Wallpaper speakers on the anvil

Washington, May 20 : Get ready for wallpaper doubling up as speakers, lightweight devices hunting for movement energy, and foldable speakers; for researchers in the US have designed a material having both physical and piezoelectric properties that may help in placing piezoelectric devices in previously impractical areas.

Usually microphones and speakers use piezoelectric materials that move in response to voltage, or create voltage from movement, however, these materials are expensive, heavy and brittle.

But materials scientist Michael Yu at Johns Hopkins University in Baltimore and colleagues, have made a breakthrough by designing a rubbery plastic-based material that may help these piezoelectric devices to be used in many other applications.

Based on polypropylene foam with piezoelectric properties that was discovered in 2004, this plastic is flexible and has entirely different mechanical properties to most other, often crystalline or ceramic, piezoelectric materials.

And now, it would be possible to control the material's piezoelectric mechanical properties, as the researchers have added silicone rubber to this material.

Till date, changing the flexibility of a piezoelectric material would result in disturbing its electrical properties. Thus, it was near-impossible to design materials with certain combinations of physical and piezoelectric properties.

However, including the ease with which polymers can be processed, the new material may pave the way for novel applications like wallpaper that functions as speakers, lightweight devices to scavenge movement energy, and foldable speakers.

ANI