Look closely at snowflakes and you’ll find a unique tulle lattice whose growth is affected by environmental conditions such as temperature and humidity.It turns out that this complex self-assembly can also occur in metals, the researchers report Dec. 9. science.
In a pool of molten gallium, physicist Nicola Gaston and colleagues Growing Zinc Nanostructures Has a symmetrical hexagonal crystal frame. Gaston, of the MacDiarmid Institute for Advanced Materials and Nanotechnology at the University of Auckland in New Zealand, said the metal snowflakes could be used to catalyze chemical reactions and build electronics.
“Self-assembly is nature’s way of making nanostructures,” she said. “We’re trying to learn to do the same thing.” Figuring out how to make tiny, complex metal shapes with fewer steps and less energy could be a boon for manufacturers.
The researchers chose gallium as the growth medium because of its relatively low melting point, ability to dissolve many other metals, and the tendency for its atoms to organize loosely when in a liquid state.
After mixing the zinc into the gallium, the team subjected the alloy to high temperatures and varying pressures, then allowed the mixture to cool to room temperature. The team found that the loose arrangement of the gallium atoms seemed to prompt the crystalline zinc to bloom into symmetrical hexagonal structures, similar to natural snowflakes and other shapes. It’s a bit like how a fruit tray keeps the fruit stacked inside organized, Gaston said.
The future could be bright for studying gallium and other low-temperature liquid metals. “Don’t take the snowflake analogy too far, but [this work] really hint at a new branch of scientific discovery,” Gaston said.
