請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/49460
標題: | 壓電駐極體表面電荷水洗恢復機制之研發 Research and Development of Piezoelectret Surface Charge Water-washed Recoverable Mechanism |
作者: | Ya-Ling Chang 張亞琳 |
指導教授: | 李世光(Chih-Kung Lee) |
關鍵字: | 壓電駐極體薄膜,三明治結構,可水洗濾網,電荷恢復機制,PM2.5, piezo-electret membrane,sandwich structure,washable filter,charge-recovery mechanism,PM2.5, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 本論文主要聚焦於電荷水洗恢復機制的研究以及具有電荷水洗恢復特性的壓電駐極體薄膜的開發。電荷恢復能夠提升駐極體空氣濾網的過濾效果以及使其使用成本降低,因此在此應用上,電荷恢復效應是期望能夠被實現的。在實際使用層面,為了使駐極體濾網保持相當的過濾效果,在一定的使用時間過後,駐極體濾網需要被清洗或是更換。然而,更換濾網使得空氣過濾的成本提高,而水洗卻會使駐極體濾網因流失大量靜電荷而降低過濾效果。對於此問題,有兩個解決方案。第一,藉由結構設計使駐極體濾網本身具有水洗後能夠恢復表面電荷的特性;另一個策略為再次對駐極體濾網充電以補充流失的電荷,二次充電被設計為在常溫下進行,此條件較符合實際應用的情境。在本論文中,將會討論此兩個步驟,以了解壓電駐極體水洗後自發性恢復電荷的能力以及二次充電的效率。
主要的兩個實驗所使用的試片分別為層狀壓電駐極體及駐極體薄膜,在此結構中包含聚四氟乙烯、環烯烴共聚物以及偏氟乙烯-三氟乙烯等材料。複合駐極體材料及壓電材料的聯合應用使得高電荷儲存量及穩定的內電場能夠同時存在。高電荷儲存量是藉由聚四氟乙烯的孔洞結構來實現,此駐極體薄膜的外層被環烯烴共聚物所包覆,此附加的聚合物薄膜具有防水的效果,因此能防止電荷流失。另一方面,穩定的內電場由多層結構中的其中間層偏氟乙烯-三氟乙烯所提供,此壓電層中排列有序的偶極矩為內電場的來源。此外,為了進一步改善壓電駐極體薄膜的電荷恢復能力,電荷流失及電荷水洗後恢復的機制也在此論文中討論。總結來說,一種三明治結構表面電荷可水洗恢復的壓電駐極體被成功地開發,此壓電駐極體可望對駐極體濾網的應用層面做出改善,除了能夠使其可水洗而增長其使用壽命外,使用駐極體濾網的成本也可望被降低。 This thesis focuses on the research of the charge-recovery mechanism after water-wash and the development of a piezo-electret membrane which exhibits the voltage-recovery feature. The charge-recovery effect is desired for the electret air-filter application which may improve the filtration efficiency and also make air-filtration more economical. In order to maintain air-filtration efficiency at a satisfactory level, it is required to clean or substitute a new filter after a period of functioning time. However, replacing a new filter each time makes air-filtration costly and cleaning by water-wash can seriously damage the effectiveness of the electret filter due to the substantial loss of static charges. Two solutions were raised with an attempt to solve this problem. One is making the electret membrane charge-recoverable after being washed by the approach of structure design. Another strategy is to charge the electret membrane again to replenish the lost charges however in room temperature environment which is similar to the real scenario of application. These two procedures were both discussed in this thesis in order to know the ability of spontaneously charge-recovery and the efficiency of secondary charging. For these experiments, the piezo-electret and electret samples are designed in multi-layer structures in which expanded polytetrafluoroethylene (ePTFE), cyclic olefin copolymer (COC) and poly(vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)] are employed. The synthetic application of composite electret materials and piezoelectric materials make it possible to possess both advantages of high charge storage capacity and stable internal field. The high charge storage capacity is due to the porous structure of ePTFE. This electret membrane is also improved by COC-coating layers which can function as water-proof layer to retain the charges. Moreover, the concentration of COC solution has also been optimized for the best charge storage and charge recovery performance. On the other hand, the stable internal field is provided by the P(VDF-TrFE) thin film inserted in the multi-layer structure owing to its well-oriented dipoles. In addition, in order to further improve the charge-recover ability of the piezo-electret samples, the mechanism of charge decay after charging, charge recovery after washing are also investigated in this thesis. In conclusion, a charge-recoverable piezo-electret sandwich device has been successfully developed and the corresponding mechanisms are also investigated preliminarily. This device is potentially useful for the electret air-filter application which makes the filter washable so that the lifetime of filters is prolonged with fairly high filtration efficiency. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/49460 |
DOI: | 10.6342/NTU201602717 |
全文授權: | 有償授權 |
顯示於系所單位: | 應用力學研究所 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-105-1.pdf 目前未授權公開取用 | 4.05 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。