Nacre, also known as mother-of-pearl, makes up the outer coating of pearls. It can also be found on the inner shell layer of some molluscs. It’s strong, resilient, and iridescent--it gradually changes color depending on the angle that you view it.
Now, a research from the University of Connecticut in Storrs made a flame-resistant, strong and airtight polymer coating with respect to how this colorful mother-of-pearl looks. And I tell you, it wasn't the most pleasant process.
To make the thin coating, the researchers mixed a type of clay (that creates layers when exposed to ultrasonic pulses) with water and a polymer to hold the everything together. Next, they dipped strips of plastic in the clay-polymer mixture to coat them. When the coated sheets are hung, the liquid layer flows downwards to the ground, pulling the sheets of clay to aligning with one another like bricks. This makes the coating strong and airtight. Lastly, the coating is then baked in an oven, drying the polymer within the coating. Painstaking as it may seem, the whole process can actually be done in just a matter of minutes!
Researchers were able to make their film coating 60 percent stronger than stainless steel. The material was over 13,000 times more airtight to air and other gasses than the plastic sheet that was used. And when the researchers set it on fire, it scorched but didn’t catch fire.
“Traditionally people make this kind of material very tiny, fingernail-sized, and it would take maybe a week to coat a small object like this,” says Luyi Sun from the University of Connecticut. “Now we can do it easily on standard-sized paper in minutes.”
Not only is the whole process fast, its components are environmentally friendly as well. It can be easily applied to any object that requires an airtight or a fireproof coating.
“Some biodegradable plastics have a bunch of bad properties – they have a poor barrier and they’re flammable,” says Jaime Grunlan at Texas A&M University in College Station who wasn’t involved with the study. “With this coating, they could compete with higher-performance polymers.”
Get weekly science updates in your inbox!