Researchers from North Carolina State University and The University of Texas at Austin have found a special property in complex nanostructures that had previously only been found in simple nanostructures. They have also uncovered the internal workings of the materials that enable this property.
The findings were reported in a new paper that appeared this week in the Proceedings of the National Academy of Sciences. The oxide-based “nanolattices” are tiny, hollow materials that resemble the structure of sea sponges.
As one of the paper’s lead authors and a professor in NC State’s Department of Mechanical and Aerospace Engineering, Yong Zhu noted, “This has been seen before in simple nanostructures, like a nanowire, which is about 1,000 times thinner than a hair.” But this is the first instance of it in a 3D nanostructure that we have observed.
The issue is referred to as anelasticity. It has to do with how materials respond over time to stress. Tiny defects responded to the stress gradient by slowly moving when the materials examined in this paper were bent. When the stress is removed, the tiny flaws slowly move back to where they were before. This is called anelastic behavior.
The researchers also found that these defects have energy dissipation properties when they oscillate. This implies that they have the ability to dissipate vibrations and pressure waves. The material might one day be used as a shock absorber, but only on a very small scale because it is so light and thin. Researchers think it could be used in electronic chips or other devices that use a lot of electronic parts.
According to Chih-Hao Chang, an associate professor in the Walker Department of Mechanical Engineering at UT Austin, “You could possibly put this material under the semiconductor chips and protect them from outside impact or vibration.”
The next step is to control these anelastic properties now that they have been identified. Researchers will look at the geometry of the nanostructures and do experiments with different loading conditions to find out how to improve the non-elastic performance for energy dissipation applications.
