結合奈米感測材料之表面聲波式濕度感測器

近年來，對於發展一個量測濕度的系統有著龐大的需求，不僅可應用在產業需求上，也可監控環境之舒適度。截至當今，在諸多種類的濕度感測元件中，皆是以高分子濕度感測膜做為感測材料。因此，發展一種能在室溫下，穩定且容易合成的感測材料，以做為高精確、即時的濕度感測是迫切需要的。一個良好的濕度感測器，需具備以下之條件：高靈敏度、寬廣的動態範圍、快速響應、良好的重製性、簡易的介面電路、微型化、低成本。現存的感測器中，鮮少能在單一系統上滿足上述之需求。由於表面聲波式感測器所具備的許多良好特質，俾雀屏中選為此篇論文的感測裝置。本論文中，首先製作了一組頻率為145 MHz 以為基底的表面聲波共振器，並結合了自製的BJT放大器，構成雷利波震盪器。為了要形成一高靈敏之濕度感測器，鹽酸與樟腦磺酸為掺雜之聚苯胺奈米纖維俾滴附在共振器的感測區域以吸附待測氣體。此外，對於環境中干擾之雜訊諸如溫度及壓力效應，也使用了雙震盪器結構予以消除。最後，將製作之表面聲波式感測器，置於架設好之量測腔體中，並曝露於不同的相對溼度以探討感測器的響應，對於不同之兩種奈米纖維也做了量測與分析。實驗結果顯示，結合奈米感測材料與震盪器之表面聲波感測器，對於不同濕度下，皆能擁有良好的線性度與靈敏度。

關鍵字

表面聲波；濕度感測器；聚苯胺

並列摘要

There is a growing demand for developing a sensing system to measure relative humidity not only for human comfort but also for industry applications. Up to date, various sensitive materials with good sensing characteristics are mainly polymers. Thus, development of the real-time and precise humidity sensor which utilizes easy synthesis and stable sensing materials at room temperature is highly needed. A good sensor should be characterized by high sensitivity, wide dynamic range, fast response, good reproducibility, easy interface electronics, small size, and minimum cost. Existing sensors with single sensing system are hard for matching all these criterions. However, surface acoustic wave (SAW) sensing devices are promising candidates to pursue the above goals. In this thesis, a 145 MHz based SAW resonator was fabricated and integrated with the amplifier to form an oscillator. To function as a humidity sensor, HCL-doped and CSA-doped polyaniline nanofibers were coated on the delay line of the resonator as the sensing film. Moreover, dual channel configuration was constructed for reducing environmental influences such as temperature and pressure, etc. Then, the sensing devices were exposed to various relative humidity to investigate the performances and compared the efficiency between different materials on room temperature. Good linearity and high sensitivity were acquired toward various relative humidity sensing.

並列關鍵字

Surface acoustic wave ； Humidity sensor ； Polyaniline

參考文獻

[1] Kan-Sen Chou , Tzy-Kuang Lee, Feng-Jiin Liu, “Sensing mechanism of a porous ceramic as humidity sensor,” Sens. Actuators, B, Chem. 56, 106–111, 1999.

[2] Masanobu Matsuguchi, Toshiyuki Uno, Ayumi Yamanaka, Takaaki Kuroiwa, Tsutomu Ogura and Yoshiro Sakai, “Improvements in the long-term stability of a LiCl dew-point sensor using cross-linked porous poly(vinyl alcohol) film,” Sens. Actuators, B, Chem. 97, 74–80, 2004.

[3] Y. Li, M. J. Yang, N. Camaioni, G. Casalbore-Miceli, “Humidity sensors based on polymer solid electrolytes: investigation on the capacitive and resistive devices construction,” Sens. Actuators, B, Chem. 77, 625–631, 2001.

[4] F. Pascal-Delannoy, B. Sorli, A. Boyer, “Quartz Crystal Microbalance (QCM) used as humidity sensor,” Sens. Actuators, A, Phys. 84, 285–291, 2000.

[5] Sung Pil Lee, Kun-Joo Park, “Humidity sensitive field effect transistors,” Sens. Actuators, B, Chem. 35, 80–84, 1996.

國際替代計量

結合奈米感測材料之表面聲波式濕度感測器

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