Long-lasting hats, jumpers and watch straps that function as smart devices can be made thanks to a cheap and reliable method of creating conductive fibre that can be woven into fabric
By Matthew Sparkes
31 January 2024
This hat might look ordinary, but it can sense when traffic lights change colour
Zhixun Wang
Flexible and wear-resistant strands of conductive fibre have been used to make smart clothes with embedded computers and sensors, such as hats that can sense traffic light changes.
Previous efforts to create fibres with a hardwearing coating and a conductive core have run into problems. Materials cooling and contracting at different rates during manufacture or being twisted or washed once in a final product often cause tiny stress cracks, stopping a smart device from working.
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Now, Lei Wei at Nanyang Technological University, Singapore, and his colleagues have made conductive materials that cool and contract in a similar way to the aluminosilicate glass used in smartphone screens, so that stress cracks don’t appear. The material borrows techniques for making fibre-optic cable, and Wei says the process is both cheap and “industry ready”.
The technique involves placing a semiconductor wire made of silicon or germanium into molten glass at temperatures of about 1000°C and pulling it into fine strands. The glass is later etched away with hydrofluoric acid and replaced with a polymer coating, which allows for a more flexible material. The fibres can stretch for up to 10 kilometres.
Small amounts of this fibre are then woven into a fabric using standard weaving machines and normal cotton. Wei says cotton is needed to make the clothes comfortable because the new material alone feels like “fishing line” against the skin.