Shape-Memory Strand Lifts 1,000 Times Its Weight
A new shape-shifting material can be stretched, bent, coiled and tied in knots. But these strands have a secret.
When these materials encounter just the right trigger temperature, they suddenly go right back to their original form — even if that means lifting many times their weight to get there.
This unusual material, called a shape-memory polymer, comes from associate chemical engineering professor Mitchell Anthamatten, graduate student Yuan Meng, and their team at the University of Rochester. They programmed the crystalline structures inside the material to melt and return to their initial state at precise temperatures.
Unlike other elastic polymers, this one can be triggered at room temperature or just by human touch. In a video demo, the engineers stretched the material into a tight coil using tweezers. When the coil dropped into a human hand, it unfurled like magic.
“Our shape-memory polymer is like a rubber band that can lock itself into a new shape when stretched,” Anthamatten said in a university press release. “But a simple touch causes it to recoil back to its original shape.”
They also store lots of elastic energy, which means being able to do work as they change shape. For example, tying one strand around a toy truck, stretching it out, and then turning on a space heater nearby was enough to pull the truck up an incline.
A strand the size of a shoelace could lift a one-liter soda bottle, according to the researchers. That’s 1,000 times its weight. The team will be publishing their results in the Journal of Polymer Science Part B: Polymer Physics this week.
Watch the material perform tricks here:
Those feats are all very impressive for one small amount of plastic material, but the University of Rochester team envisions real-world applications for their invention. Medically, this could make for perfect sutures or more responsive artificial skin.