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WashU engineers to study nanoparticles’ behavior in low-temperature plasma

Products from artificial joints to semiconductor circuits to plastic bags are made using the fourth state of matter, or plasma, which is an ionized gas. Plasma changes properties depending on its temperature, and when the temperature is low, the substance is strongly nonequilibrium, meaning it changes over time.

Elijah Thimsen

Elijah Thimsen, principal investigator of the Interface Research Group at Washington University in St. Louis, will study the behavior of nanoparticles in low-temperature plasmas that may lead to the production of novel materials and novel states of matter.

Thimsen, assistant professor of energy, environmental & chemical engineering in the School of Engineering & Applied Science, received a three-year, $248,984 grant from the National Science Foundation to study the vaporization of nanoparticles in low-temperature plasmas. He will explore a new aerosol mechanism in these plasmas that has not been previously studied. The mechanism allows for materials, such as metals, to vaporize at room temperature, due to the nonequilibrium environment within the plasma.

“In addition to this being fundamentally interesting, this mechanism allows monodispersed nanoparticles to be produced that are made of materials for which production methods are unknown,” Thimsen said. “With the theoretical limits still unknown for processing material into new configurations via interactions with low-temperature plasmas, there also is a chance for experimental discovery of novel processes to alter materials in unexpected ways.”

Thimsen said preliminary evidence supports the new mechanism, which would be applicable to many different materials.

“The goal of the project is to generalize the mechanism and to use it to synthesize materials that are desired by the nanomaterials community, but have nevertheless remained elusive,” he said.


The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 94 tenured/tenure-track and 28 additional full-time faculty, 1,200 undergraduate students, 1,200 graduate students and 20,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.