Materials and processes for ultrathin stick-on electronic devices using elastomeric “nanosheet” film have been developed by a group of researchers at Waseda University. With these new developments, they have enabled ease of production while at the same time preserving high flexibility and elasticity estimated to be fifty times better than previously reported polymer nanosheets.
Wearable devices and smart electronics require ease of fabrication and wearing comfort for widespread adoption. The Waseda University team’s processes and materials represent massive strides forward in both requirements.
Production of electronic devices that are not only extremely thin and flexible, but also functional and durable, has been enabled by inkjet printing of circuitry and low-temperature fixing. The devices can be used as a comfortable, skin-fitting appliance, while at the same time upholding the protection and easy handling properties of elastomeric films. The new film is flexible and ultra-thin at only 750 nm. These improvements could help change the nature of wearable electronics from items like wristwatches to objects that are less noticeable than a plaster.
The Waseda team also pioneered a method of joining electronic components that does not require soldering. This allows for elastomer films that are more flexible and thinner. Conductive “wiring” is created by printing with a normal household type inkjet printer without the need for clean room conditions. Elements such as LEDs and chips are connected to the conductive lines by adhesive sandwiching between two elastomeric nanosheets. This does not require any chemical bonding normally achieved by special conductive adhesives or soldering.
Due to the low-temperature, simple processes, the ultrathin structures produced achieve better comfort and elasticity for skin contact applications, and better adhesion, without using adhesive components such as glue or tape. The new system was tested for several days on an artificial skin model and proved functional.
Possible applications for these products include human-machine sensors and interfaces in the shape of electronic tattoos, and as radically improved tools for the fields of sports training, healthcare and medicine.
The full peer reviewed study was published in the Journal of Materials Chemistry C.