Imagine having electronics that self-destruct once you no longer need them – that’s what a group of engineers has set out to accomplish. They’ve created devices that break down to their molecular components upon exposure to heat, which makes the material easier to recycle.
“We have demonstrated electronics that are there when you need them and gone when you don’t need them anymore,” said aerospace engineer Scott R. White. “This is a way of creating sustainability in the materials that are used in modern-day electronics. This was our first attempt to use an environmental stimulus to trigger destruction.”
White and his team collaborated on the device with John A. Rogers, a professor of materials science and engineering. The goal of the two teams was to make it easier for manufacturers to recycle materials from electronics and allow them to break down in landfills.
So how do their heat-triggered devices work? They use magnesium circuits, which are printed on a material that’s both thin and flexible. Extremely small droplets of a weak acid are dropped in wax, and the device is then coated in it. The wax melts when the device is heated, which in turn releases the acid and helps the device dissolve.
This reaction can be triggered remotely thanks to an embedded radio-frequency receiver and a heating coil in the device. In order for the coil to heat up (which causes the wax to melt), a user has to send a signal.
“This work demonstrates the extent to which clever chemistries can qualitatively expand the breadth of mechanisms in transience, and therefore the range of potential applications,” said Rogers.
By altering the concentration of the acid, the thickness of the wax and the temperature, the researchers are able to control the speed at which the device degrades. The researchers can destruct the device in anywhere from 20 seconds to a few minutes once heat is applied.
“We took our ideas in terms of materials regeneration and flipped it 180 degrees,” White said. “If you can’t keep using something, whether it’s obsolete or just doesn’t work anymore, we’d like to be able to bring it back to the building blocks of the material so you can recycle them when you’re done, or if you can’t recycle it, have it dissolve away and not sit around in landfills.”
A detailed account of White’s research was recently published in the journal Advanced Materials. For more information, visit the University of Illinois website.