Fabrication of β-phase poly (vinylidene fluoride) piezoelectric film by electrospinning for nanogenerator preparations

Electrospun poly (vinylidene fluoride) (PVdF) has been recognized as a potential candidate for making nano-generators in a broad range of applications. Through electrospinning, PVdF fiber films can be fabricated while enhancing the β-phase content within it. The electrospinning process was carried out with optimal parameters to obtain uniform and well-aligned fibers. The morphology of the PVdF fiber film, observed by Scanning Electron Microscopy (SEM), showed uniform, smooth and consistent fiber formation without beads, and the fiber diameters were in the range of 700 - 1000 nm. The crystalline phase of the PVdF was characterized by analyzing the X-ray Diffraction (XRD) pattern and Fourier-Transform Infrared (FTIR) spectrum. The β-phase content of the electrospun film was 80.1%, while that of the solvent cast PVdF film was 64.4%. This result shows that electrospinning has increased the percentage of the β-phase in the film. The force applied and the output voltage of the constructed nano-generator detected are linearly correlated within the measurement window. The maximum voltage generated was about 1.0 V with finger tapping and 1.3 V with a custom-designed tapping machine. Improvements to this PVdF piezoelectric nano-generator can be used in many potential applications in several fields, especially as energy harvesters, biomedical applications and sensors.