This high-tech yarn: just stretch or twist it to generate electricity

Have you ever imagined that there is a kind of yarn that can be generated by stretching or twisting? Now, a yarn called Twistron can generate electricity. Scientists assume that it can be placed in waves or temperature fluctuations to collect energy and convert it into electricity. The power generation yarns were developed by scientists from the University of Texas at Dallas and Hanyang University in Korea. On August 25th, relevant research results were published in the journal Science, and the author of the communication was Professor Ray Baughman of the Nanotechnology Institute at the University of Texas at Dallas.

Twistron yarn

“Twistron” is essentially a capacitor that does not require an external power source. It is spun from a number of carbon nanotubes. A single carbon nanotube is a hollow cylinder with a diameter of 10,000 times the diameter of a human hair. In order to improve the elasticity of the yarn, the researchers continuously improve the twist of the yarn so that the yarn assumes a spring-like spiral structure.

To generate electricity, "Twistron" requires the help of electrolytes in addition to its unique construction and must be soaked or coated with an ionically conductive material such as salt water. Subsequently, the ions in these electrolytes are automatically inserted into the yarns. When the yarns are stretched or twisted, the charges on the yarns are close to each other and the voltage is increased to generate electrical energy.

In the lab, the researchers tested a Twistron yarn weighing less than the housefly. As a result, it was found that the electric energy generated by the yarn can light up a small LED each time it is stretched. According to reports, curled twistron yarns can produce 250 watts per kilogram (of yarn weight) of peak electrical power when stretched at 30 times per second.

Interestingly, Ray Bowman once used polymer artificial muscle made of polyethylene and nylon three years ago and was able to lift 100 times the weight of natural muscles of the same size. The polymer muscles contracted and elongated when heated and frozen. So the researchers connected a Twistron yarn to it and tested whether the Twistron could collect waste heat from the environment. The experimental results show that Twistron can indeed convert the mechanical energy of artificial muscle into electrical energy.

The Bowman team is very optimistic about the application scenario of Twistron. It may be able to power electronic textiles, or it can be placed in seawater to collect the mechanical force of the waves as electrical energy.

In the lab, the researchers sew Twistron into the top, and tests have found that as the human body breathes normally, the yarn stretches and produces electrical signals as the chest rises and falls.

"Electronic textiles have very good business prospects, but how can we power it?" Bowman said. “Receiving electrical energy from the movement of the human body is a strategy to solve the battery demand. Compared with other woven fabrics reported in the literature, the unit weight of twistron yarn can provide more than a hundred times more than their electric power.”

Experiments in seawater also demonstrate the potential of Twistron applications. In the sea on the east coast of South Korea, researchers tested the feasibility of the power generated by the Twistron in seawater. They connected a 10 cm long, 1 mg weight yarn between a balloon and a sinker resting on the seabed. When there is a wave, the balloon will rise and stretch the yarn up to 25% of the elongation.

Bowman believes that the Twistron yarn can get huge energy from the waves, he said, based on the average output power achieved so far, only 31 milligrams of Twistron yarn can be used to provide transmission every 10 seconds for a radius of 100 meters. Energy required for kilobytes of data packets. However, if it is to be put into use, the production cost of Twistron still needs to be reduced.