非對稱表面結構介電層在橫向摩擦生電下之研究

Study of Asymmetric Flexible Dielectric Layer on Lateral Sliding Electrification

謝文忻(Wen-Hsin Hsieh)

指導教授 ： 江宏仁

國立臺灣大學/工學院/應用力學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202103479

摘要

摩擦起電是環境中常見的一個現象，許多材料在不經意接觸或摩擦後便會產生靜電，在以往工業生產和生活上常常視其為負面影響，而2012年Wang, Z. L等人首次提出摩擦微奈米發電機(triboelectric nanogenerator, TENG)此應用[1]，開啟了摩擦起電另外一大發展性，可將環境與人體機械能轉換為電能並對小型電子用品供電，有機會取代傳統需要外部電源供電之設備，對環境永續發展與電子產品縮小化有很大的貢獻。為了提高摩擦電輸出，許多TENG研究在摩擦表面創造微奈米結構，提高材料接觸時的有效面積，然而，並無研究深入探討橫向摩擦下結構動態與輸出之間的關係，以及是否能利用結構設計達到訊號差異。
本論文利用光固化成型技術製作介電層翻模模具，並以鋁作為電極、PDMS作為柔性介電層基材，由於PDMS的柔軟特性，可使結構變形與產生不同響應。本研究首先為了提高摩擦輸出電壓，添加高介電常數奈米顆粒於PDMS形成複合材料介電層，提高介電質整體有效電容率，提高摩擦電壓，而為了改善顆粒佔據表面的負面影響，塗覆一層極薄PDMS於表面並有效改善此現象。我們也觀察到橫向摩擦過程中平坦介電層會產生黏滑現象，尤其在低速與高壓情況下，而黏滑運動產生的振動會影響電壓大小與平滑度。最後，我們設計非對稱鋸齒表面結構介電層，發現不同摩擦方向的電壓確實不同，而電壓與結構型貌及結構接觸及分離動態很相關，大的摩擦力道與快的分離速度使電壓增加，且摩擦力道為電壓變化主因。最後，為了可應用於實際生活，我們設計了偵測方向的特殊結構，結構由兩組不同數目之對稱鋸齒組成，藉由分離過程產生之峰值數目可成功判定摩擦方向．

關鍵字

摩擦起電裝置 ； 黏滑運動 ； 表面結構化介電層 ； 摩擦電荷密度 ； 方向感測器

並列摘要

Triboelectrification is a common phenomenon in the environment. Many materials generate static charge after inadvertently touched or rubbed, so it is usually regarded as a negative effect in fabrication processes and daily life. However, in 2012, Wang, Z. L et al. proposed a new type of technology called triboelectric nanogenerator(TENG), which can effectively convert mechanical energies generated from human movement or nature into electricity. This application provides power for small electronic devices and has potential to replace devices that require external power supply. The ability of self-powering makes a great contribution to environmental sustainability and the miniaturization of electronic products. In order to enhance the electric output performance of TENG, there have been many studies on the fabrication of micro/nano structures on surface to increase the effective contact area. However, few studies have discussed the effect of surface structure on output voltage based on lateral sliding electrification, also the possibility of signal difference based on structure designing.
In the thesis, we fabricated mold using stereolithography 3D printing and used PDMS as the flexible dielectric layer substrate, aluminum as the electrode. The surface structures can be deformed by the lateral movement of the upper electrode, inducing electric response as a result of the triboelectric effect. In the first part of the thesis, we modified the tribo-material by filling it with high permittivity nanoparticles to enhances the capacitance and output voltage of TENG. The effective friction area of PDMS reduces due to the filling particles occupy on the surface at higher filling content. By coating an extremely thin film of pure PDMS on the surface, we effectively improved the negative effect of particles on the surface. We have also observed that stick-slip phenomenon occurs while two surface of electrode and dielectric layer are sliding over each other, especially at the condition of low speed and high pressure. The vibration generated by stick-slip motion will affect the magnitude and smoothness of output voltage. Lastly, we propose an asymmetric flexible zigzag-patterned PDMS dielectric layer which is sandwiched between the aluminum electrodes with different angles on both sides that can generate different sliding electrification signals. We found that output voltage is closely related to the contact and separation dynamics of the structure, and both the deformation force and separation speed of are the cause of the voltage increase. Finally, we proposed a special structure for detecting direction, which is composed of two sets of symmetric zigzag with different numbers. The direction can be successfully determined only by the number of peaks generated by the separation process.

並列關鍵字

triboelectric nanogenerator ； stick-slip motion ； surface-structured dielectric layer ； triboelectric charge density ； orientation sensor

參考文獻

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