具 pH 緩衝之導電功能性 PEDOT/ZnO 奈米複合薄膜之合成及性質研究

Abstract

本研究分為三部分，第一部份為以硝酸鋅和鹼進行水熱法反應製備奈米級的ZnO粒子，並使用不同的鹼和溶劑討論其對ZnO結晶和型態的影響。第二部份利用高溫快速成膜法聚合poly(3,4-Ethylenedioxythiophene)-PEDOT導電高分子薄膜，並討論不同pH值對PEDOT film摻雜程度的影響。第三部份為結合PEDOT和ZnO film，在PEDOT film上生成柱狀ZnO，並討論不同基材和反應條件對PEDOT/ZnO複合薄膜的型態及pH緩衝特性之影響。 在第一部分我們以水熱法合成ZnO奈米顆粒。以FT-IR和XRD鑑定其成分和晶型，並利用SEM觀察其型態。在這部分中我們發現不論是在水和乙醇中皆可製得ZnO，而在乙醇中所得的ZnO粒徑較小，pH緩衝的效果也較好。在第二部分我們以UV吸收峰的位置來判斷酸液和鹼液對PEDOT film摻雜程度的影響。在這部分中我們發現PEDOT film在酸性溶液中摻雜度會增加，而在鹼性溶液中摻雜度則會降低；pH=3-7之溶液會被PEDOT film調控至pH=3，pH=9之溶液則可以被調控至中性。在第三部分則結合PEDOT film和ZnO奈米顆粒。分別以PEDOT或ZnO對基材進行預處理，再以不同的條件長成一維六角柱狀ZnO，我們以SEM觀察其型態，最後再測試其pH緩衝性質。在這部分中我們發現以PEDOT/ZnO film對玻璃或PET不織布預處理之後，可成長出六角柱狀的ZnO，其aspect ratio大約為3；而由pH緩衝測試，我們發現，它對於pH=3-9之溶液皆可被調控到pH=7，因此可說明，這的確是一個對酸和鹼都有緩衝效果的PEDOT/ZnO複合薄膜。

This study is devided into three parts. First, by using hydrothermal growth, we use different alkalis to react with Zn(NO3)2 to synthesize ZnO nanoparticles in different solvents(water and ethanol) and discuss the effects on morphology and crystallinity. Second, we synthesize conducting polymer - PEDOT by oxidative polymerization and discuss the effect of solutions with different pH value on the doping level of PEDOT film. Third, we combine PEDOT and ZnO films to synthesize ZnO rods on each film, and discuss the effects of substrates and reaction conditions on the morphology and pH tuning ability of PEDOT/ZnO composite films. In the first part, we synthesize ZnO nanoparticles by hydrothermal growth method. The composition, crystallinity, and morphology of the ZnO nanoparticles are characterized by Fourier-Transformed Infrared Spectrophotometer(FT-IR), X-Ray Diffractometer(XRD), and Scanning Electron Microscope(SEM), respectively. ZnO particles can be obtained both in water and ethanol, and the paritcle size of ZnO synthesized in ethanol is smaller than that in water. And the pH tuning is better in ethanol than that in water. In the second part, the UV-Vis absorbance peak of PEDOT film is used to determine the doping level of PEDOT film. The doping level of PEDOT film increases when contacting with acid solutions, and decreases when contacting with alkali solutions. PEDOT film can tune solutions from pH=3-7 to pH=3, and pH=9 to pH=7. In the third part, we combine PEDOT and ZnO to synthesize a PEDOT/ZnO composite film. The substrate is first modified with ZnO film, PEDOT film, or both PEDOT and ZnO film. Then one dimensional hexagonal ZnO rods are grown on pre-modified substrates. Morphology of PEDOT/ZnO composite film is observed with SEM and the pH tuning effect is evaluated. After pre-modified by PEDOT/ZnO film on the glass or PET non-woven, ZnO rods of hexagonal structure can be obtained, with aspect ratio of 3. It can tune solutions of pH=3-9 to pH=7. Therefore, the PEDOT/ZnO composite film really works on pH tuning.