Scientists Print Magnetic Liquid Droplets

The Berkeley Lab's new liquid is the primary to be permanently so.

Magnets are widely used today for all sorts of scenarios from medical devices to storing data inside computers.

What has the magnetic properties of a solid magnet, but the mechanical properties of a liquid? But what if you could make a magnetic device out of liquids? Now, usually all the magnetic devices that produce magnetic fields are composed of solid materials, however, the latest innovation a team of scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) makes use of liquid for magnetic devices. This could include artificial cells that can deliver targeted cancer therapies, or flexible liquid robots that can change their shape to adapt to their surroundings. However, the closest thing we have to a magnetic liquid is a class known as of liquids called ferrofluids - Made up of iron-oxide particles suspended in liquids, these supplies are exclusively magnetic briefly when exposed to other magnets.

Russell, who is also a visiting professor at the Berkeley National Lab, adds that the technique extends scientific knowledge of magnetic materials, and should encourage research into the deep-seated mechanism of how liquid magnets form.

Relatives of victims condemn Srebrenica ruling
The ruling upheld a decision made in 2017 at The Hague , but reduced the Dutch government's liability from 30% to 10%. The country's government has stated that they accept the new verdict and the 10% damage liability.

"This opens the door", Russell said, "to a new area of science in magnetic soft matter". Russell also leads a program called Adaptive Interfacial Assemblies Towards Structuring Liquids in Berkeley Lab's Materials Sciences Division, where for the past seven years he has been developing 3D printable all-liquid structures. The new magnetic liquid uses iron oxide nanoparticles, which is also a popular choice for ferrofluid, so there are no surprises there.

This is what the team chose to use for their nanoparticle suspension, printing droplets just one millimetre in diameter. Researchers further made use of surface chemistry and other advanced atomic force microscopy techniques. This causes the nanoparticles to crowd at the droplet's surface, "like the walls coming together in a small room jampacked with people", said Russell. Every iron-oxide nanoparticle in every droplet was responding to the magnetic subject directly, and since so many were jammed together on the floor, they essentially have been forming a stable magnetic shell. However, unlike normal ferrofluids, this magnetism remained even after the coil was eliminated. This leads to them losing out on their magnetization properties once the applied magnetic field is removed. The droplets began swirling around each other in unison.

But with this new liquid, the nanoparticles started spinning towards each other in unison, like synchronised swimmers, or "little dancing droplets", according to engineer Xubo Liu of the Beijing University of Chemical Technology.

At nano scale, traditional ferromagnetic materials become magnetic only in the presence of a magnetic field. "We nearly couldn't believe it", said Russell.

Recommended News

We are pleased to provide this opportunity to share information, experiences and observations about what's in the news.
Some of the comments may be reprinted elsewhere in the site or in the newspaper.
Thank you for taking the time to offer your thoughts.