Breakthrough in nanofibres

Engela Duvenage

The days of wearing clothes that only provide protection against the elements seem to be numbered - thanks to nanotechnology that is.

A breakthrough by Eugene Smit, a PhD student in Polymer Science at the Department of Chemistry and Polymer Science of Stellenbosch University, increases the likelihood that nanotechnology will provide us with multifunctional clothes that keep us warm while also acting as a warning system against air or water pollution.

Thanks to Smit's research, it is possible for the first time to produce continuous yarns from electrospun nanofibers. Smit hopes that in future this will lead to tangible applications in the fields of smart and functional textiles, as traditional methods of textile material production such as knitting could soon be used to produce textiles from continuous nanofiber yarns.

Thanks to nanotechnology, it is possible to manipulate matter on the scale of one millionth of a millimetre. On such small a scale it becomes possible to include extraordinary new properties to common materials, which can lead to new applications and technologies for everyday materials.

Smit's research was published in March in the leading journal Polymer (Vol 46/8 pp 2419-2423) and is titled Continuous yarns from electrospun fibers. He recently returned from the USA where he presented his work at the 84th World Conference of the Textile Institute - the largest organisation of its kind in the world.

His work focuses on the electrospinning technique, in which high-voltage electrical fields are applied to polymer solutions. This leads to the forming of fibres a thousand times thinner than a hair.

He uses this technique to spin nanofibres from everyday textile polymers such as acrylics (used for making shade netting), or less known polymers such as polyvinylidene difluoride used in sonar microphones.

The electrospinning technique has been known since the 1930s to produce nanofibres used in high-performance filters, wound dressings and tissue engineering scaffolds for artificial organs. Until recently, the application possibilities of these materials and the technique itself were limited because the materials made through electrospinning were usually obtained in the form of non-woven webs of randomly oriented fibres.

Smit's breakthrough lies in the fact that he has developed a technique in which continuous yarns that consist of parallel bundles of nanofibres can be produced in a continuous process.

These nanofiber yarns, in which the fibres lie parallel to one another, opens the door for application in fibre-reinforced composite materials, similar to the carbon and glass fibre materials used in sports equipment. Smit expects that the use of nanofiber yarns will lead to composite materials that are stronger yet lighter than steel.

Obtaining nanofibres as yarns is also a step closer to providing production houses with nanofibers in a manageable form to produce nanofiber textiles using traditional textile production methods such as knitting and weaving.

This research helps to make the possibility of multifunctional clothing a real possibility, and not simply an option discussed only in sci-fi movies. In future, "intelligent" and functional textiles will transform your favourite jacket into a multimedia device that allows you to connect to the Internet, measure your heart rate and blood pressure, and even guide you along on a hike in the wilderness.

Smit predicts that the implementation of nanofiber sensors in smart textiles could even enable that same jacket to warn you if the water you are drinking is polluted, or the chicken pie you are eating is past its sell-by date.

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* Smit's visit to the USA was sponsored by AMTS (Advanced Manufacturing Technology Strategy), an initiative by the South African Department of Science and Technology.

The research is supported by the National Research Foundation and the Harry Crossley Foundation. The Textile Institute's 84th world congress was held in March in Raleigh, North Carolina, in conjunction with the American National Textile Centre's 13th Annual Forum.