Artificial Mother-of-Pearl Shines Like the Real Thing
A new, man-made rectangle of mother of pearl (right) looks similar to the natural material, made by shellfish (left).
CREDIT: Alex Finnemore, Univeristy of Cambridge
A new material inspired by the shiny lining of oyster shells could create a crack-resistant coating one day. The researchers who created the artificial mother-of-pearl say it is environmentally friendly and tougher than the oyster-made product. It also has an iridescent shine that's similar to real mother-of-pearl, they say.
Scientists have long studied how to replicate mother-of-pearl because it is lightweight, resists fractures better than many ceramics, and the materials that go into it are cheap, abundant and sustainable. This latest effort creates a man-made version of mother-of-pearl — also called nacre — by applying successive layers of chemicals in much the way an oyster would. The research teaches scientists more about how shellfish make nacre and creates a material that researchers could one day put into a tough, sustainable coating, the nacre's creators, a team of engineers from the University of Cambridge in the U.K., wrote in a paper published today (July 24) in the journal Nature Communications.
Naturally made nacre is made of microscopic plates of a hard mineral, called calcium carbonate, that are stacked and held together with a biological glue. The University of Cambridge engineers identified five steps that shellfish use to build nacre in thin, repeating layers. The researchers then tried to reproduce the steps by dipping a rectangle of glass into a series of liquid chemical mixes, letting the liquid harden between dips. Overall, the dipping process took five hours.
For the mineral layers, they used calcium carbonate, the same chemical that shellfish use. This is the first artificial mother-of-pearl made of calcium carbonate, the researchers wrote in their paper.
After they made pieces of their own nacre, the researchers broke them and examined the broken surfaces under a scanning electron microscope. They found the interior structure of their man-made mother-of-pearl was similar to natural nacre, they wrote in their paper. Tests also showed that the natural and artificial nacres had similar, though not identical, iridescent shines.