Researchers at the University of California, Merced have created a flexible, electrically conductive substance that may eventually increase the robustness of wearable technology, such as smartwatches.
The novel material demonstrates adaptive durability, which means that it gets stronger in response to strain or impact. The material was, strangely enough, inspired in the kitchen.
Yue (Jessica) Wang, the project's primary investigator, observes that the mixture travels easily through a mixing spoon when cornstarch and water are combined slowly. You get a different result if you take the spoon out and try to shove it back in. According to Wang, "it's like stabbing a hard surface," and the spoon does not retract.
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Wang's team wanted to create a solid, electrically conductive material with this intriguing feature.
The team had to determine the ideal mixture of conjugated polymers—long, conductive molecules with a spaghetti-like shape—in order to achieve their objective. The majority of flexible polymers shatter when struck hard, quickly, or repeatedly.
An aqueous solution containing four polymers was initially used by the researchers: shorter polyaniline molecules, spaghetti-like poly(2-acrylamido-2-methylpropanesulfonic acid), and a conductive mixture known as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).
Along the process, they made adjustments to the formula to increase adaptability and conductivity. For example, adding 10% more PEDOT:PSS increased the mixture's conductivity and adaptive durability.
The group also experimented with incorporating tiny molecules into the mixture, observing the effects of each addition on the properties of the polymers. In the end, additives with positively charged nanoparticles best enhanced adaptive functionality, reports TechSpot.
"Adding the positively charged molecules to our material made it even stronger at higher stretch rates," says Di Wu, a postdoctoral researcher in Wang's lab.
Integrated bands and rear sensors for smartwatches that might readily survive the demanding environment of a person's daily life on their wrist are examples of practical uses. Additionally, the flexible material may find use in the medical industry, where it might be integrated into wearable medical devices such as glucose monitors or cardiovascular sensors.
In order to illustrate the material's potential for usage as a prosthetic, Wu and colleagues even modified a previous version of the material that is appropriate for 3D printing and produced a facsimile of a human hand.
"There are a number of potential applications, and we're excited to see where this new, unconventional property will take us," Wang said.