Wearable strain sensor and flexible direct-current nanogenerator made by medical mask wastes and PEDOT:PSS-based conductive inks

The disposal of polypropylene (PP) from discarded masks during the COVID-19 pandemic has become a major source of plastic particle pollution in aquatic environments, such as rivers and estuaries, drawing significant attention from the healthcare industry. Converting these waste polymers into high-value electronic products offers an economically viable and sustainable solution, paving the way for innovative methodologies. The practical application of direct-current triboelectric nanogenerators (DC-TENGs) requires a precisely matched metal-semiconductor interface. Additionally, wearable sensors must be designed with flexibility and comfortability to ensure reliable performance in personal health monitoring and human-machine interaction. In this study, we use a simple drop-casting method to deposit a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based hybrid conductive layer onto a PP substrate derived from discarded masks. This enables the fabrication of flexible strain sensors and textile-based DC-TENGs. Our environmentally friendly approach aligns with several Sustainable Development Goals (SDGs), particularly SDG 12, which promotes responsible consumption and production.