Enzymatic polymerization of hydroxy-functionalized carbazole monomer

Up to date, enzymatic polymerization of phenolic compounds bearing different moieties such as ferrocene, sugar, furamide, and male-imide have been reported. In this study, horseradish peroxidase (HRP)-catalyzed polymerization of another hydroxy substituted aromatic compound, 2-hydroxycarbazole (HC), was firstly presented. The structure of the polymer (PHC) was verified by using nuclear magnetic resonance and infrared techniques. Further characterization was carried out by means of TG, DSC, CV (cyclic voltammetry), SEM (scanning electron microscopy), fluorescence analyses, and solid state conductivity measurements. Average molecular weight of the polymer was determined by gel permeation chromatography and was around two thousands. The optical and electrochemical band gaps of PHC were dramatically lower than those of HC. The photochemical behaviors of HC and PHC were investigated by recording the fluorescence spectra in two different solvents. Solid state conductivity measurement showed that the electrical conductivity value of hydroxyl-functionalized carbazole polymer is relatively higher than those of the previously reported phenol polymers in the literature. Moreover, the conductivity of PHC increased by doping with iodine vapour.