A semitransparent snake-like tactile and olfactory bionic sensor with reversibly stretchable properties

A wearable sensor can track full-range human motion and sniff out toxic gases using polymer nanowires with features similar to snakeskin. The device, which was developed by Pooi See Lee and co-workers at Nanyang Technological University, is based on polyaniline, a conducting polymer with natural flexibility and chemical sensitivity. Polyaniline often becomes unworkably rigid when deposited as a thin film, but the Singapore-based team avoided this issue by growing a vertical forest of polymer nanowires on a thin silicone support. Scanning electron microscopy revealed that when stretched, the nanowires formed scale-like islands and cracks that alter the resistance of the thin film. The researchers demonstrated that these electrical changes were sensitive enough to use for forehead sensors of breathing and eye movement and as a ‘smelling skin’ for detecting methane–an odorless and explosive gas.