Recycling Polystyrene Waste into Electromechanically Responsive Materials by Producing Multilayered Films from Bilayers with Asymmetric Triboelectric Properties

Millions of tons of foamed polystyrene (FPS) are produced annually. FPS is a major environmental problem. Polystyrene is slow to biodegrade, with an estimated decomposition time of up to 500 years. FPS contains 95% of air, and thus, it has a very low extent of recycling. According to a study by the California Integrated Waste Management Board, less than 1% of FPS was recycled in 2019. At the same time, FPS fills up 25% to 30% of landfill space by volume around the world.<br/>Here, we report the upcycling of FPS waste into electromechanically responsive triboelectric laminates (TLs). These TLs possess internal triboelectric dipoles offering an alternative to ferroelectric fluoropolymers. The piezoelectric contact-mode testing showing a FPS laminate is comparable to state-of-the-art piezoelectric fluoropolymers for overall electromechanical conversion. Piezoelectric fluoropolymers are critical electromechanically responsive materials for flexible energy harvesting and sensors. However, their production results in the release of significant amounts of toxic substances into the environment, and as such, these fluoropolymers are at risk of being banned by the European Union. Our alternative flexible electromechanically responsive materials can replace piezoelectric fluoropolymers, thus enabling rapid integration into current technology standards.