Polyvinylidene Fluoride-Added Ceramic Powder Composite Near-Field Electrospinned Piezoelectric Fiber-Based Low-Frequency Dynamic Sensors

In
this study, near-field electrospinning (NFES) is used to fabricate
BaxSr1–xTiO3 (BST)/poly­(vinylidene fluoride) (PVDF) piezoelectric
fiber composites with excellent mechanical properties and chemical
properties. BST ceramic powder is blended with PVDF solution uniformly
to prepare a solution of appropriate conductance. The parameter for
BST/PVDF fiber processing is based on PVDF fibers. Scanning electron
microscopy, differential scanning calorimetry, microtensile testing,
Fourier transform infrared spectroscopy, and electricity test of the
blends of BST/PVDF fibers are incorporated. Mechanical properties
of the fibers are then measured by microtensile testing. Effects of
distinct ratios of Ba/Sr and the content of Ba0.7Sr0.3TiO3 ceramic powder on BST/PVDF piezoelectric
fibers are discussed. Finally, BST/PVDF piezoelectric fiber composites
are patterned on a poly­(ethylene terephthalate) (PET)-based structure
with an interdigital electrode as a BST/PVDF flexible energy harvester
to capture ambient energy. The results show that the BST ceramic powder
is ∼58–93 nm, and the diameters of piezoelectric fiber
composites are ∼6.8–13.7 μm. The tensile strength
of piezoelectric fiber composites is ∼74.92 MPa, and the Young’s
coefficient tensile strength is ∼3.74 GPa. Mechanical properties
are 2–3 times higher than those of pure PVDF piezoelectric
fibers. The maximum open-circuit voltage and closed-loop current of
BST/PVDF fibers reached ∼1025 mV and ∼391 nA, respectively.
The electromechanical energy conversion efficiency of the BST/PVDF
energy harvester is found to be 1–2 times higher than that
of the PVDF energy harvester. It is confirmed and validated that the
addition of BST ceramic powder could effectively increase the piezoelectric
constant of PVDF piezoelectric fibers.