Nature Mater. doi:10.1038/nmat2834; (2010); Nature Mater. doi:10.1038/nmat2835 (2010)

Artificial skins have been developed that can detect the gentlest of touches of just a few kilopascals or less in pressure, the same as that felt by our fingers when typing, or picking up a pen.

Zhenan Bao at Stanford University, California, and her colleagues built a pressure sensor using the elastic polymer polydimethylsiloxane (PDMS). They engineered the material such that its capacitance — the ability to hold an electric charge — changed when pressure was applied to it. The researchers then attached this capacitor to a grid of organic transistors so that it could track pressure changes at specific positions. Their device could sense the presence of a fly and a butterfly (pictured).

Ali Javey at the University of California, Berkeley, and his team used a different approach. They laid out parallel arrays of semiconducting nanowires on a flexible pressure-sensitive rubber. Both 'skins' could eventually be used in prosthetics or touch-sensitive robotic devices.

Credit: L. CICERO, STANFORD UNIV.