Glass That Bends Without Breaking Inspired By Seashells; 200 Times Stronger Than Regular Material
Researchers have invented a new type of exceptionally strong glass that bends but does not break.
The new glass is inspired by the structure of seashells, a McGill University news release reported.
"Mollusk shells are made up of about 95 [percent] chalk, which is very brittle in its pure form," Professor François Barthelat said in the news release. "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."
Researchers have tried to recreate nacre in the past, but it has been quite a challenge.
"Imagine trying to build a Lego wall with microscopic building blocks. It's not the easiest thing in the world." Instead, what he and his team chose to do was to study the internal 'weak' boundaries or edges to be found in natural materials like nacre and then use lasers to engrave networks of 3D micro-cracks in glass slides in order to create similar weak boundaries. The results were dramatic," Barthelat said.
The research team successfully increased the toughness of glass microscope slides by 200 times by configuring wavy "micro cracks" similar to a jigsaw puzzle into its surface; the team was able to keep the cracks from "propagating and becoming larger." They filled the tiny cracks with polyurethane, although this was only a precaution and not a necessity, the researchers said, the news release reported.
The researchers believe this technique can be used on glass of any size.
"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," Barthelat said. "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."