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Synthesis and characterization of conducting copolymers of thiophene ended poly(ethyleneoxide) : their electrochromic properties and use in enzyme immobilization

Yıldız, Hüseyin Bekir
Thiophene ended poly(ethylene oxide) (ThPEO) and random copolymer (RPEO) of 3-methylthienyl methacrylate and p-vinylbenzyloxy poly (ethyleneoxide) units were synthesized chemically. Further graft copolymerization of RPEO and ThPEO with pyrrole (Py) and thiophene (Th) were achieved in H2O - sodium dodecylsulfate (SDS), H2O - p-toluenesulphonic acid (PTSA) and acetonitrile (AN) - tetrabutylammonium tetrafluoroborate (TBAFB) solvent electrolyte couples via constant potential electrolyses. Characterizations were performed by cyclic voltammetry (CV), nuclear magnetic resonance spectroscopy (NMR), and fourier transform infrared spectroscopy (FTIR). The morphologies of the films were examined by scanning electron microscopy (SEM). Conductivities of the samples were measured by using four-probe technique. Moreover, spectroelectrochemical and electrochromic properties of the copolymers obtained from thiophene were investigated by UV-Vis spectrometry and colorimetry. . Immobilizations of alcohol oxidase and polyphenol oxidase enzymes were performed in the matrices obtained via copolymerization of ThPEO and RPEO with pyrrole. Immobilization was carried out via entrapment of enzyme in matrices during the polymerization of pyrrole. Temperature optimization, operational stability and shelf-life of the enzyme electrodes were investigated. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined. It is known that wine includes phenolic groups that give astringency in high concentrations. Polyphenol oxidase (PPO) converts mono and diphenols to quinone. By analyzing the product, one can find out the amount of phenolic groups. By using the enzyme electrodes via immobilization of PPO, amount of phenolics in different wines were analyzed.