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Electrospinning - Nanofibers and Nanoscaffolds
Nanofibers Mimic Nature
The Art Of Electrospinning
Electrospinning Webs Of Nanofibers
For a moment, I had a short term of employment at a local Fiberglass product company. The fiberglass company specializes in producing products that rely on the matrix of fiber reinforced polymer. Everyday we encounter things that are made from or improved through the use of fiberglass: car parts, surfboards, industrial pieces. It turned out that I was not too enthusiastic about working on an assembly line to produce consumer products while taking a daily dose of epoxy and fiberglass shards to the skin. The management realized this as well and the job did not last too long. But, I did learn, first hand, about the incredible versatility and strength to be found in fine fibers of glass. Since the 1900s (patented by J. F. Cooley) researchers have found a similar usefulness in a phenomena known as electrospinning that can be used to draw extremely fine fibers from an electrically charged liquid polymer. In the 1990s the process of electrospinning was improved to the point that an electrospinning unit that can produce invisible fibers of nanometer-scale diameters can be purchased at a relatively reasonable price.
The components that make up an electrospinning unit are a syringe pump, a spinneret / nozzle, and a rotating or plate collector and they are all easy to buy. Electrospinning relies on a voltage being applied to a liquid droplet until electrostatic repulsion stretches the droplet until a point of eruption where a stream of the liquid is emitted onto the electrospinning collector. Early electrospinning machines were able to produce microfibers, but it was not until the mathematical work of Sir Geoffrey Ingram Taylor that the complete mathematical description came to be. His mathematical model of the shape of the eruption cone gave rise to nomenclature in honor of him. It is known as the Taylor cone. A wide variety of electrospinning polymers can be used to produce the output fibers. These may include polyethylene glycol (Carbowax), DNA, the biopolymer polylactic acid, PAA and more. Other resin, nylon, cellulose and organics can be used as well. The variety of electrospinning compatible polymers gives rise to many applications.
Electrospinning and electrospun nanofibers can be used to create improved textile materials with an increased inherent protection against moisture and other elements. Agricultural workers or firefighters might be a few candidates to sport electrospun nanofibrous material to assist in their daily duties. Tests have been done on polyurethane electrospun fiber web layered textile material that showed that such a solution is a more protective barrier against pesticides of a varying viscosity. Other hazardous and toxic environments may also benefit from electrospinning. Another important area of application is filtration. Water treatment nanotechnology is a science all its own with aims to improve groundwater and wastewater filtering methods through nanoscale innovations. Electrospinning can provide better water filtration membranes that are more resistant to biofouling by bacteria which would otherwise contaminate drinking water. Nanobiocides can also be incorporated into the electrospun fiber mesh in order to induce a higher antimicrobial properties. Nanofiltration membranes are combining with reverse osmosis methods to improve water quality. This is an area to look into if one wants to have the highest quality drinking water at home and not have to worry about fluoride or other government additions. One more increasingly promising medical application of electrospinning is in the production of nanoscaffolds. The polymer fibers can be spun into a porous structure through which cells and tissue can cling to while growing. Once the growth has been achieved the nanoscaffold practically dissolves into the body. Recent breakthroughs have led to 3d nanoscaffolds that are like a cotton ball and can better receive the growth material. The regrowth of burned skin and bone has been studied heavily using this method.
The spider weaves his fractal masterpiece of a web without knowing the science behind the process he performs, but an improved understanding of polymers and their various electrospinning applications can take humans into a new web of wonder.