The name of Ethan Secor’s startup company – “Contour Circuits” – is a great description of the technology he and his research group are developing.
They’re learning to print precise and complex electronic circuits on curved and 3D surfaces.
Step one of the process is understanding the mechanics and physics of a technology called aerosol jet printing, which, similar to an office inkjet printer, deposits droplets of ink to create a pattern defined by software.
Step two is monitoring and controlling the printing process in real time, as ink is atomized into a fine mist that’s carried by a gas flow and squeezed through a nozzle for printing at a resolution of just 10 to 100 millionths of a meter.
Step three is building custom printers and the software that controls them. One such printer is mounted to an articulated robotic arm, allowing the printer nozzle to work over a curved surface. That “introduces greater complexity for motion planning and alignment,” according to a summary of the technology.
“Right now, the work that’s getting me excited is the conformal printing,” said Secor, an Iowa State University associate professor of mechanical engineering. “For the next two to three years, that’s going to be a big effort. We’ll be pushing to develop applications for the technology.”
Those applications could include electronics for use by the energy, healthcare, manufacturing, aerospace, communications and security industries.
In recognition of that research program and other accomplishments – including early career awards from the U.S. National Science Foundation, the Defense Advanced Research Projects Agency and the Office of Naval Research – Secor is being honored this fall with an Iowa State University Award for Early Achievement in Research.
The Breadth of the Work
Secor describes his introduction to aerosol jet printing as an accident.
“In graduate school (at Northwestern University in Evanston, Illinois), I wanted to work on energy,” he said. “But the professor I wanted to work with (Mark C. Hersam) had a project involving printed electronics.”
Secor started by designing graphene inks for various printing technologies. That led to developing applications for graphene inks in flexible electronics, liquid metal electronics, microsupercapacitors and lithium-ion batteries. Those inks were promising enough to be distributed by Sigma-Aldrich Inc., and they’re still sold today.
Why not switch back to an energy project?
“What kept me there was the breadth of the work,” he said.
Working with printed electronics can mean pulling in collaborators from all over a university, including electrical engineers, mechanical engineers, materials scientists and chemists.
“There are a lot of different perspectives needed,” he said. “And that has kept me engaged and learning.”
One Iowa State collaborator is Adarsh Krishnamurthy, a professor of mechanical engineering and an associate director of the university’s Translational AI Center.
“In our work together, we have had to bring together expertise in materials, hardware, robotics, geometric modeling and computational methods to make aerosol jet printing work reliably on complex 3D curved surfaces,” he said. “Ethan is very good at envisioning how all of those pieces fit together.”
And, Krishnamurthy said, Secor knows how to work with a research team.
“He is also an excellent collaborator who is open to ideas from other disciplines, rigorous about technical details and focused on turning fundamental research into capabilities that can actually be demonstrated and used.”
Pursuing the Practical
As an engineer, Secor is motivated to apply scientific research for practical benefits.
“Researchers have developed many creative and impressive demonstrations of printed hybrid electronics,” he said. “But to move those beyond a laboratory environment, reliability is key.”
Secor said there are two sides to that reliability: consistency of the manufacturing process itself, and stability of the printed devices. Secor’s lab is working on both.
Across five projects over the past six years, Secor’s team developed a sensor to monitor the printing process and automatically make corrections. His group has since installed these systems at several industry, government and academic sites from New York to California.
On the other side of reliability, a recent grant from the U.S. National Science Foundation has Secor studying new ink materials for printed electronics that hold up in the extreme environments of space, including high and low temperatures.
The challenge isn’t necessarily with the silicon-based chips that are essential to today’s electronics. The failures often occur at the interface between those semiconductors and larger circuits, Secor said.
Solve that problem, and we all could benefit:
“Electronic systems that can function in extreme environments are highly relevant for energy, infrastructure, aerospace, and space applications,” the researchers wrote in a project summary.
NASA is also interested in potential benefits for space electronics and has awarded the startup established by Secor and his former graduate student, Jeremy Rurup, with a $150,000 contract from the federal government’s Small Business Technology Transfer program that supports technology development and commercialization.
As the company incubates in its small space at the Roy J. Carver Co-Laboratory on the north side of campus, Secor is also looking ahead to future research ideas.
One idea that needs development is using aerosol jet printing to blend different materials during deposition, in a sense shifting from printing in black and white to gray scale, he said.
So yes, he’s confident there’s more to keep him engaged in the challenges of printed electronics.
He is, after all, the kind of engineer who’s ready to dive into a technology so he can advance a project.
As a post-doctoral researcher at the U.S. Department of Energy’s Sandia National Laboratories in New Mexico, “I learned how to build a printer and that opened up a lot of research directions,” Secor said. “Now we build and customize our own hardware. So, while other research groups are playing with a black box, we can open it up, understand how it works and improve on it.”