Smart clothing has been developed that employs conductive nanotube thread to weave functionality into regular apparel. The fibers were sewn into athletic wear to monitor the heart rate and take a continual electrocardiogram (EKG) of the wearer. The fibers are just as conductive as metal wires but washable, comfortable, and far less likely to break when a body is in motion.
The shirt was better at gathering data than a standard cheststrap monitor taking live measurements during experiments. When matched with commercial medical electrode monitors, the carbon nanotube shirt gave slightly better EKGs. The shirt must be snug against the chest; future studies will investigate denser patches of carbon nanotube threads so there is more surface area to contact the skin.
The nanotube fibers are soft and flexible and clothing that incorporates them is machine washable. The fibers can be machine-sewn into fabric just like standard thread. The zigzag stitching pattern allows the fabric to stretch without breaking them.
The fibers 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 connect to a Holter monitor that can be stowed in a user’s pocket. The original nanotube filaments, at about 22 microns wide, were too thin for a sewing machine to handle. A rope-maker was used to create a sewable thread — essentially three bundles of seven filaments each, woven into a size roughly equivalent to regular thread.
The zigzag pattern can be adjusted to account for how much a shirt or other fabric is likely to stretch. Fibers woven into fabric can also be used to embed antennas or LEDs. Minor modifications to the fibers’ geometry and associated electronics could eventually allow clothing to monitor vital signs, force exertion, or respiratory rate. Other potential uses could include human-machine interfaces for automobiles or soft robotics or as antennas, health monitors, and ballistic protection in military uniforms.