Electronic sensors made using liquids can outperform other flexible devices that have solid components.

Most sensors rely on solid metals that form junctions. To render such devices flexible, Ali Javey of the University of California, Berkeley, and his colleagues developed a way to make a junction between two different fluids that does not allow them to mix.

For the junction, the team fabricated a series of microchannels, each about 30 micrometres wide, which are designed to let in only one of the fluids — an ionic liquid. The other fluid, the commercial liquid metal Galinstan, has too much surface tension to enter the channels.

The sensors could detect humidity, oxygen and temperature; the temperature sensor was 17–46 times more sensitive than flexible alternatives made with solid components. The device could be useful in prostheses, robotics and smart wallpapers, the authors say.

Nature Commun. 5, 5032 (2014)