Clemens Valens

Remote controlled vaporisable electronics

February 13, 2018 | 12:28
Photo: Cornell University
Photo: Cornell University
Transient electronics are devices that disintegrate when they are no longer needed. Medical implants are a field of applications for such technologies. A device containing medication is implanted in the patient’s body, and when the treatment is finished, instead of removing the implant through surgical operation, the device simply dissolves.

Several techniques exist, like dissolvable electronics or by using heat, but they have the inconvenience that the moment of disintegration is not precisely controlled. Should the device melt away when it rains or not?

Researchers from Cornell University (USA) have come up with a new method where the device’s self-destruction is triggered after receiving a radio signal. The trick consists of embedding the circuit in a polycarbonate shell together with tiny cavities filled with metals such as rubidium and caesium. When these metals are liberated, they react with oxygen and destroy the circuit.

The metals are held behind graphene and silicon nitride membranes. To liberate them, in response to a radio signal the device passes a current through the membrane. Now the graphene heats up until it cracks the silicon nitride which in turn allows air to react with the metals. The heat produced by the resulting chemical reaction finally destroys the device.

After disintegration a fine powder made of caesium and rubidium oxides is left, together with sand from the silicon chip, tiny flakes of carbon from the graphene, and the battery.

Photo: Cornell University
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