Scientists have developed a stretchable and waterproof ‘fabric’ that turns energy generated from body movements into electrical energy. As reported in the scientific journal Advanced Materials in April as a proof-of-concept experiment, the Scientists at Nanyang Technological University, Singapore (NTU Singapore) team showed that tapping on a 3cm by 4cm piece of the new fabric generated enough electrical energy to light up 100 LEDs.
A crucial component in the fabric is a polymer. When pressed or squeezed, that converts mechanical stress into electrical energy. In order to keep it strong, flexible, and waterproof, it is made with stretchable spandex as a base layer and integrated with a rubber-like material.
How is the ‘fabric’?
Washing, folding, and crumpling the fabric did not cause any performance degradation, and it could maintain stable electrical output for up to five months, demonstrating its potential for use as a smart textile and wearable power source.
Materials scientist and NTU Associate Provost (Graduate Education) Professor Lee Pooi See, who led the study, said, “There have been many attempts to develop fabric or garments that can harvest energy from movement, but a big challenge has been to develop something that does not degrade in function after being washed, and at the same time retains excellent electrical output. In our study, we demonstrated that our prototype continues to function well after washing and crumpling. We think it could be woven into t-shirts or integrated into soles of shoes to collect energy from the body’s smallest movements, piping electricity to mobile devices”.
The fabric as an energy-harvesting device
The electricity-generating fabric is an energy harvesting device that turns vibrations produced from the smallest body movements in everyday life into electricity.
The prototype fabric produces electricity in two ways: when it is pressed or squashed (piezoelectricity), and when it comes into contact or is in friction with other materials, such as skin or rubber gloves (triboelectric effect).
How did the scientists fabricate?
To fabricate the prototype, the scientists first made a stretchable electrode by screen-printing an ‘ink’ comprising silver and styrene-ethylene-butylene-styrene (SEBS), a rubber-like material found in teethers and handlebar grips to make it more stretchable and waterproof.
This stretchable electrode is then attached to a piece of nanofibre fabric that is made up of two main components: poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HPF), a polymer that produces an electrical charge when compressed, bent, or stretched; and lead-free perovskites, a promising material in the field of solar cells and LEDs.
NTU PhD student Jiang Feng, who is part of the research team, explained, “Embedding perovskites in PVDF-HPF increases the prototype’s electrical output. In our study, we opted for lead-free perovskites as a more environmentally friendly option. While perovskites are brittle by nature, integrating them into PVDF-HPF gives the perovskites exceptional mechanical durability and flexibility. The PVDF-HPF also acts an extra layer of protection to the perovskites, adding to its mechanical property and stability”.
The result is a prototype fabric that generates 2.34 watts per square meter of electricity -enough to power small electronic devices, such as LEDs and commercial capacitors.
Recommended: Changes in 2022 fashion world
Is the concept proved?
To demonstrate how their prototype fabric could work, the NTU scientists showed how a hand tapping on a 3cm by 4cm piece of the fabric continuously could light up 100 LEDs, or charge various capacitors, which are devices that store electrical energy and are found in devices like mobile phones.
The fabric showed good durability and stability, and its electrical properties did not deteriorate following washing, folding, and crumpling. It also continued to produce a continuous stable electrical output up to five months.
The team also showed that their fabric could harness energy from a range of human movements by attaching it to the arm, leg, hand, and elbow, as well as to the insoles of shoes, and did so without impacting on the movements.
“Despite improved battery capacity and reduced power demand, power sources for wearable devices still require frequent battery replacements. Our results show that our energy harvesting prototype fabric can harness vibration energy from a human to potentially extend the lifetime of a battery or even to build self-powered systems. To our knowledge, this is the first hybrid perovskite-based energy device that is stable, stretchable, breathable, waterproof, and at the same time capable of delivering outstanding electrical output performance”, Prof Lee said.
This fabric-based energy harvesting prototype builds on the NTU team’s body of work that looks at how energy generated in the environment could be scavenged. For instance, the team recently developed a type of film that could potentially be mounted on roofs or walls to harness the energy produced from wind or raindrops falling onto the film.
What will be its influence in the world of fashion?
Experts say the development of such a fabric could have a number of influences and implications in the world of fashion and lifestyles.
For example, the fabric could help people to extend their phones’ battery life by collecting energy from their movements. This could also be applied in wearable technologies that can harvest energy from human movements, such as shoes, hand-held devices (smartwatches), or other technology that can be integrated into garments -in this case t-shirts or footwear- for long-term charging of smartphones and other devices.
In addition to this, the fabric could be used in wearable technologies that require self-powered systems, such as health monitoring devices, or devices that can track a person’s movements.
The team is now looking at how the same fabric could be adapted to harvest different forms of energy.
This research has added a new dimension to the world of science. With the advancement in technology, scientists are looking beyond the human-to-human contact, seeking to produce electricity without direct human contact. Obviously, in future, humans could not only be independent of electrical power. but will also be self-sufficient.
But then as we all know that in this world of science and technology research and development is a continuous process. What is very good today can be improved upon tomorrow to produce something better.
Also Read: Role of fashion in building your personality