January 25, 2020 by Luke James
A new stretchy, self-mending material is said to have the ability to utilize body heat to produce electricity, which in turn can be used to power wearable devices.
Sensors, devices, and medical solutions that are worn on the skin or as implants have an endless variety of potential applications. From tracking your run to monitoring valuable signs of human health including heart rate, blood pressure, and brain activity, wearable and implantable technology is constantly evolving.
Now, according to a team of researchers at KAUST in Saudi Arabia, led by Derya Baran and Seyoung Kee, a self-healing thermoelectric material has been developed with properties that could mean that it is eventually used in wearable electronic devices to enable them to remain perpetually charged and better withstand the rigors of daily use.
A schematic illustration of the mechanical and thermoelectrical self-healing process of the composite film.
Thermoelectric materials use temperature gradients to generate electricity. Using heat from the human body, they have the potential to power wearable technologies in perpetuity, eliminating the need for recharging and, possibly, batteries altogether. However, current thermoelectric materials lack the strength, flexibility, and resilience to avoid being damaged by normal daily activities.
However, the team at KAUST in Saudi Arabia have managed to blend the highly conductive thermoelectric polymer, PETOT:PSS, with dimethyl sulfoxide, an organic compound that boosts the performance of PETOT:PSS, and Triton X-100, a sticky gel-like substance that facilitates hydrogen bonding with PETOT:PSS.
Using a 3D printer to deposit this mixture of dimethyl sulfoxide and Triton X-100, the researchers tested the thermoelectric performance of their thermoelectric films under stress.
The self-healing properties of the films were tested by cutting them in half while they powered an LED light. “Amazingly, the light did not go out during or after cutting,” said Kee in the team’s research paper, published in Advanced Functional Materials. “I repeated the cut ten times, but it continued to self-heal in less than one second and retained 85 per cent of its power output.” Even when the film was stretched to three times its original size, it was still able to provide a stable power supply.
This alone represented a major leap forward in thermoelectric materials. “Wearable electronics are under continuous strain, and their power supply is prone to breaking,” said Kee. “Our material can provide constant and reliable power because it can deform, stretch, and most importantly, heal itself…”
The research team hope to find materials with even better thermoelectric properties in the future so that they can generate greater power. It will be interesting to see how the Saudi research team will develop this technology as it clearly holds a lot of potential.
If thermoelectric materials can be developed further and utilized to their full potential, possibly eliminating batteries in wearables altogether, use cases could be found in everything from smartwatches and medical implants to smart clothing and more, especially since the thermoelectric material is capable of monitoring vital signs.
