cone called a Taylor cone. If the conditions between the molecular density of the polymer and the electric potential are suitable, the stream will be stretched at a constant flow, producing a thread that reaches a piece called collector.


Through the electrospinning technique, it is possible to obtain products that can be used in different application areas such as: composites, carbon nanotubes, inorganic fibers and artificial tissues. The advantages of this technique are that it is a scalable process, the diameter of the fibers can be controlled, it is an efficient process and the nanofibers produced can be quite long. A disadvantage is the limited control that can be had on the stability of the stream.


In conclusion, the electrospinning technique is a viable option for the production of fibers, at nano scale, in laboratory or industry. It is also a technique with a potential use in different fields such as medicine, textiles, fabrics, batteries, etc. It is worth mentioning that, in recent years and due to its great scope, more resources have been allocated to research with this technique and its applications.