The ink, made from silver nanoparticles synthesized with biobased polymers, becomes electrically conductive after heat treatment. This capability enables the printing of electric circuits. The printer, using electrohydrodynamic printing, can jet ink under an electric field at ultra-fine resolutions, eliminating the reliance on gravity for deposition. The combination could allow astronauts to repair equipment or produce advanced electronic components in the zero-gravity environment of space.

Testing in Microgravity
The experiments took flight aboard a NASA aircraft performing parabolic maneuvers to simulate microgravity. Jiang described the flights as a "roller coaster," with the aircraft cycling between altitudes of 24,000 and 32,000 feet. Each dive provided about 10 seconds of zero gravity, offering researchers brief windows to test their technology.

"It was exciting and new," Jiang said, though the experience came with challenges, including motion sickness and the need for meticulous preparation. Early tests faced setbacks when vibrations caused the printer to lose stability. However, with adjustments and additional flights, the team achieved promising results.

"This proof-of-concept microgravity experiment proves the unique capability of [electrohydrodynamic] printing under zero-gravity conditions and opens a new venue for future on-demand manufacturing in space," the researchers wrote in a paper published by 'American Chemical Society Applied Materials and Interfaces'.

A Breakthrough Nanoink
A key innovation from Jiang's lab was the development of a unique method to synthesize the nanoink using silver nanoparticles. The ink incorporates a biobased polymer, 2-hydroxyethyl cellulose, which is derived from plant biomass. This material, typically used as a thickening agent, proved to be a stable and cost-effective component for high-resolution ink jet printing.

"There is a lot of biomass in Iowa," Jiang noted. "So, we're always trying to use these biobased molecules. They make a wonderful polymer that does all the tricks for us."

Sara Nelson, director of the NASA Iowa Space Grant Consortium, emphasized the importance of the project: "We are thrilled to have supported Dr. Jiang's research. His work has helped to build Iowa's research infrastructure and is an important part of NASA's strategic mission."

The Iowa State University Research Foundation has filed a patent for the nanoink and its associated technology, which is now available for licensing.

Toward the Future of Space Manufacturing
"This success is really just the beginning," Jiang said. "As humanity ventures deeper into space, the need for on-demand manufacturing of electronics in orbit is no longer science fiction; it is a necessity."

The team is already considering the development of 3D printing systems capable of producing additional electronic components, including semiconductors. Jiang highlighted the broader challenge: "You can't just make one component and assemble an electronic device."

As space exploration advances, technologies like nanoink-based 3D printing could become a critical component of in-situ manufacturing, enabling astronauts to construct and repair essential equipment far from Earth.

Related Links
Materials Science And Engineering at Iowa State
Space Technology News - Applications and Research