Revolutionary material could lead to 3D-printable magnetic liquid devices for the fabrication of flexible electronics, or artificial cells that deliver targeted drug therapies to diseased cells
Inventors of centuries past and scientists of today have found ingenious ways to make our lives better with magnets – from the magnetic needle on a compass to magnetic data storage devices and even MRI body scan machines.
All of these technologies rely on magnets made from solid materials. But what if you could make a magnetic device out of liquids? Using a modified 3D printer, a team of scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have done just that. Their findings, to be published July 19 in the journal Science, could lead to a revolutionary class of printable liquid devices for a variety of applications – from artificial cells that deliver targeted cancer therapies to flexible liquid robots that can change their shape to adapt to their surroundings.
“We’ve made a new material that is both liquid and magnetic. No one has ever observed this before,” said Tom Russell, a visiting faculty scientist at Berkeley Lab and professor of polymer science and engineering at the University of Massachusetts, Amherst, who led the study. “This opens the door to a new area of science in magnetic soft matter.”
For the past seven years, Russell, who leads a program called Adaptive Interfacial Assemblies Towards Structuring Liquids in Berkeley Lab’s Materials Sciences Division and also led the current study, has focused on developing a new class of materials – 3D-printable all-liquid structures.
Russell and Xubo Liu, the study’s lead author, came up with the idea of forming liquid structures from ferrofluids, which are solutions of iron-oxide particles that become strongly magnetic in the presence of another magnet. “We wondered, ‘If a ferrofluid can become temporarily magnetic, what could we do to make it permanently magnetic, and behave like a solid magnet but still look and feel like a liquid?’” said Russell.
Jam sessions: making magnets out of liquids
To find out, Russell and Liu used a 3D-printing technique they had developed with former postdoctoral researcher Joe Forth in Berkeley Lab’s Materials Sciences Division to print 1 millimeter droplets from a ferrofluid solution containing iron-oxide nanoparticles just 20 nanometers in diameter (the average size of an antibody protein).
Using surface chemistry and sophisticated atomic force microscopy techniques, staff scientists Paul Ashby and Brett Helms of Berkeley Lab’s Molecular Foundry revealed that the nanoparticles formed a solid-like shell at the interface between the two liquids through a phenomenon called “interfacial jamming.” 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.
To make them magnetic, the scientists placed the droplets by a magnetic coil in solution. As expected, the magnetic coil pulled the iron-oxide nanoparticles toward it.
But when they removed the magnetic coil, something quite unexpected happened.
Like synchronized swimmers, the droplets gravitated toward each other in perfect unison, forming an elegant swirl “like little dancing droplets,” said Liu, who is a graduate student researcher in Berkeley Lab’s Materials Sciences Division and a doctoral student at the Beijing University of Chemical Technology.
Somehow, these droplets had become permanently magnetic. “We almost couldn’t believe it,” said Russell. “Before our study, people always assumed that permanent magnets could only be made from solids.”
Measure by measure, it’s still a magnet
All magnets, no matter how big or small, have a north pole and a south pole. Opposite poles are attracted to each other, while the same poles repel each other.
Through magnetometry measurements, the scientists found that when they placed a magnetic field by a droplet, all of the nanoparticles’ north-south poles, from the 70 billion iron-oxide nanoparticles floating around in the droplet to the 1 billion nanoparticles on the droplet’s surface, responded in unison, just like a solid magnet.
Key to this finding were the iron-oxide nanoparticles jamming tightly together at the droplet’s surface. With just 8 nanometers between each of the billion nanoparticles, together they created a solid surface around each liquid droplet.
Somehow, when the jammed nanoparticles on the surface are magnetized, they transfer this magnetic orientation to the particles swimming around in the core, and the entire droplet becomes permanently magnetic – just like a solid, Russell and Liu explained.
The researchers also found that the droplet’s magnetic properties were preserved even if they divided a droplet into smaller, thinner droplets about the size of a human hair, added Russell.
