There is no denying it, a lot of innovation is taking place in the field of smart textiles. That is why we were super excited to read, in an issue of Science, that a research team,led by scientists at The University of Texas at Dallas and Hanyang University in Seoul, South Korea, have developed a new form of yarnology, called Twistron, that generates electricity when stretched or twisted.
Sewing Yarnology Into Dumb Textiles
Described as “twistron”, the yarn is capable of harvesting energy from the motion of ocean waves or from temperature fluctuations. It works by sewing the yarns into something like a shirt, the yarns then serve as a self-powered breathing monitor, creating a new way of fabricating smart textiles. On their invention, Dr. Carter Haines associate research professor in the Alan G. MacDiarmid NanoTech Institute at UT Dallas said, “The easiest way to think of twistron harvesters is, you have a piece of yarn, you stretch it, and out comes electricity.”
According to the University of Texas at Dallas news centre article, No Batteries Required: Energy-Harvesting Yarns Generate Electricity, the yarns are constructed from carbon nanotubes, that are hollow cylinders of carbon 10,000 times smaller in diameter than a strand of human hair. They article explains, “The researchers first twist-spun the nanotubes into high-strength, lightweight yarns. To make the yarns highly elastic, they introduced so much twist that the yarns coiled like an over-twisted rubber band. In order to generate electricity, the yarns must be either submerged in or coated with an ionically conducting material, or electrolyte, which can be as simple as a mixture of ordinary table salt and water.”
When it comes to the nitty gritty, Dr. Na Li, a research scientist at the NanoTech Institute and co-lead author of the study explains, “Fundamentally, these yarns are supercapacitors. In a normal capacitor, you use energy — like from a battery — to add charges to the capacitor. But in our case, when you insert the carbon nanotube yarn into an electrolyte bath, the yarns are charged by the electrolyte itself. No external battery, or voltage, is needed.”
“No other reported harvester provides such high electrical power or energy output per cycle as ours”
Dr. Carter Haines adds, “When a harvester yarn is twisted or stretched, the volume of the carbon nanotube yarn decreases, bringing the electric charges on the yarn closer together and increasing their energy”. This increases the voltage associated with the charge stored in the yarn, enabling the harvesting of electricity. Dr. Ray Baughman pipes in, “Although numerous alternative harvesters have been investigated for many decades, no other reported harvester provides such high electrical power or energy output per cycle as ours for stretching rates between a few cycles per second and 600 cycles per second.”
Weighing less than a housefly, the Twistron yarn could power a small LED, that will light up each time the yarn is stretched. Connected to a polymer artificial muscle that contracts and expands when heated and cooled, the ear harvests the mechanical energy generated by the polymer muscle to electrical energy. On their amazing achievements, Li shared, “There is a lot of interest in using waste energy to power the Internet of Things, such as arrays of distributed sensors. Twistron technology might be exploited for such applications where changing batteries is impractical.”
One step closer, The University of Texas at Dallas and Hanyang University in South Korea understand that although they have achieved a lot, there still have a ways to go before the words Twistron Yarn become the norm. With their patented technology leading the way, we can look forward to a future were our clothes might become as powerful enough to keep us connected.