Study of BST/PVDF Piezoelectric Fiber Composites by Near-Field Electrospinning for Energy Harvester

• Main Authors: Yi-Ting Wang, 王怡婷
• Other Authors: Cheng-Tang Pan
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/h8979t

碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 107 === In this study, we apply near-field electrospinning (NFES) to prepare BaxSr1-xTiO3 (BST)/ Poly (vinylidene fluoride) (PVDF) piezoelectric fiber composite with excellent mechanical properties and chemical properties. BST ceramic powder are blended with PVDF solution uniformly to prepare a solution of appropriate conductance. The BST ceramic powders are prepared by a Sol–gel method. Parameter of BST/PVDF fiber process are based on PVDF fiber where electric field is 1.40×107 V/m, tangent speed of collecting device is 2618.10 mm/s, and speed rate of infusion pump is 0.50 ml/hr. When the droplet overcame the surface tension of BST/PVDF solution to form Taylor cone at high electric field, a BST/PVDF piezoelectric fiber was spun from the tip of Taylor cone and collected by a rotating glass collector. Scanning electron microscope (SEM), Differential scanning calorimetry (DSC), micro tensile testing and Fourier transform infrared (FTIR) and electricity test of the blends of BST/PVDF fibers are carried out The mechanical properties of fibers are measured by Micro-tensile testing. The effects of different ratio of Ba/Sr and different content of Ba0.7Sr0.3TiO3 ceramic powder on BST/PVDF piezoelectric fiber are discussed. Finally, BST/PVDF piezoelectric fiber composites are patterned on a PET-based structure with Interdigital electrode (IDT) as a BST/PVDF flexible energy harvester to capture ambient energy. The results show that the BST ceramic powder were ~58.14-92.75 nm and the diameters of piezoelectric fiber composites were ~6.75-13.75 µm. The elastic modulus of piezoelectric fiber composites is ~72.90 GPa and the strength ranged from ~3.74 MPa. The mechanical properties are 2-3 times higher than PVDF piezoelectric fiber. The maximum open circuit voltage and close loop current of BST/PVDF fiber are reached to ~1025 mV and ~391 nA, respectively. The output power of BST/PVDF fiber under 13.60 MΩ is ~24463.11 pW. The electro-mechanical energy conversion efficiency of the BST/PVDF energy harvester is 1~2 times higher than PVDF energy harvester. It is confirmed that the addition of BST ceramic powder can effectively increase the piezoelectric constant of PVDF piezoelectric fiber. BST/PVDF piezoelectric fiber composites with good piezoelectricity could apply to wearable sensors and energy harvesters.