More commonly known as mother-of-pearl, nacre's combination of hardness and resilience has mystified scientists for more than 80 years. If humans could mimic it, it could lead to a new generation of ultra-strong synthetic materials for structures, surgical implants and countless other applications.
"We humans can make tougher materials using unnatural environments, for example extreme heat and pressure. But we can't replicate the kind of nano-engineering that mollusks have achieved. Combining the two approaches could lead to a spectacular new generation of materials, and this paper is a step in that direction," said Robert Hovden, U-M assistant professor of materials science and engineering.
Researchers - Basics - Nacre - Secret - Decades
Researchers have known the basics of nacre's secret for decades -- it's made of microscopic "bricks" of a mineral called aragonite, laced together with a "mortar" made of organic material. This bricks-and-mortar arrangement clearly lends strength, but nacre is far stronger than its materials suggest.
Hovden's team, which included U-M materials science graduate research assistant Jiseok Gim as well as geochemists from Australia's Macquarie University and elsewhere, worked together to crack the mystery.
U-M - Michigan - Center - Materials - Characterization
At U-M's Michigan Center for Materials Characterization, the researchers used tiny piezo-electric micro-indenters to exert force on shells of Pinna nobilis, commonly known as the noble pen shell, while they were under an electron microscope. They watched what happened in real time.
They found that the "bricks" are actually multisided tablets only a few hundred nanometers in size. Ordinarily, these tablets remain separate, arranged in layers...
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