Self-healing glass: a cracking discovery from Japan
Self-healing glass: a cracking discovery from Japan
The discovery opens the way for super-durable glass that could triple the lifespan of everyday products like car windows, construction materials, fish tanks and even toilet seats.
Yu Yanagisawa, a chemistry researcher at the University of Tokyo, made the breakthrough by chance while investigating adhesives that can be used on wet surfaces.
Does this mean you will soon be able to repair those cracks in your smartphone with a quick press of the fingers? Or surreptitiously piece together a shattered beer glass dropped after one pint too many?
Well, not quite. Not now and in fact, not in the near future.
But it does open a window of opportunity for researchers to explore ways to make more durable, lightweight, glass-like items, like car windows.
In a lab demonstration for AFP, Yanagisawa broke a glass sample into two pieces.
He then held the cross sections of the two pieces together for about 30 seconds until the glass repaired itself, almost resembling its original form.
To demonstrate its strength, he then hung a nearly full bottle of water from the piece of glass — and it stayed intact.
The organic glass, made of a substance called polyether thioureas, is closer to acrylic than mineral glass, which is used for tableware and smartphone screens.
Other scientists have demonstrated similar properties by using rubber or gel materials but Yanagisawa was the first to demonstrate the self-healing concept with glass.
The secret lies in the thiourea, which uses hydrogen bonding to make the edges of the shattered glass self-adhesive, according to Yanagisawa’s study.
But what use is all this if it cannot produce a self-healing smartphone screen?
“It is not realistically about fixing what is broken, more about making longer-lasting resin glass,” Yanagisawa told AFP.
Glass products can fracture after years of use due to physical stress and fatigue.
“When a material breaks, it has already had many tiny scars that have accumulated to result in major destruction,” Yanagisawa said.
“What this study showed was a path toward making a safe and long-lasting resin glass,” which is used in a wide range of everyday items.
“We may be able to double or triple the lifespan of something that currently lasts for 10 or 20 years,” he said.
Researchers accidentally engineer plastic-eating enzyme
- Despite recycling efforts, most plastic can persist for hundreds of years in the environment
- Researchers say they are now working on further improvements to the enzyme
TAMPA: Researchers in the US and Britain have accidentally engineered an enzyme which eats plastic and may eventually help solve the growing problem of plastic pollution, a study said Monday.
More than eight million tons of plastic are dumped into the world’s oceans every year, and concern is mounting over this petroleum-derived product’s toxic legacy on human health and the environment.
Despite recycling efforts, most plastic can persist for hundreds of years in the environment, so researchers are searching for better ways to eliminate it.
Scientists at the University of Portsmouth and the US Energy Department’s National Renewable Energy Laboratory decided to focus on a naturally occurring bacterium discovered in Japan a few years ago.
Japanese researchers believe the bacterium evolved fairly recently in a waste recycling center, since plastics were not invented until the 1940s.
Known as Ideonella sakaiensis, it appears to feed exclusively on a type of plastic known as polyethylene terephthalate (PET), used widely in plastic bottles.
The researchers’ goal was to understand how one of its enzymes — called PETase — worked, by figuring out its structure.
“But they ended up going a step further and accidentally engineered an enzyme which was even better at breaking down PET plastics,” said the report in the Proceedings of the National Academy of Sciences, a peer-reviewed US journal.
Using a super-powerful X-ray, 10 billion times brighter than the Sun, they were able to make an ultra-high-resolution three-dimensional model of the enzyme.
Scientists from the University of South Florida and the University of Campinas in Brazil did computer modeling which showed PETase looked similar to another enzyme, cutinase, found in fungus and bacteria.
One area of the PETase was a bit different, though, and researchers hypothesized that this was the part that allowed it to degrade man-made plastic.
So they mutated the PETase active site to make it more like cutinase, and unexpectedly found that this mutant enzyme was even better than the natural PETase at breaking down PET.
Researchers say they are now working on further improvements to the enzyme, with the hope of eventually scaling it up for industrial use in breaking down plastics.
“Serendipity often plays a significant role in fundamental scientific research, and our discovery here is no exception,” said study author John McGeehan, professor in the School of Biological Sciences at Portsmouth.
“Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics.”