From an article at nanotech.now:

In research appearing online in the journal Advanced Materials Interfaces, graduate student Peter Owuor, research scientist Chandra Sekhar Tiwary and colleagues from the laboratories of Rice Professor Pulickel Ajayan and Jun Lou found they could increase the stiffness, or “elastic modulus,” of a soft silicon-based polymer by infusing it with tiny pockets of liquid gallium.

Such composites could find use in high-energy absorption materials and shock absorbers and in biomimetic structures like artificial intervertebral discs, they said.

Owuor said conventional wisdom in composite design for the past 60 years has been that adding a harder substance increases modulus and adding a softer one decreases modulus. In most instances, that’s correct.

“People had not really looked at it from the other way around,” he said. “Is it possible to add something soft inside something else that is also soft and get something that has a higher modulus? If you look at the natural world, there are plenty of examples where you find exactly that. As materials scientists, we wanted to study this, not from a biological perspective but rather from a mechanical one.”

For example, the discs between the vertebrae in human spines, which act like both shock absorbers and ligaments, are made of a tough outer layer of cartilage and a soft, jelly-like interior. And the outer skin of deep-diving ocean fish and mammals contain myriad tiny oil-filled chambers — some no larger than a virus and others larger than entire cells — that allow the animals to withstand the intense pressures that exist thousands of feet below the ocean’s surface.

 

Read more at nanotech.now
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Image Credit:   Jeff Fitlow/Rice University

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