Nanostructured Polyaniline Based Composites-preparation, properties and applications

• Main Authors: Ying-Ying Horng, 洪瑛鍈
• Other Authors: Chia-Chun Chen
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/32465649963235046793

博士 === 國立臺灣師範大學 === 化學系 === 98 === Polyaniline is one of conducting polymers that has been widely studied for chemical, biosensor, supercapacitor and solar cell applications, owing to its unique reversible reduction/oxidation chemical behaviors enabling control over properties such as electrical conductivity and optical activity. In recent years, one-dimensional (1-D) polyaniline nanostructures, including nanowires, rods, and tubes have been studied with the expectation that such materials will possess the advantages of both low-dimensional systems and organic conductors. However its application is needed to be further investigated and clarified in reality. Therefore, the preparation, properties and applications of nanostructured polyaniline based composites including glucose sensor and supercapacitor were described in the present work. In the first part of this study, we provide a convenient route to directly grow polyaniline nanowires (PANI-NWs) onto the surface of carbon cloth (CC) by an electrochemical method followed by incorporation of glucose oxidase (GOx) to fabricate the amperometric enzyme electrodes. CC was specifically selected as the current collector due to its cost-effectiveness, high conductivity, reasonable chemical stability, and 3D structure with high porosity, hence high surface area support for PANI-NWs growth. The defect-free interfaces, along with the excellently sensitive organic nanostructured-surface, as evident from its significantly large effective surface area (24 times the geometric area) for redox-sensing, allows efficient entrapment/immobilization and sensing of biomolecules, via rapid electron-transfer at NWs-CC. The GOx-immobilized PANI-NWs/CC exhibited an excellent sensitivity, ~2.5 mAmM-1cm-2 to glucose, over detection range 0-8 mM, adequate for clinical monitoring of human glucose levels. This work clearly reveals a cost-effective simple system possessing enormous potentiality for biosensors, bioenergy and bioelectronics applications. In the supercapacitor applications, relatively high gravimetric capacitance of 1079Fg-1 at a specific energy of 100.9 Whkg-1, a specific power of 12.1 kWkg-1 and exceptionally high area-normalized capacitance of 1.8 Fcm-2 were achieved for the PANI-NWs/CC electrodes. The diffusion length of proton within the PANI-NWs was estimated to be about 180nm by electrochemical impedance analysis, which indicating the electrochemical performance of the electrode is not limited by the thickness of PANI-NWs. On the other hand, the electrodes of PANI/CNx NTs-CC composite by growing directly nitrogen- containing carbon nanotube (CNx NTs) onto a CC followed by coating PANI by in-situ polymerization process were performed in order to enhance the power density of PANI-based supercapacitor. Results showed the power density of PANI/CNx NT-CC is threefold higher than PANI-NWs /CC due to minimization of internal and contact resistance between CNx NTs and CC. Therefore, the use of PANI-NWs/CC and PANI/CNx NTs-CC nanocomposite electrodes as supercapacitor revealed credible attention in the commercial availability.