University scientists have discovered a new type of shape-memory polymer that can be programmed to retain a temporary shape before it is triggered by heat to revert back to its original form. Associate Professor of Chemical Engineering Mitch Anthamatten led his research team to this breakthrough, which made the rounds on social media recently.
“We also engineered these materials to store large amounts of elastic energy, enabling them to perform more mechanical work during their shape recovery,” Anthamatten said in a University press release. Since the polymer, capable of lifting 1,000 times its own weight, can undergo a shape change triggered by body heat alone, it could prove to be a potentially useful technology in healthcare and clothing industries.
“Our shape-memory polymer is like a rubber band that can lock itself into a new shape when stretched,” Anthamatten said. “But a simple touch causes it to recoil back to its original shape.”
Anthamatten explained that the key to creating the new polymer was learning how to control crystallization when the material is stretched or cooled. Small segments of the polymer align in the same areas, called crystallites, while polymer chains are locally stretched as the material is deformed. The polymer shape becomes more and more stable as the number of crystallites grows, which makes the process of returning back to its initial shape increasingly difficult.
By including molecular linkages to connect the individual polymer strands, Anthamatten’s group discovered a way to tune the trigger temperature. After experimenting with the number and type of linkages used—which inhibit crystallization when the material is stretched—they were able to adjust the material’s stability and precisely set the melting point at which the shape change is activated.
Anthamatten believes that the shape-memory polymer could have a variety of applications, including sutures, artificial skin, body-heat assisted medical dispensers, and self-fitting clothing.