Researchers at Rice University managed to create flexible carbon nanotube fibers that can be incorporated into clothing to function as wearable health monitors. The new thread is highly conductive, but it is washable and strong, allowing it to function as an unobtrusive component of clothing. So far, the researchers have incorporated the fibers into a sports shirt that can monitor heart rate and obtain a continual electrocardiogram. The technology could act as a replacement for uncomfortable or impractical wearables, such as chest straps.
Wearables promise unobtrusive health monitoring, but how unobtrusive is a chest strap? This latest research promises smart clothes, which can monitor your health truly unobtrusively as you wear them. The technology is based on highly conductive carbon nanotubes that have been woven together to form a strong and flexible thread that can be machine washed, allowing for long-term incorporation into fabrics.
The new thread is robust and flexible enough to be machine sewn into fabrics, allowing the researchers to position it where they want, including where it makes maximal skin contact or in an area of interest, such as the chest for heart monitoring. The Rice University team incorporate the threads using zig-zag shapes to let the material to elongate without breaking, as the fabric flexes and stretches during activity.
“The shirt has to be snug against the chest,” said Lauren Taylor, a researcher involved in the study, in a Rice announcement. “In future studies, we will focus on using denser patches of carbon nanotube threads so there’s more surface area to contact the skin.”
As well as functioning as sensors that obtain data from a wearer’s skin, the fibers act as electrodes that can be attached to a device, such as a Bluetooth transmitter, allowing for wireless data transfer to a smartphone.
The nanotubes themselves are tiny, at 22 microns in diameter, and so the researchers had to develop specialized equipment to bundle them together into a robust thread. “We worked with somebody who sells little machines designed to make ropes for model ships,” said Taylor. “He was able to make us a medium-scale device that does the same.”
The Rice researchers hope that the threads could be useful in a wide array of wearables. “We see that, after two decades of development in labs worldwide, this material works in more and more applications,” said Matteo Pasquali, another of the developers of the new thread. “Because of the combination of conductivity, good contact with the skin, biocompatibility and softness, carbon nanotube threads are a natural component for wearables.”
See a video about the technology below.
Study in Nano Letters: Washable, Sewable, All-Carbon Electrodes and Signal Wires for Electronic Clothing