By Isobel Williams via SWNS
A new stretchy electronic material that becomes tougher when you hit it was inspired by corn starch.
It could be the future of health monitors, smartwatches, and prosthetics, say scientists.
New research has unveiled a soft, flexible material with “adaptive durability,” meaning it gets stronger when hit or stretched.
The team say that their invention was inspired by the simple cooking ingredient.
Assistant Professor Yue Wang, of the University of California, said: “When I stir cornstarch and water slowly, the spoon moves easily. But if I lift the spoon out and then stab the mixture, the spoon doesn’t go back in. It’s like stabbing a hard surface.”
The researchers were inspired by this culinary mystery to mimic this property in a solid conductive material.
Initially, the researchers made a solution of four polymers. They then spread a thin layer of the mixture and dried it to make a film.
In a test of this new material, they found that rather than breaking apart from very rapid impacts, it deformed or stretched out.
In fact, the faster the impact, the more stretchy and tough the film became.
The authors describe that this is because the four polymers, two with positive charges and two with negative charges, tangle up like a big bowl of spaghetti and meatballs.
Dr. Di Wu, a postdoctoral researcher in Wang’s lab, explained: “Because the positively charged molecules don’t like water, they aggregate into meatball-like microstructures.”
The team next investigated how adding small molecules could create a material that was even tougher when stretched or dropped quickly.
They found that the positively charged nanoparticles made of 1,3-propanediamine were the best additive.
Dr. Wu says that the additive weakened the interactions of the polymers that form the “meatballs,” making them easier to push apart and deform when hit and strengthening the tightly entangled “spaghetti strings.”
He added: “Adding the positively charged molecules to our material made it even stronger at higher stretch rates.”
The team say that the possibilities for their discovery include soft wearables, such as integrated bands and backside sensors for smartwatches, and flexible electronics for health monitoring, such as cardiovascular sensors or continuous glucose monitors.
Additionally, the team formulated a previous version of the adaptive material for 3D printing and produced a replica of a team member’s hand, demonstrating the potential incorporation into personalized electronic prosthetics.
Dr. Wang added: “There are a number of potential applications, and we’re excited to see where this new, unconventional property will take us.”
The findings are due to be presented at the Spring meeting of the American Chemical Society (ACS) in New Orleans.
