Scientists don thinking caps in wearable tech breakthrough
Building semiconductors into fabrics often hits a snag, which a new fiber pulling technique seeks to avoid
Smart clothing is a go-to item on the hype-cycle bandwagon, which never seems to arrive. Yet for anyone wanting to play Doom on their knitwear, a glimmer of hope was reported by scientists this week.
A group of researchers based in Singapore report some success in developing tiny semiconductor components that can be fed into a fiber-pulling machine, resulting in continuous high-performance flexible fibers that can sense, communicate, and interact with each other.
The latest development overcomes existing fabrication methods and can produce threads with fractured, defective semiconductor cores, according to an accompanying review.
Nanyang Technological University post-doctoral researcher Zhixun Wang and his team figured out that stresses form on woven semiconductors where the core solidifies and, in a separate, subsequent phase, when the fiber is cooled. The stresses resulted from the different melting points and thermal expansion rates of the chosen materials, according to a paper published in Nature.
“The authors showed that both problems could be alleviated by choosing the right combination of materials: silicon cores worked well with cladding made from ultra-tough silica glass, whereas germanium cores performed better when clad in aluminosilicate glass,” said Virginia Tech researchers Xiaoting Jia and Alex Parrott in an accompanying article.
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The researchers developed a way of enveloping semiconductor materials in fibers by inserting them inside a glass tube where both materials are heated until they are soft enough to be pulled into a thin strand, which is then cooled. After the glass is removed by acid, the wire is threaded into a polymer tube along with metal wires. After another round of heating, the material can be pulled into a thread hundreds of meters long. It is capable of detecting and processing signals, the researchers claim.
To demonstrate their development, the team produced a functional beanie hat to show an outdoor application of the technology in assisting the visually impaired. The interface board was placed inside the hat, while the signal received from the beanie could be processed by a mobile phone application.
From the paper, figure d is "the functional beanie used in the demo. The interface board was placed inside the beanie tip. Below he fig, the signal received by the beanie is visualized in a mobile application. Figure e is a "functional sweater for indoor Li-Fi communication system. Beneath it is a block diagram of receiving data via the functional sweater, and a photo of the building (the Learning Hub at Nanyang Technological University) that was sent and received via the sweater. Figure f is a watchband measuring heart pulses via photoplethysmography, with the optoelectronic fibers woven into the watchband. (Click to enlarge)
“Our work has shown that optoelectronic fibers, fabrics and functional apparel can be achieved using the semiconductor fibers, providing a promising pathway to achieve high-performance functional fibers and fabrics, as semiconductors are the critical components that primarily govern the devices’ performance. Our findings may bring functional fibers one step further towards unprecedented sensing, actuating, energy converting and computing capabilities,” the researchers said.
Xiaoting Jia and Alex Parrott added: “Because the wires embedded in Wang and colleagues’ fibers are easily connected to existing computer hardware, this technology could prove useful in efforts to develop integrated human–machine systems. The work therefore allows us to imagine a generation of smart fibers and fabrics that enable individuals to engage seamlessly with their surroundings – and make their everyday experiences fully immersive.”
One day. Maybe. ®