Synthesis of Novel Functional Conductive Polymers in Supercritical Carbon Dioxide and their Properties

点击翻译按钮获取中文摘要

In this work, we have investigated the electrochemical synthesis of conductive polymers in homogenous supercritical condition. The effects of several factors such as pressure, phase behavior and mass transfer process for the obtained polymer film were examined.Thiophene was chosen as a model monomer to electropolymerize in supercritical carbon dioxide (scCO_2). The homogeneous supercritical state was confirmed by the observation of the phase behavior through a high-pressure cell with a viewing window. The conductive polymer film of thiophene synthesized in scCO_2 was characterized with cyclic voltammetry, SEM, Laser microscopy, AFM and four-point probe conductivity. The roughness of the film in that system was decreased with the further addition of CO_2. This result suggested that the low viscosity of scCO_2 play an important role in improving the transfer rate of solvent. The roughness of the film prepared in the homogeneous scCO_2/ acetonitrile (AN) system was reduced compared with t … More hat prepared in dichloromethane. The slow growth of the film and the high diffusion rate of the monomer seemed to account for the smooth and flat film formation. Other conductive polymers, polyaniline and polypyrrole, were successfully synthesized in a homogeneous scCO_2/ AN system.This electropolymerization system was extended to the polymerization of thienylporphyrin (H23ThTEtP) for the application as a superoxide sensor. The resulting film of H23ThTEtP was characterized using SEM, laser microscopy and AFM. It was revealed that the electropolymerized film in scCO_2 provided flatter, smoother and higher densified active sites than the one electropolymerized in organic solvent.The polymerized film as an electrocatalyst was applied to a superoxide sensor. The catalyst displayed selectivity and activity for the oxidation of 02・and showed a linear relationship between current and 02・concentration, which revealed the possibility of quantitative analysis of 02・in vivo. The catalyst showed higher sensitivity than the one electropolymerized in organic solvent. Less