Among the magnetic droplets’ many amazing qualities, what stands out even more, Russell noted, is that they change shape to adapt to their surroundings. They morph from a sphere to a cylinder to a pancake, or a tube as thin as a strand of hair, or even to the shape of an octopus – all without losing their magnetic properties.
The droplets can also be tuned to switch between a magnetic mode and a nonmagnetic mode. And when their magnetic mode is switched on, their movements can be remotely controlled as directed by an external magnet, Russell added.
Liu and Russell plan to continue research at Berkeley Lab and other national labs to develop even more complex 3D-printed magnetic liquid structures, such as a liquid-printed artificial cell, or miniature robotics that move like a tiny propeller for noninvasive yet targeted delivery of drug therapies to diseased cells.
“What began as a curious observation ended up opening a new area of science,” said Liu. “It’s something all young researchers dream of, and I was lucky to have the chance to work with a great group of scientists supported by Berkeley Lab’s world-class user facilities to make it a reality,” said Liu.
Learn and see more: New Laws of Attraction: Scientists Print Magnetic Liquid Droplets
The Latest on: 3D-printable magnetic liquid devices
via Google News
The Latest on: 3D-printable magnetic liquid devices
- Sub-nanosecond phase coherence wins Spectrum a place in mini-MRI machineon May 18, 2021 at 3:13 am
Quick tech support and sub-nanosecond phase coherence won German data acquisition card maker Spectrum a place in a mini MRI machine that has been designed ...
- The FDA is testing odd magnet health claims – but not because of vaccineson May 14, 2021 at 2:17 pm
Your arm won’t be magnetic after the COVID-19 vaccine, but the US FDA is undertaking a review of how implanted medical devices like pacemakers can be temporarily affected by the latest ...
- Metal nanostructures sculpted in mid-air by magnetic fieldson May 11, 2021 at 9:11 am
Researchers from the University of California (UC)-Riverside have used electromagnetic fields to direct the shapes formed by vapourised metal nanoparticles.
- A seamlessly integrated device of micro-supercapacitor and wireless charging with ultrahigh energy density and capacitanceon May 11, 2021 at 4:05 am
Miniaturized energy storage devices integrated with wireless charging bring opportunities for next generation electronics. Here, authors report seamlessly integrated wireless charging ...
- Wireless system lets one device sequentially trigger multiple implantson May 10, 2021 at 5:00 pm
Taking things a step further, scientists are now able to activate multiple implants sequentially, still using just one transmitting device. First of all, why would anyone want to trigger two or ...
- 3D Printering: Wash Parts Better And Make Solvent Last Longeron May 10, 2021 at 5:00 pm
It’s not as refined of a device, but at a regular price of $219 ... like PLA for example. My 3D-printable design for a standoff grill is available here and it can be easily resized to ...
- Superconducting Magnets Market Forecast to Reach $1.6 Billion by 2025on May 6, 2021 at 7:14 pm
Superconducting Magnets Market is forecast to reach $1.6 billion by 2025, after growing at a CAGR of 5.6% during 2020-2025. With rise in the consumption medical equipment and MRIs demand, the ...
- Physicists find a novel way to switch antiferromagnetism on and offon May 5, 2021 at 5:00 pm
The absence of net magnetization in an antiferromagnet makes it impervious to any external magnetic field. If they were made into memory devices, antiferromagnetic bits could protect any encoded ...
- Magnetic valve developed for comet lander finds job flavoring drinkson May 1, 2021 at 4:04 pm
As a result, the aerospace field often produces very clever devices that can outperform their much more complicated terrestrial counterparts. A case in point is a magnetic valve made available by ...
- Properties of chromium tribromide show path to innovative electronic deviceson April 22, 2021 at 7:24 am
The recently reported magnetic ordering in two-dimensional materials, such as chromium tribromide (CrBr3), opens new possibilities for fabrication of magnetoelectronic devices based on 2D systems ...
via Bing News