Globalization and Policy Diffusion: Explaining Three Decades of Liberalization

We report the development of low-cost triboelectric nanogenerators (TENGs) based on polypropylene (PP) fabrics formulated via an inexpensive melt-blowing process with an output voltage as high as 50 V. By disinfection methods such as exposure to steam, ethanol, and dry heat at 75 °C, the commercial medical masks and N95 filtering facepiece respirators (FFRs) can be reused to fabricate PP fiber based TENGs, which provide a novel regime for energy-harvesting devices based on reusable materials. As a power source, the output of one TENG can drive 15 serially connected light-emitting diodes (LEDs) or a commercial electric calculator. PP fabric TENGs can also work as self-powered sensors for the high-sensitivity detection of mechanical impact. We provide examples where the TENG is used to detect biomechanical motion such as that associated with the extension of an elbow, the touch of a finger, the impact of footsteps, and the bending of a knee without an external power supply. Most importantly, these PP fabrics for TENGs can be obtained from decontaminated medical masks that are generated as tremendous wastes every day, which provide a great potential as sustainable energy. These properties suggest that PP fabric based TENGs are promising for harvesting energy from biological systems and that they may facilitate the large-scale production of a new range of inexpensive self-powered multifunctional wearable sensors for applications in healthcare, security, and information networks.