MIT engineers have created 3D-printed, shape-shifting, structures whose movements can be controlled with a wave of a magnet.
The strange collection of soft structures can be magnetically manipulated and includes a smooth ring that wrinkles up, a long tube that squeezes shut, a sheet that folds itself, and a spider-like "grabber" that can crawl, roll, jump and snap together fast enough to catch a passing ball.
Each piece is created using a newly developed type of 3D-printable ink that has been infused with tiny magnetic particles. Researchers fitted an electromagnet around the nozzle of a 3D printer, which caused the magnetic particles to swing into a single orientation as the ink was fed through the nozzle.
By controlling the magnetic orientation of individual sections in the structure, the researchers can produce structures and devices that can almost instantaneously shift into intricate formations, and even move about, as the various sections respond to an external magnetic field.
The team’s magnetically activated structures fall under the general category of soft actuated devices – squishy, moldable materials that are designed to shape-shift or move about through a variety of mechanical means. For instance, hydrogel devices swell when the temperature or pH changes; shape-memory polymers and liquid crystal elastomers deform with sufficient stimuli such as heat or light; pneumatic and hydraulic devices can be actuated by air or water pumped into them, and dielectric elastomers stretch under electric voltages.
Instead of making structures with magnetic particles of the same, uniform orientation, the MIT team looked for ways to create magnetic "domains" which are individual sections of a structure, each with a distinct orientation of magnetic particles.
When these particles are exposed to an external magnetic field, each section should move in a distinct way, depending on the direction its particles move in response to the magnetic field. In this way, the group surmised that structures should carry out more complex articulations and movements.
Have a look at the video, below, to see the crawling structure in action.