Researchers take cue from seashells to create ‘unbreakable’ glass

Taking a cue from the designs on seashells, researchers in Canada have designed a new type of glass that can bend but is less likely to break.

Scientists from McGill University's Department of Mechanical Engineering used this bio-engineering to "significantly increase" the toughness of glass.

"Mollusk shells are made up of about 95 percent chalk, which is very brittle in its pure form. 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," said research team leader Prof. François Barthelat.

Barthelat said past attempts to recreate the structures of nacre have been challenging, as he likened it to building a LEGO wall with microscopic building blocks.

The team studied the internal "weak" boundaries or edges in natural materials like nacre, and used lasers to engrave networks of 3D micro-cracks in glass slides to create similar weak boundaries.

With their work, the team increased the toughness of glass slides 200 times compared to non-engraved slides.

"By engraving networks of micro-cracks in configurations of wavy lines in shapes similar to the wavy edges of pieces in a jigsaw puzzle in the surface of borosilicate glass, they were able to stop the cracks from propagating and becoming larger," the university said.

The team then filled the micro-cracks with polyurethane, although Barthelat said this may not be essential since the patterns of micro-cracks are enough to keep the glass from shattering.

Scaling

Barthelat said the process may be easy to scale up to any size of glass sheet, since people are already engraving logos and patterns on glass panels.

“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,” he said.

In the future, he said they may work with ceramics and polymers. — VC, GMA News