Science & Technology (Commonwealth Union) – Electronic waste, or e-waste, is an escalating issue across the world that is expected to intensify with the rise of new flexible electronics used in robotics, wearables, health monitors, and various single-use devices. Many researchers and governments across the world have recognized this problem with focus research to eliminate the growing global issue and some countries have even provided incentives to dispose e-waste in an environmentally friendly manner.
Researchers from the University of Utah, MIT and Meta innovate a new flexible substrate material that promises to facilitate both the recycling of materials and components at the end of a device’s lifespan, as well as the scalable production of more intricate multilayered circuits compared to current substrates.
This breakthrough is detailed in a recent paper published in RSC: Applied Polymers by MIT Professor Thomas J. Wallin, University of Utah Professor Chen Wang, and seven other contributors.
Professor Wallin, from MIT’s Department of Materials Science and Engineering, stated that they are aware that electronic waste is a persistent global challenge that will likely worsen as we continue to create more devices for the internet of things and as global development progresses. He further stated that much of the existing research in this area has focused on alternatives to traditional substrates for flexible electronics, which typically use Kapton, a trade name for polyimide.
Most research to date has concentrated on different polymer materials, but, as Wallin points out, it really overlooks the commercial aspects, such as why certain materials were originally chosen. He indicated that Kapton, for instance, offers notable benefits, including superior thermal and insulating properties and the ready availability of its raw materials.
The polyimide sector is expected to reach a $4 billion global market by 2030. Wang pointed out that it is found everywhere, in virtually every electronic device and its use in flexible cables that connect various components within devices like cellphones and laptops. He further pointed out that it is also extensively utilized in aerospace due to its exceptional heat resistance and while it is a classic material, it hasn’t been updated in three or four decades.
Researchers of the study pointed out nevertheless, that Kapton is extremely difficult to melt or dissolve, making reprocessing nearly impossible. Its properties also complicate the manufacturing of advanced circuit architectures, such as multilayered electronics. Wang further indicated that that the conventional method of producing Kapton requires heating the material to temperatures between 200 and 300 degrees Celsius, a process that is quite slow and takes several hours.
In contrast, the new material’s ability shows promise. This was developed by the team, which is a type of polyimide and thus compatible with existing manufacturing processes, is a light-cured polymer. This is similar to the materials used by dentists for durable fillings that cure quickly with ultraviolet light. Not only is this curing process much faster, but it also operates at room temperature.
Regarding recyclability, the team integrated subunits into the polymer backbone that can be quickly dissolved using an alcohol and catalyst solution. This process allows for the recovery of precious metals from the circuits and entire microchips, which can then be reused in the production of new devices.
“We break the polymer back into its original small molecules. Then we can collect the expensive electronic components and reuse them,” says Wallin. “We all know about the supply chain shortage with chips and some materials. The rare earth minerals that are in those components are highly valuable. And so we think that there’s a huge economic incentive now, as well as an environmental one, to make these processes for the recapture of these components.”
The ability of fighting e-waste with a new flexible substrate material by exploring different polymer materials or any material to tackle e waste that is only set to increase with wider reach, is the need of the hour.
