Thermal Drawing of Graphene-Polyvinylidene Fluoride Fibers for Self-Powered Sensing

Triboelectric nanogenerators (TENG) harvest low-frequency mechanical and biomechanical energy by the combined effect of triboelectrification for generating surface charge and electrostatic induction for guiding electrons through an external circuit. Ferroelectric polyvinylidene fluoride (PVDF) has excellent triboelectric properties due to its highly electronegative fluorine ions, high dielectric constant non-toxicity, flexibility, low processing temperature, and resistance to environmental effects. The high dielectric constant of PVDF results in spontaneous polarization, increasing triboelectric charge density in the friction layer. Incorporating 2D materials into PVDF promotes the electroactive phase transition of the polymer. Graphene and its derivatives have been extensively used as 2D materials with wearable TENG devices owing to their exceptional electrical properties. This work examines the performance of thermally drawn PVDF fiber at varying graphene nanoplatelet (GNP) concentrations (1%, 3%, and 5wt%). The 5% GNP-PVDF fiber showed maximum improved electrical performance with increased open circuit voltage and short circuit current 1.41 and 1.48 times, respectively, compared to the pristine PVDF TENG fiber. The fabric GNP-PVDF TENG demonstrated a maximum power output of 32.14 µW at a matching load of 7 MΩ while the power density was 53.57 mW m⁻². The TENG fabric was employed for biomotion monitoring and analysis. The devised TENG remained stable in harsh conditions such as high/low temperature, alkaline medium, multi-washing cycle, and extended usage cycle.