Physicists Build Muscle for Shape-Changing, Cell-Sized Robots
January 5, 2018 | Cornell UniversityEstimated reading time: 3 minutes
An electricity-conducting, environment-sensing, shape-changing machine the size of a human cell? Is that even possible?
Cornell physicists Paul McEuen and Itai Cohen not only say yes, but they’ve actually built the “muscle” for one.
With postdoctoral researcher Marc Miskin at the helm, the team has made a robot exoskeleton that can rapidly change its shape upon sensing chemical or thermal changes in its environment. And, they claim, these microscale machines – equipped with electronic, photonic and chemical payloads – could become a powerful platform for robotics at the size scale of biological microorganisms.
“You could put the computational power of the spaceship Voyager onto an object the size of a cell,” Cohen said. “Then, where do you go explore?”
“We are trying to build what you might call an ‘exoskeleton’ for electronics,” said McEuen, the John A. Newman Professor of Physical Science and director of the Kavli Institute at Cornell for Nanoscale Science. “Right now, you can make little computer chips that do a lot of information-processing … but they don’t know how to move or cause something to bend.”
Their work is outlined in “Graphene-based Bimorphs for Micron-sized, Autonomous Origami Machines,” published Jan. 2 in Proceedings of the National Academy of Sciences. Miskin is lead author; other contributors included David Muller, the Samuel B. Eckert Professor of Engineering, and doctoral students Kyle Dorsey, Baris Bircan and Yimo Han.
The machines move using a motor called a bimorph. A bimorph is an assembly of two materials – in this case, graphene and glass – that bends when driven by a stimulus like heat, a chemical reaction or an applied voltage. The shape change happens because, in the case of heat, two materials with different thermal responses expand by different amounts over the same temperature change.
As a consequence, the bimorph bends to relieve some of this strain, allowing one layer to stretch out longer than the other. By adding rigid flat panels that cannot be bent by bimorphs, the researchers localize bending to take place only in specific places, creating folds. With this concept, they are able to make a variety of folding structures ranging from tetrahedra (triangular pyramids) to cubes.
In the case of graphene and glass, the bimorphs also fold in response to chemical stimuli by driving large ions into the glass, causing it to expand. Typically this chemical activity only occurs on the very outer edge of glass when submerged in water or some other ionic fluid. Since their bimorph is only a few nanometers thick, the glass is basically all outer edge and very reactive.
“It’s a neat trick,” Miskin said, “because it’s something you can do only with these nanoscale systems.”
The bimorph is built using atomic layer deposition – chemically “painting” atomically thin layers of silicon dioxide onto aluminum over a cover slip – then wet-transferring a single atomic layer of graphene on top of the stack. The result is the thinnest bimorph ever made.
One of their machines was described as being “three times larger than a red blood cell and three times smaller than a large neuron” when folded. Folding scaffolds of this size have been built before, but this group’s version has one clear advantage.
“Our devices are compatible with semiconductor manufacturing,” Cohen said. “That’s what’s making this compatible with our future vision for robotics at this scale.”
And due to graphene’s relative strength, Miskin said, it can handle the types of loads necessary for electronics applications.
“If you want to build this electronics exoskeleton,” he said, “you need it to be able to produce enough force to carry the electronics. Ours does that.”
For now, these tiniest of tiny machines have no commercial application in electronics, biological sensing or anything else. But the research pushes the science of nanoscale robots forward, McEuen said.
“Right now, there are no ‘muscles’ for small-scale machines,” he said, “so we’re building the small-scale muscles.”
This work was performed at the Cornell NanoScale Facility for Science and Technology and supported by the Cornell Center for Materials Research, the National Science Foundation, the Air Force Office of Scientific Research and the Kavli Institute at Cornell.
Suggested Items
Book Excerpt: The Printed Circuit Assembler’s Guide to... Factory Analytics
04/24/2024 | I-Connect007 Editorial TeamIn our fast-changing, deeply competitive, and margin-tight industry, factory analytics can be the key to unlocking untapped improvements to guarantee a thriving business. On top of that, electronics manufacturers are facing a tremendous burden to do more with less. If you don't already have a copy of this book, what follows is an excerpt from the introduction chapter of 'The Printed Circuit Assembler’s Guide to... Factory Analytics: Unlocking Efficiency Through Data Insights' to whet your appetite.
Listen Up! The Intricacies of PCB Drilling Detailed in New Podcast Episode
04/25/2024 | I-Connect007In episode 5 of the podcast series, On the Line With: Designing for Reality, Nolan Johnson and Matt Stevenson continue down the manufacturing process, this time focusing on the post-lamination drilling process for PCBs. Matt and Nolan delve into the intricacies of the PCB drilling process, highlighting the importance of hole quality, drill parameters, and design optimization to ensure smooth manufacturing. The conversation covers topics such as drill bit sizes, aspect ratios, vias, challenges in drilling, and ways to enhance efficiency in the drilling department.
Elevating PCB Design Engineering With IPC Programs
04/24/2024 | Cory Blaylock, IPCIn a monumental stride for the electronics manufacturing industry, IPC has successfully championed the recognition of the PCB Design Engineer as an official occupation by the U.S. Department of Labor (DOL). This pivotal achievement not only underscores the critical role of PCB design engineers within the technology landscape, but also marks the beginning of a transformative journey toward nurturing a robust, skilled workforce ready to propel our industry into the future.
Winner of The Science Show Rakett 69 Receives Incap Scholarship
04/24/2024 | IncapThe winner of the Rakett 69 science show, Andri Türkson, who stood out as an electronics enthusiast, received a scholarship from Incap Estonia, along with an internship opportunity in Saaremaa.
Alternative Manufacturing Inc. Awarded QML Requalification to IPC J-STD-001 and IPC-A-610
04/24/2024 | IPCIPC's Validation Services Program has awarded an IPC J-STD-001 and IPC-A-610 Qualified Manufacturers Listing (QML) requalification to Alternative Manufacturing Inc (AMI).