使用奈米碳粉與PDMS的導電彈性複合材料配合軟微影黃光製程技術製作高敏感度彈性應變感測器

Abstract

本研究目標為使用軟微影技術(Soft Lithography)製作出高敏感度彈性應變感測器。彈性應變感測器比起傳統硬質感測器還要適合應用在人體皮膚的感測，而過去通常以光蝕刻技術(Photolithography)等方法製作彈性應變感測器，但光蝕刻技術的缺點為製程較多不適用於大量製造。因此本研究使用製程較少適合大量製造的軟微影技術將彈性導電體製作成彈性應變感測器，並且藉由改變混合比例、感測器結構、厚度等特性提升感測敏感度與穩定性。 本實驗使用導電材料奈米碳粉與彈性材料聚二甲基矽氧烷(PDMS)混合製作出彈性導電體，以軟微影技術中的微壓印技術(Micro-patterning)製作不同格數圖案的微結構，並且透過重複壓印步驟製作出不同厚度的微結構，以及使用光學顯微鏡觀看導電彈性體微結構以及量測微結構的厚度，並且量測應變規的壓阻性且得出應變係數。實驗結果顯示，製作出的彈性導電體的壓力對電阻變化的電特性接近於線性。而在不同格數圖案應變規應變係數量測結果顯示，格數越多的圖案應變係數越高。而在不同厚度應變規的製作結果得出，隨著壓印次數增加，CPDMS厚度會增加。此外，不同厚度應變規的量測結果得出，CPDMS厚度較薄的應變規的應變係數比CPDMS較厚的應變規的應變係數高。目前得到較佳的參數為5格圖案，厚度120μm的應變規，量測出最高的應變係數約為5.07。

In this study, a high sensitivity, flexible strain sensor is fabricated by using soft lithography. Flexible sensors are more suitable applied on human body sensing than conventional sensors. Flexible strain sensors are usually fabricated by photolithography. However, the disadvantage of photolithography is that it will take too many processes, so it is unsuitable in mass production. Hence, we will fabricate flexible strain sensor by using soft lithography that uses less processes than photolithography, so that it will be suitable in mass production. Moreover, the piezoresistive coefficient and sensitivity of flexible strain sensor will be increased by changing size parameters such as length, width and thickness. In this study, flexible material PDMS and conductive material carbon black are used to fabricate conductive elastomer CPDMS. The different shape of CPDMS micro structure is fabricated by using micro-patterning, and the different thickness of CPDMS micro structures is fabricated by increased repetitive printing number. The piezoresistance of the strain gauges is measured, and then the gauge factor of the strain gauge is evaluated. Experiment results show that the piezoresistive coefficient of CPDMS with the optimal proportions is approximately linear. Fabrication results show that when the repetitive printing number is increased, the thickness of CPDMS will be increased. Gauge factor measure result show that the number of grids of the strain gauges will affect gauge factor, the gauge factor of Grid5 strain gauge is the highest. In addition, the thickness of strain gauge will affect gauge factor, the gauge factor of thin strain gauge is the highest. The highest gauge factor is 5.07.