Professors from the Department of Aerospace Engineering and Fluid Mechanics of the School of Engineering of the University of Seville have developed a method for mass production of microfibers -very thin fibers-, which have numerous applications, for example, they are used to manufacture masks and PPEs, regenerate tissues, for energy generation and storage systems or for the so-called "smart fabrics". The discovery is intended to revolutionize conventional methods, since the technology used is more efficient and would multiply production a thousandfold.
The relevance of this work, published by the Royal Society of Chemistry, lies in the industrial mass production of nanofibers, made of a polymer called polyvinyl alcohol (PVA). These microfibers have a diameter of less than 1 micron, i.e., they can be as thin as the coronavirus, which is one hundred times thinner than a human hair (100 microns) or eight times smaller than a red blood cell (8 microns).
Simple but robust technology
The study aimed to develop a simple but robust technology to produce micro- and nanofibers using pneumatic injectors that use a liquid spraying process, similar to that generated by terrace sprinklers.
Professors Luis Modesto López and Alfonso Gańán Calvo, together with student Jesús Olmedo Pradas, present the article on this new technology. Modesto López explains that "the research began with sputtering trials in which the aim was to produce microdroplets. However, instead, we obtained elongated structures that we call ligaments. We realized that ligaments were formed by using highly viscous liquids with some viscoelasticity. We turned to a heat source, sprayed, and the heat allowed the ligaments to dry quickly, resulting in the formation of microfibers in a matter of seconds."
The experts claim that this technology is more energy efficient than current methods, as it does not rely on an external energy source to fragment the liquid, but "harnesses the mechanical energy contained in the air stream to generate new surface area, i.e., a multiplicity of thinner ligaments."
This project opens a new line of research related to the fabrication of composite fibers consisting of two or more polymeric materials. The study has been financed with funds from the Andalusian Plan for Research, Development and Innovation (PAIDI 2020) and European FEDER funds.