This circuit board self-destructs once it’s cooled; here’s why

By Nicole DiGiose, content editor

When developing transient electronics — devices that self-destruct by design — an important factor is figuring out how to stop them from working, whether that means dipping them in water or blasting them with light. And although the idea of a circuit board dissolving once it’s cooled sounds like something from “James Bond,” a groundbreaking study under way at Vanderbilt University suggests that such a board is not just possible but practical.

As described in a paper published in the journal ACS Applied Materials and Interfaces, the researchers have been working on a way to build transient electronics that come apart when you stop heating them.

Nanowires are embedded in the polymer, which holds the network in place so they touch one another, producing a path to conduct electricity. Image source: Vanderbilt University’s YouTube channel.

“What we have done is produce a composite system that behaves like a regular circuit board when immersed in warm water, but if the water cools below a threshold temperature, the entire system disintegrates, dissolves, and stops working,” Dr. Leon Bellan, assistant professor of mechanical and biomedical engineering at Vanderbilt, told Digital Trends. “We have achieved this behavior by coupling two separate materials: networks of silver nanowires and a polymer that exhibits the odd behavior of being insoluble in warm water, but soluble in cold water.”

The nanowires are embedded in the polymer, which holds the network in place so they touch one another, producing a path to conduct electricity. If the polymer is dissolved, there’s nothing to hold the nanowires together. As a result, the network and nanowires fall apart, and the conductive path is lost as the entire system disintegrates.

Check out the video by Vanderbilt University below to see this technology in action.

Why would you want a dissolving circuit board? One obvious application is covert operations. The heat supply could be a battery powering a heater, or even the body temperature of a soldier who’s been implanted with a top-secret circuit. If the battery goes missing or the body heat is no longer available, the circuit disappears.

According to Bellan, other possible applications include tracking tags that would be implanted in hospital patients. Local application of a cooling stimulus could trigger the implanted tag to disintegrate and stop functioning so that it would not have to be surgically removed.

Although such technology sounds futuristic, it’s on its way to becoming a reality. The next steps for the Vanderbilt researchers include integrating semiconductors to make transistors and ensuring that users can interact wirelessly with the device.