Last updated January 11, 2018 at 10:43 am
A breakthrough in our understanding of how glasses form could herald a revolution in technology from improving the efficiency of solar cells and light emitting diodes, to better optics in telescopes and optical fibres.
New research suggests that glasses formed by vapour deposition become ultra-stable virtually immediately unlike traditional glasses that take thousands of years of ageing to reach the same state.
The ability to make ultra-stable glasses quickly is “one of the larger innovations in glass technology”, said Peter Harrowell, Professor of Theoretical Chemistry at the University of Sydney.
We have been using glass as a material since at least 3500 BCE. Made largely of silicon dioxide, it does not form regular crystals. As the liquid state of silicon dioxide cools, the molecules are stuck in random arrangements.
In the glass state, its molecules wiggle around trying to find more stable arrangements with the material slowly changing over time. It usually takes thousands of years for glass to become harder and denser in its ultra-stable state.
The process called ‘vapour deposition’, however, shortcuts this process. It slowly grows the glass by putting little bits of material onto a surface at a time.
The idea studied in this new research is that the molecules on the surface can wiggle around a lot more than usual, so they can find their preferred positions very quickly. By the time the next layer grows, the parts underneath it are already ultrastable.
This results in a material that is much more durable, more tough, and generally more stable, formed in around an hour, rather than a thousand years.
“The possibility of being able to adjust their properties through vapour deposition is an important advance,” says Harrowell. “It will allow you to control the orientation of molecules in organic electronic devices.” This will increase their efficiency.
Scientifically, “glass” refers to any amorphous solid, not just the glass we are used to in everyday life. These other kinds of glass behave in the same way, with the same, very slowly formed, ultrastable state.
While previous work has shown that vapour deposited glasses are ultrastable, this study helps to explain why.
It also suggests ways to improve manufacturing to make this process as fast as possible, and how to produce the most stable possible glasses. This work also suggests ways to fine tune the properties of glasses by modifying the deposition process.
This leads towards more durable and efficient optical devices as well as protective coatings on glass and even steel tools, and even antibacterial coatings that are tough enough to be used on everyday surfaces, such as door handles.