Applications of Dissolvable Electronics
The market of dissolvable electronics may not sound very familiar to many and, honestly, that is because the market hasn’t been around for very long. The avenues for dissolving electronics aren’t very numerous, but it does have its niche.
The most familiar use of the technology is the ability for electronics to dissolve after being implanted into a person for medical purposes. Recently, however, there has been vested interest into data security and eco-friendliness as well.
There are currently devices out in the market that have dissolvable properties. The issue is that the circumstances behind the devices' dissolution inhibit the control we have over when the process happens. Typically these devices dissolve in a solution or after being exposed to a chemical, which we have little control over due to the degradation processes.
Recently, a research article published in the journal Science Advances describes a new moisture triggered physically transient device that has tunable degradation under the presence of moisture. The research team consisted of members from the University of Houston as well as contributing engineers from China.
Left to right: Xu Wang (co-author), Cunjiang Yu (Bill D. Cook Assistant Professor of mechanical engineering), and Kyoseung Sim (co-author). Image courtesy of the University of Houston
Moisture-Triggered Physically Transient Electronics
The new electronic, composed of a polyanhydride mixture, is capable of dissolving itself after being exposed to moisture in the atmosphere. Not only that, but the transient state can be precisely controlled, meaning that the dissolution can be triggered after a certain a desired event. This can be especially important in medicine, where an electronic device could be dissolved after delivering medication.
Figures A and B are a schematic illustration of the process. Figures C and D are actual optical images of the process occurring. Image from Science Advances
The electronic components of the device were created through additive processes that were layered onto a polyanhydride film and then dissolved as ambient moisture triggered the formation of acids. The triggered transient process begins as the polyanhydride substrate hydrologizes in the presence of moisture in the air.
The moisture triggers the substrate form into a corrosive acid that can be used to dissolve a myriad of metals and inorganic materials. This process is unique in nature in that polyanhydride is the only polymer that experiences surface erosion, which in turn allows the internal components to operate until the corrosion penetrates the tunable polyanhydride surface.
By changing the composition of the polyanhydride substrate, as well as the moisture levels, the transience of the device can be tuned to last from minutes to weeks. This property specifically allows for broadened applications in implants, data secure-hardware systems, and eco-friendly degradable devices.
The research was tested on a variety of different metals and metal compounds including nickel, copper, aluminum, zinc oxide, magnesium oxide, as well as fully constructed electronic devices to showcase the polymer's abilities.
According to the paper: “With the successful demonstration of various transient devices, ranging from passive components to active electronics, and an integrated system demonstration, we expect that this triggered transient mode can be applicable for future transient electronic systems, which may include a combined set of integrated circuit, sensors, data storage, signal transmission, etc.”
While it's unlikely that dissolvable electronics will meaningfully make their way into consumer-end products (at least, not anytime soon), there are myriad applications where this research could be pivotal for advancement.
Featured image used courtesy of the University of Illinois via NPR.