IN THE FUTURE, all your clothes will become smart. These intelligent clothes will outperform conventional passive garments, thanks to their miniaturized electronic circuits and sensors, which will allow you to seamlessly communicate with your phone, computer, car and other machines. The new smart clothing will make you more productive, check on your health status, and even call for help if you suffer an accident.
There will be no need to wear uncomfortable smartwatches or chest straps to monitor your heart when your comfy shirt can do a better job.
That’s the idea behind “smart clothing” developed by a Rice University lab, which employed its conductive nanotube thread to weave functionality into regular apparel.
Biomolecular engineer Matteo Pasquali reported in the American Chemical Society journal that it sewed nanotube fibres into athletic wear to monitor the heart rate and take a continual electrocardiogram (EKG).
According to the researchers, the fibres are just as conductive as metal wires but washable, comfortable, and far less likely to break when a body is in motion.
Overall, the shirt they enhanced was better at gathering data than a standard chest-strap monitor taking live measurements during experiments. When matched with commercial medical electrode monitors, the carbon nanotube shirt gave slightly better EKGs.
“The shirt has to be snug against the chest,” said Rice graduate student Lauren Taylor, lead author of the study. “In future studies, we will focus on using denser patches of carbon nanotube threads, so there’s more surface area to contact the skin.”
The researchers noted nanotube fibres are soft and flexible, and clothing that incorporates them is machine washable. The fibres can be machine-sewn into the fabric just like a standard thread. The zigzag stitching pattern allows the material to stretch without breaking them.
The fibres provided not only steady electrical contact with the wearer’s skin but also served as electrodes to connect electronics like Bluetooth transmitters to relay data to a smartphone or link to a Holter monitor stowed in a user’s pocket, Taylor said.
The fibres, each contain tens of billions of nanotubes, have been studied for use as bridges to repair damaged hearts as electrical interfaces with the brain and for automotive and aerospace applications.
At about 22 microns wide, the original nanotube filaments were too thin for a sewing machine to handle. Taylor said a rope-maker was used to create a sewable thread, essentially three bundles of seven filaments each, woven into a size roughly equivalent to a regular line.
“We worked with somebody who sells little machines designed to make ropes for model ships,” said Taylor, who at first tried to weave the thread by hand, with limited success. “He was able to make us a medium-scale device that does the same.”
Taylor said the zigzag pattern could be adjusted to account for how much a shirt or other fabric is likely to stretch. Taylor said the team is working with Dr Mehdi Razavi and his colleagues at the Texas Heart Institute to figure out how to maximize contact with the skin.
Fibres woven into fabric can also be used to embed antennas or LEDs, according to the researchers. Minor modifications to the fibres’ geometry and associated electronics could eventually allow clothing to monitor vital signs, force exertion or respiratory rate.
Taylor noted other potential uses could include human-machine interfaces for automobiles or soft robotics, health monitors and ballistic protection in military uniforms. “We demonstrated with a collaborator a few years ago that carbon nanotube fibres are better at dissipating energy on a per-weight basis than Kevlar, and that was without some of the gains that we’ve had since in tensile strength,” she said.
“We see that, after two decades of development in labs worldwide, this material works in more and more applications,” Pasquali said. “Because of the combination of good contact with the skin, and nanotube threads that are a natural component for wearables.”
He said the wearable market, although relatively small, could be an entry point for a new generation of sustainable materials that can be derived from hydrocarbons via direct splitting. This process also produces clean hydrogen. The development of such materials is a focus of the Carbon Hub.
“We’re in the same situation as solar cells were a few decades ago,” Pasquali said. “We need application leaders that can provide a pull for scaling up production and increasing efficiency.”
