A champagne flute, smartphone screen or bottle of beer can end up shattering on the floor if you're not careful. Glass by design is fragile, but a team of engineers aim to stop the shatter and make glass bend instead.
Researchers at McGill's Department of Mechanical Engineering, led by Prof. François Barthelat, have taken inspiration from the strong natural structure of seashells in order to "significantly increase" the toughness of glass.
"Mollusk shells are made up of about 95 per cent chalk, which is very brittle in its pure form," says Barthelat. "But nacre, or mother-of-pearl, which coats the inner shells, is made up of microscopic tablets that are a bit like miniature Lego building blocks, is known to be extremely strong and tough, which is why people have been studying its structure for the past twenty years."
How does it work? By pre-cracking glass with lasers in a puzzle-piece fashion and allowing the resultant tiny fissures to be filled with polyurethane, the material becomes capable of bending on impact. This creates a material with weak boundaries but able to withstand more pressure than you'd think.
By engraving glass slides and comparing their strength with uncracked versions, the team found that toughness was increased by up to 200 times.
"What we know now is that we can toughen glass, or other materials, by using patterns of micro-cracks to guide larger cracks, and in the process absorb the energy from an impact," says Barthelat. "We chose to work with glass because we wanted to work with the archetypal brittle material. But we plan to go on to work with ceramics and polymers in future. Observing the natural world can clearly lead to improved man-made designs."
The full paper can be found in the journal Nature Communications.
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