以靜電紡絲研製高排列性聚(偏氟乙烯-三氟乙烯)薄膜及相關複合膜應用之研究

Abstract

本論文旨在以滾輪式收集器並控制靜電紡絲之各項參數，製造出具有高排列性的聚(偏氟乙烯-三氟乙烯) (polyvinylidene fluoride/trifluoroethylene, P(VDF-TrFE))(75/25)薄膜，此材料為鐵電性材料，具有良好的壓電性質、化學抗性、生物相容性及可撓性等等，故利用其作為可撓性壓電感測器的開發，並且為了提升其表現，藉由靜電紡絲製程，將絲線做成具有高度排列性，此特性可以令薄膜具有更多的β相，並且提升其作為感測器的靈敏度，並且為了進一步提升其作為感測器之效能，多加入了退火以及電暈極化的製程，令P(VDF-TrFE)之α相減少、β相更明顯，壓電特性更佳。文中將使用高壓交流電設備量測並繪製電滯曲線(Hysteresis loop)，以此判定其鐵電性質，再用掃描式電子顯微鏡與X-射線繞射儀器量測其表面結構、排列性以及薄膜所形成的晶相。雖然P(VDF-TrFE)經過靜電紡絲以及退火的過程提升了薄膜的韌性，但是在非軸向的結構十分脆弱，故以旋轉塗佈之方式將聚二甲基矽氧烷(Polydimethylsiloxane，PDMS)塗布至薄膜上，改善薄膜於非軸向之機械強度，並且提升其抗候性，提升其作為可撓式壓電感測器之潛力。

Using the electrospinning process to fabricate highly aligned arrays of nanofibers of poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)(75/25) were the main research topic in this thesis and we found the optimal parameters of electrospinning process to fabricate the highly aligned membrane. (P(VDF-TrFE) was a ferroelectric material and having several advantages, such as good chemical stability, high sensitivity, biocompatibility and strong piezoelectricity. Because of the above-mentioned advantages, (P(VDF-TrFE) membrane was suitable for the development of flexible sensors. After electrospinning process, (P(VDF-TrFE) nanofiber was aligned to become highly aligned membrane and it provided (P(VDF-TrFE) with more β phase, i.e., with higher piezoelectric performance. Furthermore, we used annealing and corona poling processes to enhance the piezoelectricity of (P(VDF-TrFE). In this thesis, we measured the hysteresis loop of (P(VDF-TrFE) membrane to determine its ferroelectricity. We also used X-ray diffraction (XRD) and scanning electron microscope(SEM) to observe its crystallization and surface structure. Although P(VDF-TrFE) was identified to have improved mechanical properties along the fiber axial orientation after electrospinning and annealing process, it was found to be weak along the lateral axis. To alleviate this problem, we coated polydimethylsiloxane (PDMS) on the membrane to enhance its mechanical properties, water resistant and promote potential on application of flexible sensor.