Waterproof, Breathable, and UV-Protective Nanofiber-Based Triboelectric Nanogenerator for Self-Powered Sensors

Nanofiber-based triboelectric nanogenerators (TENGs) have garnered increasing attention as the multifunctional power source in wearable electronics. However, most traditional wearable device-based TENGs are unable to simultaneously achieve excellent outputs and multifunctional properties. Here, we design a waterproof, breathable, UV-protective TENG based on a poly(vinylidene fluoride) (PVDF)/ poly(dimethylsiloxane) (PDMS)/TiO2 nanofiber film for effective harvesting mechanical energy by a simple and low-cost combined electrospinning/electrospray method. The introduction of PVDF can overcome the synthesis puzzle of PDMS nanofibers during the electrospinning process. With numerous three-dimensional micro-to-nano hierarchical pores of a nanofiber network, the constructed TENG can furnish large specific surface area and good breathability. The addition of TiO2 nanoparticles (NPs) increases the dielectric constant and surface roughness of the PVDF/PDMS/TiO2 nanofiber film as well as the corresponding output performance of the nanofiber-based TENG. The as-presented TENG has a maximum peak power density of 0.72 W/m2 and excellent breathability (18.6 mm/s). Due to the UV radiation absorbed by the TiO2 NPs, the UVA transmittance (TUVA) of the TENG with 4% TiO2 NPs is decreased to only 8.2%. The constructed TENG can be integrated to monitor human physiological signals in a self-powered manner. The nanofiber-based TENG provides a version to render these suitable for the daily-used wearable or portable electronics shortly.