Tannic acid may be the key to next-gen wearable tech.
A team of scientists from the University of Manchester have made a wearable technology discovery involving tannic acid that could lead to the development of more durable and flexible wearable devices. The researchers extracted tannic acid from red wine, coffee and black tea for their experiment.
Adding tannins to the technology improved mechanical properties of certain materials, increasing lifespan.
Through their wearable technology discovery, the scientists found that by adding tannic acid extracted from red wind, coffee or black tea, this improved mechanical properties of materials like cotton, to develop wearable sensors for rehabilitation monitoring, significantly boosting the devices’ lifespan.
With the addition of the tannins, the team of scientists have developed wearable devices such as artificial hands and capacitive breath sensors for extreme conditions by enhancing the durability of flexible sensors. This could revolutionize the wearable tech industry because previously the tech has been prone to fail after repeated folding and bending, which can interrupt the conductivity of these devices due to tiny microcracks. Improving the durability of such devices could make it possible for longer-lasting integrated technology.
“We are using this method to develop new flexible, breathable, wearable devices. The main research objective of our group is to develop comfortable wearable devices for flexible human-machine interface,” said Dr. Xuqing Liu who led the research team, Phys.org reports.
The wearable technology discovery could drastically improve the durability, comfort and performance of devices.
Dr. Xuqing Liu noted that traditional conductive material has trouble bonding to the fibers and this can result in low conductivity. However, adding tannic acid provides good adhesion because the acid can firmly absorb the material on the service of the fiber. It’s this same reason why red wine, coffee or black tea stains on clothes are hard to remove. This good adhesion is precisely what is needed for durable wearable, conductive devices.
In their new research, which was published in the journal Small, the scientists demonstrated that without the layer of tannic acid, the conductivity is several hundred or even thousands of times less than conventional conductive material samples. The reason is the conductive coating becomes easily detached from the textile surface from repeated flexing and bending.
In their tannic acid experiment, the team used both commercially available tannins and also immersed the fabric directly in red wine, black coffee and black tea and saw the same improved results in both cases.
In addition to drastically improving durability and performance, the wearable technology discovery could also see a decrease in price for this technology and improve its comfort and robustness. This would 
allow for comfortable fabrics like cotton to replace nylon and for circuits to be printed directly onto the surface of clothing to create a comfortable, flexible circuit board.
