Scientists accidentally 3D printed the world’s first liquid magnets

Let’s face it, polymorphic shape shifting robots will emerge one day, and I’m not just saying that because I’ve already spotted the world’s first shape shifting polymorphic materials, world’s first liquid computers, or components of ones atleast, and already discussed how one day a robots intelligence will be spread all over its body and not just in a centralised brain… no, no, no. Now though another interesting quirk in the story to create these types of robots has emerged in the development of the world’s first liquid magnets, something that happened by accident.

For the first time, scientists have announced they’ve created a permanently magnetic liquid whose liquid droplets can morph into various shapes and be externally manipulated to move around, according to a new study, and while the technology is far away from being mature enough to make a funky robot it’s another interesting step in the journey.

See the magnets in action 

We typically imagine magnets as being solid, said senior author Thomas Russell, a distinguished professor of polymer science and engineering at the University of Massachusetts Amherst in the US. “But now we know that we can make magnets that are liquid and they could conform to different shapes, and the shapes are really up to you."

The liquid droplets can change shape from a sphere to a cylinder to a pancake, he added. "We can [even] make it look like a sea urchin if we wanted." And why the hell not!? Forget robots the future is full of magnetic urchins! Anyway, back to the story.

Russell and his team created these liquid magnets by accident while experimenting with 3D printing liquids at the Lawrence Berkeley National Laboratory where Russell is also a visiting faculty scientist. The goal was to create materials that are solid but have characteristics of liquids for various energy applications.

One day, postdoctoral student and lead author Xubo Liu noticed a 3D printed material, made from magnetised particles called iron-oxides, spinning around in unison on a magnetic stir plate. So, when the team realised the entire construct, not just the particles, had become magnetic, they decided to investigate further.

Using a technique to 3D print liquids, the scientists created millimetre sized droplets from water, oil and iron-oxides. The liquid droplets keep their shape because some of the iron-oxide particles bind with surfactants, which are substances that reduce the surface tension of a liquid. The surfactants create a film around the liquid water, with some iron-oxide particles creating part of the filmy barrier, and the rest of the particles enclosed inside, Russell said.

The team then placed the millimeter-size droplets near a magnetic coil to magnetise them. But when they took the magnetic coil away, the droplets demonstrated a never seen before behaviour in liquids, they remained magnetized.

When those droplets approached a magnetic field, the tiny iron-oxide particles all aligned in the same direction. And once they removed the magnetic field, the iron-oxide particles bound to the surfactant in the film were so jam-packed that they couldn't move and so remained aligned. But those free floating inside the droplet also remained aligned.

The scientists don't fully understand how these particles hold onto the field, Russell said, adding that when they figure that out, there are many potential applications. For example, Russell imagines printing a cylinder with a non-magnetic middle and two magnetic caps. And shape shifting robots. Obs.

"The two ends would come together like a horseshoe magnet," and be used as a mini grabber," he said.

“In an even more bizarre application, imagine a mini liquid person, a smaller-scale version of the liquid T-1000 from the second Terminator movie,” he added, Bingo! “Now imagine that parts of this mini liquid man are magnetised and parts aren't. An external magnetic field could then force the little person to move its limbs like a marionette. For me, it sort of represents a sort of new state of magnetic materials.”

The findings were published in the journal Science.