Cracking Nature Inspires Stronger Glass
Engineers from McGill University in Montreal, Canada, turned to nature to give them ideas as to how to make glass stronger, that doesn’t just shatter when hit or dropped, and published their paper in the journal Nature Communications.
Mollusc shells, fingernails, bones – these are all made up of tiny, brittle minerals pushed together to form a larger unit. The team studied these natural materials to find out how they were so resilient to force despite what they are made up of.
All of these natural materials feature tiny lines over them, called interfaces, and while logically this could be considered a weakness, it is actually a great way for external pressure to be deflected, by deforming slightly when pressure is applied.
A good example of the minerals building up to make a stronger whole is the shiny inside layer of some molluscs, better known as ‘mother of pearl’. It is actually around 3,000 times tougher than the minerals it is made out of.
Armed with this knowledge, the engineers decided to see how they could apply it to glass. They used a 3D laser to engrave lots of tiny fissures into a glass slide. The team then filled these miniscule cracks with a polymer and performed tests on the glass. They found the glass to be better at absorbing impacts than before, bending and yielding in slightly instead of immediately shattering. Better yet, the glass was around 200 times stronger than a standard pane.
The glass was made stronger by filling it with cracks, and while the paper explained that it might seem “counter-intuitive” to weaken a material to make it stronger, it was obviously a method that worked well in nature.
“A container made of standard glass will break and shatter if it is dropped on the floor,” explained study co-author Professor Francois Barthelat. “In contrast, a container made from our bio-inspired glass has the possibility to deform a little without completely fracturing. The container could be used again after one or more drops.”
Regular glass can also only be stretched by 0.1% before it breaks, but the new glass could be bent by almost 5%. This means that it has the potential to be a safer glass option for things like glasses and smartphones, and maybe even bullet-proof glass.
The new method is also very economical: “All that is needed is a pulse laser beam,” said Professor Barthelat. He explained that the technology can easily be applied to larger scale glass.
Could this ultimately mean that windows shattered by a stray football will be a thing of the past? That wine glass tipsily spilt onto the floor, those lost eye-glasses that have just been trodden on, the cracked iPhone screen: when this glass is being mass produced, these incidents will be nothing more than nostalgia.