From sweat-sensing wristbands toelectrode-embedded workout suits, new innovations in smart clothingare coming thick and fast. Now, Ohio State Universityresearchers have made another big breakthrough, managing to createembroidered circuits using metallic thread that's just 0.1 mm thick.By embedding different patterns, the tech could be used to createeverything from a t-shirt that boosts your cellphone signal, to a hatthat tracks brain activity.
Embroidery is not likely something thatyou'd associate with cutting edge technology, but a new breed offunctional textiles, known as "e-textiles" are set to challenge thatperception. The concept makes use ofsewing machines capable of embroidering thread into fabricautomatically based on a pattern sent to it from a computer. But rather than traditional thread, fine metal wires are used.
The Ohio State researchers have beenworking to refine the process for a couple of years, and have madesignificant progress in that time. At the start of the project, theteam was working with silver-coated polymer thread measuring about0.5 mm (0.02 in) across and made up of 600 fine filaments twistedtogether.
They've since moved to a much thinneralternative that's only made up of seven filaments, each with acopper center and enameled with pure silver. The new thread isthinner, but thanks to its materials, maintains high conductivity.Because it's so thin, at just 0.1 mm, the resulting fabricfeels just the same as if traditional thread had been used, with noneof the rigidity you might initially expect.
So, how does that embedded metal wiringtranslate to functional use? Well, it's all in the shape. Dependingon the pattern that's embroidered, it's possible to create manydifferent useful products. For example, a broadband antenna can becreated by embedding numerous interlocking geometric shapes thattogether form a circular pattern measuring a few inches across. Thewiring required to produce that antenna only costs around 30 cents,and the embroidery process reportedly takes just 15 minutes to complete.
The researchers have also used the embroidery technique to embedded an RFID chip in rubber – a part of a project undertaken in partnership with a tire manufacturer.
Looking forward, the team intends tocontinue its work on smart clothing, and there are plans to licensethe technology out, meaning that these sci-fi-sounding products might just become a purchasable reality somewhere down the line.
"A revolution is happening in thetextile industry," said director of the Ohio State Universitylaboratory John Volakis. "We believe that functional textiles arean enabling technology for communications and sensing – and one dayeven medical applications like imaging and monitoring."
The research has been published online in the journal IEEE Antennas and Wireless Propagation Letters.
Source: Ohio State University
