Scientists at the University of Rochester have created a new type of ‘super polymer’ that could prove an extremely useful technology in the healthcare and clothing industries.
The material, which can lift 1,000 times its own mass, was developed by a research team led by Chemical Engineering Professor Mitch Anthamatten. In a press release the university explained that the material can be programmed to retain a temporary shape until is triggered – typically by heat – to return to its original shape.
“Tuning the trigger temperature is only one part of the story,” said Anthamatten. “We also engineered these materials to store large amount of elastic energy, enabling them to perform more mechanical work during their shape recovery.”
Potential uses of the technology include medical sutures, artificial skin, body-heat assisted medical dispensers and self-fitting apparel, according to the university.
The professor, who worked on the project with graduate student Yuan Meng, described the polymer as like a rubber band that can lock itself into a new shape when stretched. “A simple touch causes it to recoil back to its original shape,” he added.
The scientists worked out how to control crystallization that occurs when the material is cooled or stretched. “As the material is deformed, polymer chains are locally stretched, and small segments of the polymer align in the same direction in small areas—or domains—called crystallites, which fix the material into a temporarily deformed shape,” explained the university, in its press release. “As the number of crystallites grows, the polymer shape becomes more and more stable, making it increasingly difficult for the material to revert back to its initial—or ‘permanent’—shape.”
The researchers were able to alter the number and types of molecular linkers that connect individual polymer strands, as well as their distribution throughout the polymer network. This meant that they could adjust the material’s stability and precisely set the melting point at which the shape change is triggered.
Heating the polymer to temperatures near 95 degrees, just below human body temperature, causes the crystallites to break apart and the material to revert to its permanent shape, they said.