Sustainable Poly(ethylene furanoate)/Recycled PET Electrospun Blend Membranes for Human-Motion Triboelectric Energy Harvesting

Abstract

Triboelectric nanogenerators (TENGs) using bio-based or recycled-polymer tribolayers offer a sustainable approach to energy harvesting. This work reports TENGs comprising electrospun nanofibrous membrane (ENM) tribolayers produced from bio-based poly(ethylene furanoate) (PEF) and recycled poly(ethylene terephthalate) (rPET). All nanofibrous membranes showed bead-free and smooth fibrous morphology. The PEF ENM showed the smallest fiber diameter (230 ± 10 nm), whereas the PEF/rPET blend ENM exhibited an intermediate average fiber diameter of 244 ± 13 nm and the most uniform fiber distribution. Stabilizing intermolecular interactions within the PEF/rPET blend contributed to its chemical, thermal, and mechanical stability. The single, merged glass transition temperature (Tg) of the PEF/rPET membrane and the favorable miscibility parameter (Δδ ≤ 5 MPa1/2) supported substantial miscibility between the amorphous phases of the two polymers. Compared with rPET, the bio-based PEF TENG exhibited an 11-fold increase in peak-to-peak voltage, reaching 11.4 V at 100 N and 20 Hz. The optimized PEF/rPET ENM-based TENG produced the highest output of 33.8 V and 2.4 μA at 100 N and 20 Hz, achieved a maximum power density of approximately 140 mW/m2 at 10 MΩ, and effectively charged commercially available capacitors. The optimized TENG harvested energy from and detected various human motions, with a maximum peak-to-peak voltage of 400 V generated by finger tapping. Moreover, the voltage generated by the TENG was sufficient to illuminate 15 commercial blue LEDs. Thus, the developed PEF and PEF/rPET ENM-based tribolayers provide a promising pathway toward sustainable TENG fabrication and energy harvesting.