Plastic foil electronic skin sensors
Ultra-lightweight electronics fashioned from thin plastic films that can be formed into sensors and microcircuits have been developed in Japan.
At just two microns thick, the plastic electronics are 50 times thinner than a human hair and 27 times lighter than paper. Dropped, they drift downwards more slowly than a feather.
They are also tolerant of being scrunched up into a tight ball, stretched to over twice their starting length, heating to over 170 degrees centigrade and immersion in salty water for a fortnight, all without any decrement in function.
The work is the brainchild of Tokyo University scientist Martin Kaltenbrunner and his colleagues who used relatively standard techniques to construct the devices.
The base layer comprises a foil made from a polymer called polyethylene naphthalate (PEN). Onto this, circuits are laid down using aluminium oxide and some small organic semiconductor molecules including one called DNTT (dinaphtho-thienothiophene).
Writing in Nature, where the work is published, the team describe the construction of a simple temperature probe and a tactile sensor.
They point out that the resilience of the material to repeatedly being deformed and its ability to conform smoothly to a range of surfaces including skin could make it ideal for monitoring and sensing applications on and inside the human body.
"Like plastic wrap," the team say, "they are easily applied to curvilinear and dynamic surfaces and can therefore be used in consumer appliances, architectural design, robotics, emergency response, sports, healthcare and biomedical systems."