Weâ€™re around magnets so much, itâ€™s easy to forget theyâ€™re kind of magic. Not only do magnets make for fun toys, they can attract or repel objects from a distance through an invisible force, they can create electricity (and vice versa) and they can make cool new tools and materials possible.
A team of mechanical engineers from MIT and the New Jersey Institute of Technology has gone down that last path, publishing in Nature today a new method of producing soft, programmable materials. Their little creations can jump, bend, catch, crawl and more, and only look slightly creepy while doing it.
Smart materials that can change shape on their own are nothing new, but thanks to their magnetic underpinnings, the teamâ€™s creations can transform in just a fraction of a second, and are controlled entirely remotely by altering the magnetic fields in a room.
The key is in their production. The team uses as a base a soft, flexible material (silicone rubber) embedded with ferromagnetic particles (a neodymium-iron-boron alloy) â€” little bits of stuff that react to magnetic fields. Then they use a 3D printer to create the actual design, but crucially the printer itself is also magnetized, so the magnetic bits are aligned exactly how the designers want. And different parts of the material can be aligned different ways.
As the above video narrates, â€œThe result is a material with a non-uniform polarity, meaning each part of the structure can respond differently to a magnetic charge.â€�
Thatâ€™s what gives the labâ€™s creations so much flexibility and helps impart that lifelike look. Since the things are elastic, as soon as the magnetic field goes away, they can snap back to their regular â€œresting stateâ€� look.
Itâ€™s not just cool (and creepy). This technique can be useful for novel robot designs and materials constructions, as well as biomedical devices. In one of the examples, the material wrapped up a pill, rolled over a ways and deposited it while crawling away â€” or, as the authors put it, it transported a pharmaceutical dose. A tiny device that can operate remotely in an enclosed space would be mighty handy for future doctors.
But beyond that, think of the toy possibilities â€” the kids, and office workers, of the future wonâ€™t know how good they have it!