This easy machine that makes use of the floor stress of water to seize and manipulate microscopic objects. Credit: Manoharan Lab/Harvard SEAS
A 3D-printed machine in a tank of water braids nanowires and strikes microparticles.
New antennae to entry larger and better frequency ranges might be wanted for the subsequent technology of telephones and wi-fi gadgets. One approach to make antennae that work at tens of gigahertz — the frequencies wanted for 5G and better gadgets — is to braid filaments about 1 micrometer in diameter. However, right this moment’s industrial fabrication methods received’t work on fibers that small.
“It was a shout-out-loud-in-joy moment when — on our first try — we crossed two fibers using only a piece of plastic, a water tank, and a stage that moves up and down.” — Maya Faaborg
Now a staff of engineers and scientists from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed a easy machine that makes use of the floor stress of water to seize and manipulate microscopic objects. This exceptional innovation affords a probably highly effective instrument for nanoscopic manufacturing.
The analysis was revealed within the journal Nature on October 26.
“Our work offers a potentially inexpensive way to manufacture microstructured and possibly nanostructured materials,” mentioned Vinothan Manoharan, the Wagner Family Professor of Chemical Engineering and Professor of Physics at SEAS and senior creator of the paper. “Unlike other micromanipulation methods, like laser tweezers, our machines can be made easily. We use a tank of water and a 3D printer, like the ones found at many public libraries.”
The machine is a 3D-printed plastic rectangle that’s in regards to the measurement of an previous Nintendo cartridge. The inside of the machine is carved with channels that intersect. Each channel has extensive and slim sections, just like a river that expands in some elements and narrows in others. The channel partitions are hydrophilic, that means they entice water.
Through a sequence of simulations and experiments, the scientists found that after they submerged the machine in water and positioned a millimeter-sized plastic float within the channel, the floor stress of the water precipitated the wall to repel the float. If the float was in a slim part of the channel, it moved to a large part, the place it may float as far-off from the partitions as potential.
Once in a large part of the channel, the float can be trapped within the middle, held in place by the repulsive forces between the partitions and float. As the machine is lifted out of the water, the repulsive forces change as the form of the channel modifications. If the float was in a large channel to begin, it could discover itself in a slim channel because the water stage falls and want to maneuver to the left or proper to discover a wider spot.
“The eureka moment came when we found we could move the objects by changing the cross-section of our trapping channels,” mentioned Maya Faaborg, an affiliate at SEAS and co-first creator of the paper.
“The amazing thing about surface tension is that it produces forces that are gentle enough to grab tiny objects, even with a machine big enough to fit in your hand.” — Ahmed Sherif
Next, the researchers connected microscopic fibers to the floats. As the water stage modified and the floats moved to the left or proper throughout the channels, the fibers twisted round one another.
“It was a shout-out-loud-in-joy moment when — on our first try — we crossed two fibers using only a piece of plastic, a water tank, and a stage that moves up and down,” mentioned Faaborg.
The staff then added a 3rd float with a fiber and designed a sequence of channels to maneuver the floats in a braiding sample. They efficiently braided micrometer-scale fibers of the artificial materials Kevlar. The braid was similar to a standard three-strand hair braid, besides that every fiber was 10-times smaller than a single human hair.
Next, the investigators demonstrated that the floats themselves may very well be microscopic. They constructed machines that would lure and transfer colloidal particles 10 micrometers in measurement — though the machines had been a thousand occasions greater.
“We weren’t sure it would work, but our calculations showed that it was possible,” mentioned Ahmed Sherif, a PhD pupil at SEAS and a co-author of the paper. “So we tried it, and it worked. The amazing thing about surface tension is that it produces forces that are gentle enough to grab tiny objects, even with a machine big enough to fit in your hand.”
Next, the staff goals to design gadgets that may concurrently manipulate many fibers, with the objective of constructing high-frequency conductors. They additionally plan to design different machines for micromanufacturing functions, akin to constructing supplies for optical gadgets from microspheres.
Reference: “3D-printed machines that manipulate microscopic objects using capillary forces” by Cheng Zeng, Maya Winters Faaborg, Ahmed Sherif, Martin J. Falk, Rozhin Hajian, Ming Xiao, Kara Hartig, Yohai Bar-Sinai, Michael P. Brenner and Vinothan N. Manoharan, 26 October 2022, Nature.
DOI: 10.1038/s41586-022-05234-7
The analysis was co-authored by Cheng Zeng, Ahmed Sherif, Martin J. Falk, Rozhin Hajian, Ming Xiao, Kara Hartig, Yohai Bar-Sinai and Michael Brenner, the Michael F. Cronin Professor of Applied Mathematics and Applied Physics and Professor of Physics at SEAS. It was supported partially by the Defense Advanced Research Projects Agency (DARPA), under grant FA8650-15-C-7543; the National Science Foundation through the Harvard University Materials Research Science and Engineering Center, under grant DMR-2011754 and ECCS-1541959; and the Office of Naval Research under grant N00014-17-1-3029.
