A research team from University of Houston and China has developed a new type of electronic device that can be triggered to dissolve when it is exposed to water.
This discovery has the potential for eco-friendly disposable personal electronics and biomedical devices that dissolve in the body. There could also be defensive applications for the dissolvable electronics. This includes devices that can be programmed to dissolve in order to keep sensitive information safe. Cunjiang Yu, Bill D. Cook assistant professor of mechanical engineering at the University of Houston, led the research.
The field, called physically transient electronics, currently requires immersion in aqueous corrosive solutions or biofluids. This work demonstrates a new working mechanism – the dissolution is triggered by ambient moisture.
"More importantly, the transient period of time can be precisely controlled," said Yu.
This could mean that a biomedical implant could be programmed to disappear when its task is complete, like when it is finished administering medication. Sensitive communications could be devised to vanish after the message is delivered. New versions of cell phones could be programmed to dissolve when they are no longer in use, instead of sitting around in people’s kitchen drawers.
"We demonstrate that polymeric substrates with novel degradation kinetics and associated transience chemistry offer a feasible strategy to construct physically transient electronics," the researchers wrote. "Through the manipulation of the polymer component and environmental humidity, the progress of hydrolyzing polyanhydrides can be managed and thus the dissolution kinetics of (a) functional device can be controlled."
The time period the electronics can last ranges from days to weeks or even longer if needed. The lifespan of these devices is controlled by varying the humidity level or by changing the polymer composition.
Functional electronics components were built through an additive process onto a film that is made of polymer polyanhydride. The device remains stable until ambient moisture triggers the chemical breakdown that digests the inorganic electronic materials and components. The researchers tested many compounds, including aluminum, copper, nickel indium-gallium, zinc oxide and magnesium oxide. They then developed various electronic devices, like resistors, capacitors, antennas, transistors, diodes, photo sensors and more in order to demonstrate the model's versatility.
A paper on this new discovery was published in Science Advances.