Researchers make twisted nanobelts
Rigid, not springy
Researchers at the Georgia Institute of Technology have discovered a new, helical, zinc-oxide nanostructure that could be very useful to engineers working on nanoscale devices that rely on electromechanical coupling, such as sensors, resonators and transducers.
Although the nanostructure looks like a spring, it is actually rigid, rather than elastic, and holds its shape even when it is isolated. They exist in both right and left handed versions. Production tends to split 50-50 between the two.
The nano-helix is part of the nanobelt family of structures. It is based on a superlattice composed of alternating single crystal 'stripes'. These stripes, each around 3.5nm wide, are offset from each other by 5 degrees or so. This is enough to create twisting forces that curl the belts into the spring-like shape.
Nanosprings, by contrast, are twisted by carefully balancing the electrostatic forces created by the electrical charges along each edge.
Professor Zhong Lin Wang, from the School of Materials Science and Engineering at the Georgia Institute of Technology explains that although the structure is brand new, the properties are very similar to those of existing nanobelt materials, in that they are semiconductors, and have piezoelectric properties which makes them good for electromechanical coupling.
Wang noted: "From them we can make resonators, place molecules on their surfaces to create frequency shifts - and because they are piezoelectric, make electromechanical couplings."
The Georgia Institute of Technology's press release has more details here. ®