高分子-奈米粒子混摻材料製作之感測器

以共軛高分子為基底之混摻材料具備製程簡單、低價格以及可在室溫下操作等優點，所以我們嘗試將其應用在氣體感測之領域，希望可以達到高感應度、準確、快速反應、感測範圍廣與低成本等特性。於本論文第一部分之研究，主要是探討將二氧化鈦奈米桿(TiO2 nanorods)加入聚三己基噻吩中(poly(3-hexylthiophene), P3HT)，並且調控此混摻材料之電性與表面形態以改善混摻材料的氧氣感測靈敏度。我們的結果呈現當聚三己基噻吩混摻二氧化鈦奈米桿時，其氧氣感應度相較於純的聚三己基噻吩為佳，所以我們針對聚三己基噻吩與二氧化鈦奈米桿混摻比例做最佳化，因為不同的混摻比例有可能改變表面形態、相分離行為以及表面電位等特性，最後我們發現最佳的混摻比例為：WP3HT/WTiO2 nanorods = 1/1時會有最高感應度，相較於純的聚三己基噻吩，得到的感應度約可增加2倍(感應度由1.2變為2.4)。此結果顯示聚三己基噻吩混摻二氧化鈦奈米桿於室溫氧氣感測具備相當大的潛力。另一方面，在本研究的第二部分主要是針對揮發性有機化合物(volatile organic compounds, VOCs)感測器之探討。揮發性有機化合物大多具有毒性、易揮發及造成環境污染等特質，且在現今社會中大量用於工業製程中，使用量十分驚人。所以能夠準確並即時地監控這些揮發性有機物的儲存、運送與反應過程是一個很重要的課題，這將可以避免人員、財物以及環境受於揮發性有機物外洩的威脅。而在此我們利用聚三己基噻吩與碳六十衍生物[6,6]-phenyl-C61-butyric acid methyl ester(PC61BM)混和製作揮發性有機物感測器，它具備準確、快速反應、感測範圍廣與極低成本等特性，同時感測晶片安裝極為容易，可應用於管線接口、儲存槽或工廠等有潛在外洩危險之區域；另一個優點是由於它的反應時間快，可以在短時間內即時偵測到異常外洩，然後發出警告。本論文中主要研究此感測器之基礎特性以及將製程參數最佳化，製程參數的部分針對聚三己基噻吩分子量、旋鍍轉速以及混摻比例等參數進行調校，而從結果發現在分子量60 kD、轉速5000 r.p.m.以及混摻比例為：WP3HT/WPCBM = 1/1時之感應效果最好；之後我們利用最佳參數分別針對各種有機物做感應度、感應曲線與感應極限等測試，在感應度與感應曲線的部分，每種揮發性有機物都有它不同的感應特性，我們可從感應曲線得到擬合公式，往後實際上在感測應用時可以藉由我們建立起來的資料庫內尋找相似的化合物；而另一方面，感測器不會對水以及醇類產生反應，代表感測器在使用時訊號不會被水氣干擾，不須經過額外除水步驟。感應極限的部分，有8種揮發性有機物(n-Hexane、n-Octane、Toluene、o-Xylene、Chlorobenzene、Dichlorobenzene、Tetrachloroethylene以及Acetone)可以藉由我們的感測器在10分鐘內檢測到比美國勞工部之職業安全衛生署訂立的揮發物允許曝露濃度還低的濃度。在實體揮發物感測器製作部分，我們將此揮發性有機物感測器的構想於以實現，其可安裝於存放揮發性有機物的儲存槽和管線接縫處，可即時偵測是否有有機物洩漏，也有實際上進行測試，功能相當正常，且成本極為低廉。

關鍵字

感應器；揮發性有機物；高分子

並列摘要

Conjugated polymers based materials are investigated as materials for gas sensing due to they offer the advantages of easy processing, low cost and room temperature operation. The incorporation of inorganic nanoparticles into conjugated polymers also enables tuning the properties of conjugated polymer based materials to improve the sensitivity as it is served as active material for oxygen sensor. We demonstrate by using the hybrid materials based on poly(3-hexyl thiophene)(P3HT) in combination with TiO2 nanorods, significant improvement in oxygen sensing properties is obtained as compared to pristine P3HT. Composition studies reveal that the oxygen sensor sensitivity is significantly increased with the increase of TiO2. The obtained improvement in oxygen sensing sensitivity is attributed to the change of surface properties, electronic properties and morphology of the hybrid materials with TiO2. The results suggest the hybrid P3HT:TiO2 nanorods is promising for resistive oxygen sensing at room temperature. On the other hand, the present research demonstrates a proposed methodology for sensing volatile organic compounds (VOCs). Numerous VOCs which are typically toxic, volatile and environmental hazard are nowadays widely used in industrial production. To real-time and accurately monitoring the storage or transporting of VOCs is extremely important which protects human, property and environment from damage of VOCs leakage. The present work utilizes the poly(3-hexylthiophene) (P3HT)/ [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend to sensing various VOCs. The sensor is found to feature high sensitivity, high accuracy, quick response, broad sensing range, and very low cost. The developed sensor is ease of fabricating into a sensing chip and can be placed anywhere such as pipe joints and tank switches that are potential in VOCs leakage. Real-time sensing is achievable based on the instant response and thus alarm can be activated within few minutes for in time remedies. The research starts from investigation of fundamental knowledge, processing tuning, performance testing and finally extends to sensor device fabrication that can practically perform the sensing capability. The demonstrated results significantly advance the current sensor technology and are promising in commercial validity in near future for human and environmental safety concerns.

並列關鍵字

sensor ； polymer ； hybrid ； VOCs

參考文獻

[1] H. F. Lu, F. Li, G. Liu, Z. G. Chen, D. W. Wang, H. T. Fang, G. Q. Lu, Z. H. Jiang, H. M. Cheng, “Amorphous TiO2 Nanotube Arrays for Low-Temperature Oxygen Sensors,” 2008, Nanotechnology, 19, 405504.

[2] W. Gopel, G. Rocker, “Intrinsic Defects of TiO2(110): Interaction with Chemisorbed O2, H2, CO, and CO2,” 1983, Physical Review B, 28, 3427.

[3] W. J. Fleming, “Physical Principles Governing Nonideal Behavior of the Zirconia Oxygen Sensor,” 1977, J. Electrochem. Soc., 124, 21.

[4] L. Gao, Q. Li, Z. Song, J. Wang, “Preparation of Nano-Scale Titania Thick Film and its Oxygen Sensitivity,” 2000, Sensors and Actuators B, 71, 179.

[5] M. S. A. Abdou, F. P. Orfino, Z. W. Xie, M. J. Deen, S. Holdcroft, “Reversible Charge Transfer Complexes Between Molecular Oxygen and Poly(3-alkylthiophene)s,” 1994, Adv. Mater., 6, 838.

國際替代計量

高分子-奈米粒子混摻材料製作之感測器

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