Degradable materials are emerging as a solution to the fast-growing issue of electronic waste, enabling the recycling of components from various single-use and wearable devices.
Credits:Credit: Christine Daniloff, MIT; iStock
Electronic waste is a rapidly growing global problem, expected to worsen with the production of new flexible electronics for various applications, including single-use devices. A new flexible substrate material developed at MIT, the University of Utah, and Meta enables the recycling of materials and components at the end of a device’s life and facilitates the scalable manufacture of more complex multilayered circuits.
Most research has focused on entirely different polymer materials, but this approach overlooks the commercial reasons behind the initial choice of materials, explains Wallin. Kapton, for example, is widely used due to its excellent thermal and insulating properties and the ready availability of its source materials. Due to its high heat tolerance, the polyamide market, projected to reach $4 billion globally by 2030, is pervasive in electronic devices, including flexible cables in cellphones and laptops and in aerospace applications.
Despite its advantages, Kapton cannot be melted or dissolved, making reprocessing impossible and complicating the manufacture of advanced multilayered electronics. Traditional Kapton production requires heating to 200-300 degrees Celsius, a slow process taking hours, according to Wang.
The team developed an alternative polyimide-based material compatible with existing manufacturing infrastructure. This light-cured polymer, akin to dental materials that harden quickly under ultraviolet light, cures rapidly at room temperature. This new material could serve as a substrate for multilayered circuits, significantly increasing the number of components in a small form factor.
Unlike Kapton, which requires layers to be glued together, adding steps and costs, the new material can be processed at low temperatures and hardens quickly on demand, creating new multilayer devices.
For recyclability, the team incorporated subunits into the polymer backbone that can be quickly dissolved by an alcohol and catalyst solution, allowing for the recovery and reuse of precious metals and entire microchips from the solution for new devices.
