| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 99 === In this study, the electrocatalytic activity of carbon nanotubes (CNT) in temperature sensitive poly(N-isopropylacrylamide)(PNIPAAm) (LCST about 32 ℃) composites that were cast on glassy carbon electrode (GCE) as a working electrode was investigated by cyclic voltammetry (CV) using potassium ferricyanide (K3Fe(CN)6) as a probe. The CNT/PNIPAAm composite-modified GCE was subsequently investigated on its sensing capability for dopamine, uric acid, and vitamin C. The study variables include the temperature at which GCE was modified, the content of CNT in the composite, the acid treatment conditions of CNT, the working temperature of GCE. FE-SEM images found that CNT and acid-treated CNT (f-CNT) dispersed in PNIPAAm solutions of different temperature showed different uniformity of CNT in the cast films. At a given temperature at which the composite was cast, f-CNT exhibited much better uniformity than CNT. CV and FE-SEM data found that CNT with a better dispersion in composite exhibited a higher electrocatalytic activity.The f-CNT in the 25℃(below LCST)-cast composite films and used to probe the redox reactions of (K3Fe(CN)6) at 37℃ (above the LCST) showed much improved electrocatalytic activity. The electrocatalytic activity of CNT was found to increase with increasing amount of CNT. The 25℃-cast f-CNT/PNIPAAm 2/10 composite on GCE could simultaneously detect dopamine, uric acid, and vitamin C at 37 ℃, with oxidation potentials at 0.207V, 0.34V, and -0.02V, respectively, in 0.1 M KCl aqueous solution with 0.1 M PBS (pH 7.4).
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