Researchers have discovered a new phase of glass by creating an ultrathin layer of liquid that forms a high-density glass. The new version is denser and more stable while still extremely slim and the team believes that it can be employed as a brand-new material. The approach could also be used on other non-glassy substances.
The starting point, as reported in the Proceedings of the National Academy of Sciences, is the creation of an ultra-thin film of glass. Glass is an amorphous solid, which means that it looks like a liquid in the way molecules are arranged but it behaves like a solid. But when glass is made into films that are just nanometers in thickness, these liquid-like properties are dominant and this often leads to degradation and instability. These films are used in OLED screens and optical fibers.
The traditional approach is to cool down liquid glass into these ultrathin films. But Dr Yi Jin, working in the lab of Zahra Fakhraai at the University of Pennsylvania, instead built them by turning a glass vapor into a solid. The unconventional approach delivered unexpected results. The ultrathin film represents a different liquid phase for glass and it has a density higher than a crystal. These films don’t suffer from the limitations of those made by traditional methods.
“Yi kept discovering different properties, none of the data made sense, and so we dug deeper until we had enough data to put a picture together,” first author Dr Fakhraai, associated professor of Chemistry at the University, said in a statement. “There are a lot of interesting properties that came out of nowhere, and nobody had thought that in thin films you would be able to see these phases. It’s a new type of material.”
The confirmation that this is a new phase comes from looking at how the molecules are organized in the material. Just like graphite in a pencil and diamond – both are made of carbon atoms but in wildly different configurations. Thanks to equipment at Brookhaven National Laboratory, they confirmed that this was not a crystal but a newly reported liquid phase of glass. And, possibly, this is not exclusive to glass.
“We’re developing materials that are trying to go down in terms of scale,” says Jin about his current work in the materials science industry. “From what we see in glasses, there could also be interesting phenomena that emerge from other materials, like metallic materials that are commonly used in semiconductors, for example.”
The team is currently running some follow-up investigations to better understand this new material and the properties of glass in general.
