PVDF/Polydopamine-Modified BaTiO₃ Nanofiber-Based Triboelectric Nanogenerators with Drum Collector Speed Optimization

The incorporation of inorganic nanofillers into poly(vinylidene fluoride) (PVDF) and electrospinning based on a rotating drum collector are the commonly used strategies for enhancing the crystallinity of PVDF. However, interfacial defects between the nanofillers and PVDF matrix cause deformation and fracture of the nanofibers (NFs) during the rotation of the drum collector, hindering the effective transmission of tension to the NFs. In this study, surface modification of BaTiO₃ (BTO) nanoparticles (NPs) with polydopamine (PDA) was performed to enhance their interfacial compatibility with PVDF, ensuring effective stretching of the NFs even at high rotational speeds of the drum collector. When PDA-coated BTO (BTO@PDA) NPs were used as nanofillers in the PVDF matrix, the interfacial defects and NP agglomerations were reduced, and the interfacial interaction with PVDF was reinforced. This improvement enhanced the mechanical properties of the PVDF/BTO@PDA NFs, such as Young’s modulus and elongation at break. When PVDF/BTO@PDA NFs were used as the negative triboelectric material, the output performance of the triboelectric nanogenerator (TENG) was enhanced. Specifically, when BTO@PDA NPs were used as nanofillers, the output voltage and current continued to increase, even at higher drum collector rotational speeds than when BTO NPs were used. The mechanism behind the enhancement of TENG performance using the surface functionalization of BTO NPs with PDA was investigated by measuring the crystallinity and surface potential of the PVDF/BTO@PDA composites.