Electrospun Nanofibers Take Technical Textiles to a New Level

"Smart" devices, appliances, glasses, watches, clothing, and numerous other items have flooded the market in recent years. The global market for the smart clothing sector alone is expected to reach $2 billion by the end of this year. One of the reasons for the technological strides is the advances in technical textiles. Smart fabrics must be able to conduct electricity, as well as be flexible, breathable, and comfortable for the wearer. Those specs have proven difficult until recently. A group of international researchers tested the use of polymer nanofiber composite nonwovens that were produced through the process of electrospinning. Their research yielded a bendable and breathable fabric with metal-like electrical conductivity. While electrospinning has been used to manufacture nonwovens for many years, its application to smart clothing is revolutionizing this new technology.

What are Nanofibers?

As the name implies, nanofibers are really tiny fibers. The field of nanotechnology encompasses any fiber with a diameter of about 100 nanometers. How small is that? Consider this. The human hair has an average diameter of 100 microns or 100,000 nanometers. Fine cotton has an average diameter of 20 microns or 20,000 nanometers. Both of these are a thousand times larger than fibers produced by nanotechnology, which has a diameter of only 100 nanometers. Nanofibers are so tiny it is impossible to handle them in their singular form. They are often produced as accumulated webs called nanofiber webs through the electrospinning process. Here are five key advantages of nanofibers produced through electrospinning.

• A high surface area to volume ratio makes nanofibers ideal for sensors. 
• Versatility makes nanofibers functional a wide variety of polymers and materials can be used to form nanofibers. The perfect blend can be created prior to spinning, depending on its intended function. 
• The fiber deposition easily works with a variety of substrates Depending on their use, electrospun fibers can be deposited on metal, glass, microfibrous mat, water, or on a variety of other substrates. 

How Does Electro-spinning Work?

Special techniques, such as electro-spinning are required to produced nanofibers. The nanofiber webs mentioned above are produced in a spunbonding or meltblowing process. During the process, a polymer solution or melt is exposed to high electrical field forces, making them elongate and form a jet of solvent and polymer. The solvent eventually evaporates, while the polymer flow whips and spins, forming a nanofiber web. This web is being successfully used both as a substrate and as is for wound dressing, drug delivery, and other medical applications. 

In the case of the smart fabric developed by researchers mentioned at the outset, electrospinning was used to combine polymer fibers with tiny silver wires in a liquid. That mixture was filtered, dried, and heated to produce a smart textile that can conduct electricity and is comfortable for the wearer. 

Watch our video series about biomedical innovation.

Conclusion

A report from Cientifica calls smart textiles a "fourth industrial revolution" that will be worth more than $130 billion by 2025. Specifically, researchers predict the value of nanomaterials will sharply increase due to wearables and the additional functionality that results from using these tiny fibers. Instead of a sensor attached to a garment, the next generation will produce wearables that are the sensor itself.

Sportswear and the medical industries are poised to benefit the most from these new technologies. Think beyond simple shirts that track motion and heart rate metrics in real time improvements to form and prevention of injury with running shorts that monitor cadence, ground contact time, pelvic rotation, and stride length, while providing feedback through headphones. Prevent the instances of SIDS in newborns with a smart sock that uses the same pulse monitoring technology used in hospitals to track your infant's heart rate and ensure their breathing hasn't stopped. The opportunities for wearables are infinite with the help of technical textiles.