The age-old problem that glassmakers face is that glass is fragile and objects made from glass can break easily. However, researchers from the McGill University are currently working on a new type of glass that is flexible and shatterproof.
Researchers from the McGill Department of Engineering have developed a new type of glass based on natural structures found in nature, such as seashells. Professor François Barthelat headed the team and they may have finally found the holy grail of glass manufacturing, a process of manufacturing unbreakable 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."
The team published their findings in the online journal Nature. While engineers and researchers have known about the properties of nacre for a while now, replication the effect on synthetic materials has been difficult and previous efforts have produced little results. However, the team was able to duplicate the effect by using lasers to create minute cracks in the surface of glass samples to mimic the weak boundaries found in natural materials.
The researchers working on the project first used glass slides due to the convenient size of these objects as well as their availability in most labs. By creating a network of micro-cracks on the glass slides, the researchers were able to increase the strength of the slides by 200 times. When pressure is applied to the glass slides, the micro-cracks were able to stop the propagation of newer cracks that formed. For good measure, the researchers also added polyurethane to fill in the gaps in the micro-cracks. However, Barthelat believes that the polyurethane may be unnecessary due to the fact that the micro-cracks alone could stop the glass slides from breaking under pressure.
"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 team's findings may lead to a wide range of applications in glass making. The tough, flexible glass created using micro-cracks can soon be used for manufacturing anything from drinking glasses to smartphone screens.
