This nanomembrane can act like a mic or loudspeaker that plays music off your skin

Thin and versatile nanomembranes have been around for years now. However, this hasn’t combined the best of both qualities without compromising flexibility. A group of researchers from Ulsan National Institute of Science and Technology have engineered a remarkable versatile new hybrid nanomembrane. It is a combination of pure polymer membrane with dynamic electrical and mechanical components. The nanomembrane is thin, stretchable and imperceptible, and can be easily attached to the skin or nearly any other surface. The hybrid membrane was made using a polymer matrix carrying an array of orthogonally positioned nanowires made from silver. Silver nanowires also have excellent electrical properties and are capable of withstanding greater force and pressure compared to others, Interesting Engineering reports. [caption id=“attachment_5215631” align=“alignnone” width=“1280”] The hybrid nanomembrane was light, conductive and durable. It could act as a speaker and a voice recorder depending on how it was designed. Image courtesy: Science AAAS[/caption] In a recent study published in Science Advances, the highly conductive and transparent nanomembrane was tested in many different applications. One of its proof-of-concept experiments was turning the tiny membrane into a loudspeaker that could attach to nearly any surface. When the nanomembrane was fed with sound wave electrical currents, the membrane could emit sound waves. The researchers even went as far as demonstrating its use as a skin-attached loudspeaker that could be attached to the skin and play a part of a violin concerto— La Campanella by Niccolo Paganini.

The nanomembrane produces sound based on a principle called ‘Joule heating’. Current passing through the nanomembrane causes a temperature oscillation in it, producing a thermo-acoustic vibration. This vibration moves air in the region around the nanomembrane, which we hear as sound. The second proof of concept was the reverse of the first — use of the nanomembrane as a microphone. When electric signals were fed to the membrane, it acted as a loudspeaker. The very same nanostructures could also convert vibrations from sound signals in the environment into electric signals for a microphone. The nanomembrane could do more than record these sounds and voices. It could distinguish between voices from different people — well enough to go into voice-based security features, the study says. The thin transparent film, however, is already stronger than polymers of the same dimensions. It could find a central place in nanomembrane-based acoustic devices: IoT sensors and medical devices that work in concert with human senses, researchers reported.