Electrosynthesis and characterization of poly(2-[(E)-2-azulen-1-ylvinyl] thiophene) using polyazulene as model compound

Electrochemical polymerization of azulene and 2-[(E)-2-azulen-1-ylvinyl] thiophene has been studied in this work. Characterization of the formed films was done by cyclic voltammetry (CV), in situ UV–vis absorption spectroscopy and by scanning electron microscopy (SEM). Polymerization was performed by CV in a three-electrode electrochemical cell in 0.1 M tetrabutylammonium hexafluorophosphate-acetonitrile (TBAPF6-ACN) within two different potential ranges. The redox behavior of the films was studied by CV in monomer-free TBAPF6-ACN electrolyte solution. The electrochemical response from the anodic charging (p-doping) in the different films consisted of symmetric and well-resolved redox peaks. During electrochemical doping changes in the UV–vis spectra can be seen due to transformation of the films from the neutral into the doped form. Poly(2-[(E)-2-azulen-1-ylvinyl] thiophene), in particular shows a very broad absorbance spectrum starting at 300 nm extending to 900 nm. Morphologies of the electrosynthesized films were studied by SEM.