Sound and vibration proofing is a crucial aspect in the designing of buildings, aircraft, and cars, as it can significantly improve the comfort of settlers or passengers. Manufacturers use all sorts of materials to reduce unwanted noise, including mass-loaded vinyl, acoustic foam, butyl rubber, polyurethane foam, etc.
However, these materials share a common theme — they are soft and bulky. Also, they can’t be used as stressed members and must be paired with a stiffer material, like metal. This adds complexity to manufacturing, adds unnecessary weight, and raises the price of the finished product.
However, that could soon change. A new study by researchers at the ETH Zurich Institute demonstrated a stiff and thin material with excellent sound-proofing and dampening properties. Curiously, the researchers used multiple layers of ultra-thin glass, bound by an elastic polymer. The glass needs to be very thin, at around 0.2 to 0.3 mm, while the PDMS (polydimethylsiloxane) silicone is only a few hundred nanometers thick.
Using computer simulations, the team found that a ratio of 99% glass and less than 1% polymer has the best dampening properties while remaining stiff. Crucially, the material could dampen vibrations and noise successfully down to -125 °C (-193 °F), while also being strong enough to withstand the standard three-point bending strength tests. It’s easily recyclable, too. Melting the material will cause the PDMS to decompose into glass, making it a sustainable solution.
The team uploaded a video on ETH Zurich’s YouTube channel, where two small sheets of regular glass and the new glass-polymer composite were dropped from a height of 25 cm (9.85 inches). The excellent dampening properties of the composite are clearly evident; the sheet produced less noise, and there was hardly any bounce.
Thanks to its excellent properties, the new glass-polymer composite could find its way into multiple industries. Windows made from this transparent material could provide excellent soundproofing and dampening while remaining relatively thin and lightweight. The automotive and aerospace industries can also use it to produce various parts, too. Good examples would be motor, compressor, or transmission housings, where the composite could minimize vibrations and unwanted noise, while also serving as a stressed member.
