Microwaving New Materials
Reeja Jayan has made a breakthrough in our understanding of how microwaves affect materials chemistry, laying the groundwork for tailor-made ceramic materials with new electronic, thermal, and mechanical properties.
She and her student Nathan Nakamura exposed tin oxide (a ceramic) to 2.45 GHz microwave radiation and figured out how to monitor (in situ) atomic structural changes as they occurred. This discovery is important because she demonstrated that microwaves affected the tin oxide’s oxygen sublattice via distortions introduced in the local atomic structure. Such distortions do not occur during conventional materials synthesis (where energy is directly applied as heat).
Unlike prior studies, which suffered from the inability to monitor structural changes while the microwaves were applied, Jayan developed novel tools (a custom-designed microwave reactor enabling in-situ synchrotron x-ray scattering) for studying these dynamic, field-driven changes in local atomic structure as they happen. By revealing the dynamics of how microwaves affect specific chemical bonds during the synthesis, Jayan is laying the groundwork for tailor-made ceramic materials with new electronic, thermal, and mechanical properties.
“Once we know the dynamics, we can use this knowledge to make materials that are far away from equilibrium, as well as devise new energy-efficient processes for existing materials, such as 3D printing of ceramics,” she says. The commercialization of additive manufacturing of metals and plastics is widespread, but the same cannot be said for ceramic materials. 3D printing of ceramics could advance industries ranging from healthcare—imagine artificial bones and dental implants—to industrial tooling and electronics—ceramics can survive high temperatures that metals can’t. However, integrating ceramic materials with today’s 3D printing technologies is difficult because ceramics are brittle, ultrahigh temperatures are required, and we don’t understand how to control their properties during printing processes.
“Another takeaway from this research is that microwaves can do more than just heating. They can have a non-thermal effect, which can rearrange the structure of materials like a jigsaw puzzle,” says Jayan. Building on this concept, she is investigating how to use microwaves to engineer new materials.
The results of Jayan’s research were published in the Journal of Materials Chemistry A. The paper was recognized as part of the 2020 Emerging Investigators Issue of the journal. Jayan’s work was supported by a Young Investigator grant from the U.S. Department of Defense, Air Force Office of Scientific Research.
Written by Sherry Stokes, read the original article here.