Shock-absorbing and sound-absorbing materials such as rubber sheets and foam tend to be thick, large, and soft. However, a new type of material is different, absorbing vibration while remaining strong and thin. Often, if you want to build a structure that is both strong and durable and can absorb vibrations, you have to combine load-bearing rigid materials with softer substances. Another method is to install mechanical shock absorbers on the structure. In either case, the finished product will be heavier, bulkier, and more expensive than a product using only rigid materials. This is where new composite materials come in.

Samples of a glass-based material (the same weight as regular glass) are dropped to the ground for testing

The material, developed by Ioanna Tsimouri, Andrei Gusev and Walter Caseri at ETH Zurich's research institute, consists of ultra-thin stacks of rigid materials joined by thinner layers of elastic polymers. More specifically, the initial prototype consisted of a glass plate 0.2 to 0.3 millimeters thick and a layer of PDMS (polydimethylsiloxane) silicone a few hundred nanometers thick.

This ratio is important because computer models show that in order to achieve ideal properties, the composite must be at least 99 percent hard material (by volume) and less than 1 percent polymer. "If the polymer layer is too thin, the damping effect is minimal. If it is too thick, the material is not stiff enough," said Tsimouri, who led the research.

Samples of this material withstood standard three-point bending strength tests while also demonstrating excellent damping properties at temperatures of -125ºC (-193ºF).

In a demonstration of the properties of this composite material, which can be seen in the video below, thin sheets of the material and standard pieces of glass were dropped onto a table from a height of 25 cm (9.8 inches). The glass bounced into the air with a loud clicking sound, while the composite material didn't bounce and made a muffled sound.

Once the technology is further developed, versions could be used in areas such as windows, machine casings, car parts and even aerospace components. Additionally, because small amounts of PDMS break down into glass when melted, current glass-based composites can be fully recycled.

A paper on this research was recently published in the journal CompositesPartB:Engineering.