Building transient electronics is usually about doing something to make them stop working: blast them with light, soak them with acid, dunk them in water.
Professor Leon Bellan’s idea is to dissolve them with neglect: Stop applying heat, and they come apart.
Using silver nanowires embedded in a polymer that dissolves in water below 32 degrees Celsius — between body and room temperature — Bellan and mechanical engineering graduate student Xin Zhang made a simple circuit board that, so far, just turns on an LED light. Its potential applications are far more promising.
In the lab, his tiny circuit boards stay operational in water warmed by a hot plate. Turn off the hot plate, and they start dissolving in minutes.“Let’s say you use this technology to make an RFID wireless tag,” said Bellan, assistant professor of mechanical and biomedical engineering at Vanderbilt University. “You could implant important information in a person, and body temperature would keep it intact. If the tag were removed or the bearer died, it would dissolve. You could use it for implanted medical devices as well – to cause them to disintegrate, it would only require applying ice to the skin.”