The fabrication of piezoelectric fibers using near-field electrospinning method for smart patch
| Autor: | Chih-Hao Tsao, 曹誌浩 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 This thesis is based on near-field electrospinning technique, from the interaction between solution weight percent, viscosity, electrical conductivity and contact angle of （Polyvinylidene fluoride, PVDF） and [Poly（γ-methyl l-glutamate）, PMLG]/PVDF composite solution. Use the best parameters to produce the piezoelectric fibers by rolling collection device. The piezoelectric fibers are placed on the interdigitated electrode structure, and a high electric field is applied to re-polarization the sample that could enhance the electromechanical conversion rates of piezoelectric fibers significantly. PVDF and PMLG / PVDF piezoelectric composite fiber is pasted on flexible PET substrate with interdigitated electrode structure, and the gap of structure is between 0.2 mm and 1mm. The experimental result shows that while the weight percentage of PVDF solution is 18 wt%, conductivity is 43.9 μs/cm, contact angle is 31.25°; and piezoelectric fiber with 0.95-4.1μm diameter can be produced by electrospinning. While the weight percentage of PMLG/PVDF solution is 30.69%, conductivity is 55.2 μs/cm and conductivity is 54.47°, the diameter of piezoelectric fiber is 7.11-17.3 μm. A 1.6×107 V/m electric field is set to re-polarization the piezoelectric fibers at 35°C and 65°C respectively, and a vibration with fixed frequency (8 Hz) is given to structure. According to the measurement results, PMLG / PVDF piezoelectric composite fiber could produce 0.191 V open circuit voltage and 720 nA closed current; which is 1.2-1.8 times higher than the energy harvester made by PVDF, and the conversion rate is increased by 77% comparing with the un-polarization traditional parallel electrode. Although the electrical performance of PMLG/PVDF piezoelectric composite fiber is higher than PVDF piezoelectric fiber, the fiber made by PMLG/PVDF will break easily because of the brittleness of material, that’s the main reason we choose PVDF fiber for further application. Electrical discharge machining process is used to fabricate the mold with 0.2 mm gap, and silver plastic is transfer printed on the flexible PDMS structure, that makes interdigitated electrode structure have conductivity. PVDF fiber is placed on the interdigitated electrode structure and packaged as a smart patch, the electric output of smart patch is higher then the one on PET patch. The PVDF fiber smart patch is arranged in array as a wide area detector for patient who is unable to move freely. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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