Researchers may have found a new armor to protect US troops, inspired by seashells.
Their findings, described in Nature Materials, suggest mollusk shells of Placuna placenta evolved a nanostructure that allows light to pass through, yet also so strong no penetration damage could crack it. Such a trait would prove useful against predators.
For people, this scientific understanding could help improve synthetic materials, such as armor.
“We have long studied natural exoskeletons as inspiration for the development of advanced engineered protective systems,” said study author Christine Ortiz, a materials scientist at the Massachusetts Institute of Technology.
Ortiz and her colleague Ling Li investigated the windowpane oyster, Placuna placenta. They were especially interested in this mollusk, because it has a shell that permits 80 percent of visible light to shine through it.
“About five years ago we started searching for natural armor systems, which were also optically clear,” Ortiz said. Transparent armor could serve in “soldier eye or face protection, windows and windshields, blast shields and combat vehicles,” she said.
Engineered ceramic-based armor, while designed to resist penetration, often lacks the ability to withstand multiple blows, due to large-scale deformation and fracture that can compromise its structural integrity, Ortiz says.
Scientists have examined mollusk and other shells in the past, but “this is the first thorough study of a natural armor that resists mechanical penetration but is also optically clear,” Ortiz told Live Science. “We wanted to find out how the material resists penetration but also preserves this unique optical property.”
“It is an excellent and elegant piece of work. It successfully demonstrates the effectiveness of nanoscale deformation twins in energy dissipation in bioceramics, and should be able to inspire and guide the development of man-made ceramic materials,” Huajian Gao, a professor of engineering at Brown University who was not involved in the research, told MIT News.
“As a first-of-its-kind [demonstration of] the effectiveness of deformation twins in natural materials, this work should have huge practical impact,” Gao said.
“The work was supported by the National Science Foundation; the U.S. Army Research Office through the MIT Institute for Soldier Nanotechnologies; the National Security Science and Engineering Faculty Fellowships Program; and the Office of the Assistant Secretary of Defense for Research and Engineering,” MIT News reported.