Tattoos as Wearable Electronics

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Similar to a child’s decorative tattoos, these electronic tattoos are a step forward in wearable circuits and computing systems

Researchers at Carnegie Mellon University have developed electronic tattoos that can help in the development of wearable computing systems. The tattoos are basically thin moldable circuits created using an off-the-shelf printer.

Construction and manufacturing

The construction of the moldable circuits is done by joining small amounts of an electrically conductive liquid metal alloy to a tattoo paper. This paper can be adhered to the human skin by applying small amounts of water. This process is similar to that of temporary decorative tattoos that children apply.

The technique uses a desktop inkjet printer to print traces of silver nanoparticles on temporary tattoo paper. The particles are then coated with a thin layer of gallium indium alloy in order to increase the electrical conductivity and make the printed circuit mechanically robust.

Scientists also suggested that the manufacturing process offers a simpler technique than those wearable electronics that are produced in cleanrooms.

Wiring solution to curvatures

The team approximated that the wiring can withstand strains up to 30 per cent which is roughly the flexibility of human skin. This property can allow the tattoo circuits to adhere to very curved 3D surfaces.

The team also practised the application of the tattoos on a human brain model and on a lemon. Given their bending properties similar to that of the human skin, electronic tattoos have potential applications in epidermal bio-monitoring, soft robotics, flexible displays, and 3D-transferable printed electronics.