3D printing of shape-shifting structures

A team of Lawrence Livermore National Laboratory researchers has recently demonstrated the 3D printing of shape-shifting structures that can fold or unfold to reshape themselves when exposed to heat or electricity. The micro-architected structures were fabricated from a conductive, environmentally responsive polymer ink developed at the Lab.

While the approach of using responsive materials in 3D printing, often known as “4D printing,” is not new, LLNL researchers are the first to combine the process of 3D printing and subsequent folding (via origami methods) with conductive smart materials to build complex structures.

“It’s like baking a cake,” said lead author Jennifer Rodriguez, a postdoc in LLNL’s Materials Engineering Division. “You take the part out of the oven before it’s done and set the permanent structure of the part by folding or twisting after an initial gelling of the polymer.”

Ultimately, Rodriguez said, researchers can use the materials to create extremely complex parts. Through a direct-ink writing 3D printing process, the team produced several types of structures — a bent conductive device that morphed to a straight device when exposed to an electric current or heat, a collapsed stent that expanded after being exposed to heat and boxes that either opened or closed when heated.

The technology, the researchers said, could have applications in the medical field, in aerospace (in solar arrays or antennae that can unfold), as well as flexible circuits and robotic devices.