3-D-Printed Structures ”Remember” Their Shapes

Engineers from MIT and Singapore University of Technology and Design (SUTD) are using light to print three-dimensional structures that “remember” their original shapes. Even after being stretched, twisted, and bent at extreme angles, the structures — from small coils and multimaterial flowers, to an inch-tall replica of the Eiffel tower — sprang back to their original forms within seconds of being heated to a certain temperature “sweet spot.” For some structures, the researchers were able to print micron-scale features as small as the diameter of a human hair — dimensions that are at least one-tenth as big as what others have been able to achieve with printable shape-memory materials. The team”s results were published earlier this month in the online journal Scientific Reports. Nicholas X. Fang, associate professor of mechanical engineering at MIT, says shape-memory polymers that can predictably morph in response to temperature can be useful for a number of applications, from soft actuators that turn solar panels toward the sun, to tiny drug capsules that open upon early signs of infection.