Shrinky Dinks may be a thing of our childhood past, but now, scientists are using them as the basis for their research. Shrinky Dinks—sheets of polystyrene plastic that kids can draw on and cook to make jewelry, toys, and more—are being used to make durable grippers that could be the foundation of future materials or be used in soft robotics.
Shrinky Dinks are shape-memory polymers, and they undergo a dramatic transformation when exposed to heat. Manufacturers pre-stretch the sheets of polystyrene so when they’re heated above 217 F, they shrink back to their original size. Michael Dickey, Jan Genzer, and other colleagues wanted to know if they could use these properties to create cheap grippers that could retain their shape better than soft materials that are used.
The researchers used an inkjet printer and patterned black ink in various shapes onto polystyrene sheets. When they shone an infrared light on the cut-out shapes, the inked regions warmed faster than the blank areas, so the polystyrene wrapped around the object they intended to be gripped, such as a hex bolt. Once they removed the light, the gripper’s shape was locked into place.
The team indicated that grippers optimized for ink pattern, geometry, and number of panels could suspend objects more than 24,000 times their own mass for several minutes before a mechanical failure, or 5,000 times their own mass for months.
Filed Under: TECHNOLOGIES + PRODUCTS, Materials • advanced