Resilient, ultra-slippery glass could lead to self-cleaning, scratch-resistant windows, lenses, and solar panels
The new coating could be used to create durable, scratch-resistant lenses for eyeglasses, self-cleaning windows, improved solar panels and new medical diagnostic devices, said principal investigator Joanna Aizenberg, who is the Amy Smith Berylson Professor of Materials Science at the Harvard School of Engineering and Applied Sciences (SEAS), a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering, and Professor of Chemistry and Chemical Biology.
The new coating builds on an award-winning technology that Aizenberg and her team pioneered called Slippery Liquid-Infused Porous Surfaces (SLIPS)—the slipperiest synthetic surface known. The new coating is equally slippery, but much more durable and fully transparent. Together these advances solve longstanding challenges in creating commercially useful materials that repel almost everything.
SLIPS was inspired by the slick strategy of the carnivorous pitcher plant, which lures insects onto the ultraslippery surface of its leaves, where they slide to their doom. Unlike earlier water-repelling materials, SLIPS repels oil and sticky liquids like honey, and it resists ice formation and bacterial biofilms as well.
While SLIPS was an important advance, it was also “a proof of principle”—the first step toward a commercially valuable technology, said lead author Nicolas Vogel, a postdoctoral fellow in applied physics at SEAS.
“SLIPS repels both oily and aqueous liquids but it’s expensive to make and not transparent,” Vogel said.
The original SLIPS materials also need to be fastened somehow to existing surfaces, which is often not easy.
“It would be easier to take the existing surface and treat it in a certain way to make it slippery,” Vogel explained.
Vogel, Aizenberg, and their colleagues sought to develop a coating that accomplishes this and works as SLIPS does. SLIPS’ thin layer of liquid lubricant allows liquids to flow easily over the surface, much as a thin layer of water in an ice rink helps an ice skater glide. (See video.)
To create a SLIPS-like coating, the researchers corral a collection of tiny spherical particles of polystyrene, the main ingredient of Styrofoam, on a flat glass surface like a collection of Ping-Pong balls. They pour liquid glass on them until the balls are more than half buried in glass. After the glass solidifies, they burn away the beads, leaving a network of craters that resembles a honeycomb. They then coat that honeycomb with the same liquid lubricant used in SLIPS to create a tough but slippery coating.
“The honeycomb structure is what confers the mechanical stability to the new coating,” said Aizenberg.
By adjusting the width of the honeycomb cells to make them much smaller in diameter than the wavelength of visible light, the researchers kept the coating from reflecting light. This made a glass slide with the coating completely transparent.
These coated glass slides repelled a variety of liquids, just as SLIPS does, including water, octane, wine, olive oil and ketchup. And, like SLIPS, the coating reduced the adhesion of ice to a glass slide by 99 percent. Keeping materials frost-free is important, since adhered ice can take down power lines, decrease the energy efficiency of cooling systems, delay airplanes and lead buildings to collapse.
Importantly, the honeycomb structure of the SLIPS coating on the glass slides confers unmatched mechanical robustness. It withstood damage and remained slippery after various treatments that can scratch and compromise ordinary glass surfaces and other popular liquid-repellent materials, including touching, peeling off a piece of tape, and wiping with a tissue.
The Latest on: Ultraslippery glass
- Sports sedan from Toyotaon July 8, 2017 at 5:31 pm
For 1985, the Japanese carmaker has gone to flush-mounted headlights and side glass. Yet even with the ... is hardly competitive with many of the ultra-slippery cars of today.
- The greatest concept cars of 2017 so faron June 1, 2017 at 4:11 am
The ultra-slippery EV can lean into corners and offers ... These include the V-shaped grille along with the floating roof – a glass panel supported by blacked-out pillars. MG E-MOTION: We ...
- Xiaomi Redmi 4: Our First Impressionson May 18, 2017 at 9:48 am
The latest in the slew of smartphones making their way into the Indian market is the Xiaomi Redmi 4 ... typical Redmi design element like the ultra-slippery surface are not to be seen on this ...
- Review: Xiaomi Mi MIXon November 16, 2016 at 4:00 pm
For reference Diamond is 10 MoH, the hardest of minerals, while sapphire is just a notch down at 9 MoH, and the latest Gorilla Glass is around ... small drop of this ultra slippery ceramic phone ...
- Travel: Cruising into a Greek Odysseyon May 26, 2016 at 5:00 pm
Meanwhile there’s an outdoor swimming pool, another smaller one inside with a retractable glass roof, four large whirlpools ... climbed into the high 20s while descending those ultra-slippery marble ...
- This impossibly thin iPhone 6 case is just $15 on Amazonon March 4, 2015 at 4:00 pm
Apple says the housings on its iPhone 6 and iPhone 6 Plus are made out of aluminum, but we think it’s actually some sort of ultra-slippery compound ... like frosted glass, and wisp black.
- Super-Slippery Coating Inspired by Carnivorous Planton September 24, 2013 at 5:00 pm
SLIPS was originally inspired by the carnivorous pitcher plant, coated with an ultra-slippery surface that slides insect victims ... completely transparent coating that can turn regular glass into a ...
- New coating turns ordinary glass into super glasson August 2, 2013 at 11:17 am
August 2, 2013 - A new transparent, bioinspired coating makes ordinary glass tough ... which lures insects onto the ultraslippery surface of its leaves, where they slide to their doom.
- Better Nature: Technologies Inspired by the Natural Worldon March 21, 2013 at 5:00 pm
Inside the Boston headquarters of Harvard University’s Wyss Institute for Biologically Inspired Engineering, an exuberant Don Ingber weaves through a maze of chlorine-scented laboratories, ...
- New coating prevents more than 99 percent of harmful bacterial slime from forming on surfaceson July 29, 2012 at 4:59 pm
Biofilms stick to just about everything, from copper pipes to steel ship hulls to glass catheters. The slimy coatings are more than just a nuisance, resulting in decreased energy efficiency ...
via Google News and Bing News