Tough, Flexible Material Could Protect Soldiers & Astronauts

March 12, 2015
Kevin Hattori

A team of researchers has developed a revolutionary material that has superior anti-penetration properties while remaining flexible. Inspired by the way nature designed fish scales, the material could be used to make bulletproof clothing for the military and space suits that are impervious to micro-meteorites and radiation when astronauts embark on spacewalks. The joint research was conducted at the Technion-Israel Institute of Technology and the Massachusetts Institute of Technology.

“The secret behind this material is in the combination and design of hard scales above with soft, flexible tissue below,” says Technion Assistant Professor Stephan Rudykh, pictured here.

A paper outlining the characteristics, test results and applications of the new material was published online on February 20 by the technology journal Soft Matter, a publication of the Royal Society of Chemistry. The research was led by Assistant Professor Stephan Rudykh, head of the Technion’s Mechanics of Soft Materials Laboratory.

“Many species of fish are flexible, but they are also protected by hard scales,” said Prof. Rudykh. “Taking inspiration from nature, we tried to replicate this protecto-flexibility by combining two layers of materials – one soft for flexibility and the other with armor-like scales. The secret behind this material is in the combination and design of hard scales above with soft, flexible tissue below.”

Generally, strength and flexibility are competing properties, explained Prof. Rudykh. You can’t have both. However, the research team found a way to increase the penetration resistance by a factor of 40, while the flexibility of the soft material was reduced by only a factor of five. If the application is, for example, a military uniform for combat, more flexibility can be built into the areas needing flexibility, such as the elbows and knees, while the anti-penetration properties elsewhere, such as in the upper body, can be beefed-up.

“That attribute allows for the fabric to be tailored to the wearer’s body and the environment that the wearer will be facing,” explained Prof. Rudykh, who carried out post-doctoral studies at MIT where he worked with 3-D printing technology before joining the Technion. “This work is part of a revolution in materials properties. Once we can gain control over a material’s micro properties, using 3-D printing we can create materials of an entirely different type, each with the ability to be adjusted to fit the wearer, the need, and the environment.”

The researchers have conducted initial testing on the material and are moving into dynamic tests using fast-moving projectiles, both bullets and small particles, and also testing the flexibility attribute under pressure.

“Our findings provide new guidelines for developing simple material architectures that retain flexibility while offering protection with highly tunable properties,” concluded the researchers. “The tailored performance of the protective system – with characteristics that can be tuned according to the required movements at different regions of the body – draws its abilities from the microstructural geometry. The ability for a given microstructure to offer different deformation resistance mechanisms is key to achieving the multifunctional design of stiff plates and soft matrix. We found that careful selection of microstructural characteristics can provide designs optimized for protection against penetration while preserving flexibility.”

This research was supported by the U.S. Army Research Office through the MIT Institute for Soldier Nanotechnologies under contract W911NF-13-D-0001. CO gratefully acknowledges the support of the National Security Science and Engineering Faculty Fellowship Program (no. 0244-09-1-0064). SR acknowledges the support of Taub Foundation through the Horev Fellowship – Leaders in Science and Technology.

The Technion-Israel Institute of Technology is a major source of the innovation and brainpower that drives the Israeli economy, and a key to Israel’s renown as the world’s “Start-Up Nation.” Its three Nobel Prize winners exemplify academic excellence. Technion people, ideas and inventions make immeasurable contributions to the world including life-saving medicine, sustainable energy, computer science, water conservation and nanotechnology. The Joan and Irwin Jacobs Technion-Cornell Institute is a vital component of Cornell Tech, and a model for graduate applied science education that is expected to transform New York City’s economy.

American Technion Society (ATS) donors provide critical support for the Technion—more than $2 billion since its inception in 1940. Based in New York City, the ATS and its network of supporters across the U.S. provide funds for scholarships, fellowships, faculty recruitment and chairs, research, buildings, laboratories, classrooms and dormitories, and more.