Electrochemical polymerization and characterization of a poly(azulene)-TiO2 nanoparticle composite film

A poly(azulene)-TiO2 composite film (PAz-TiO2) was synthesized electrochemically by oxidation of azulene in an electrolyte medium containing TiO2 nanoparticles. Polymerization was performed under magnetic stirring in an acetonitrile solution containing tetrabutylammonium hexafluorophosphate as the electrolyte salt. Influence of the concentration of TiO2 in the reaction suspension on the electrochemical and optical properties and on the structure of the composite films was studied by cyclic voltammetry, ex situ Raman and FTIR reflection spectroscopy and in situ UV-vis and FTIR spectroelectrochemical techniques. Morphology of the composite films was studied by Scanning Electron Microscopy and the amount and distribution of the TiO2 nanoparticles within the polymeric matrix by Inductively Coupled Plasma Mass Spectrometry with laser ablation. Addition of TiO2 in the reaction suspension had a small catalytic activity for the polymerization of Az. Inclusion of TiO2 nanoparticles in PAz did not affect the voltammetric behavior or the chemical structure of the formed polymer films. However, a different chain conformation and morphology of the film was formed when synthesized in presence of TiO2 compared to the plain PAz film. It was also found that the film morphology was more homogeneous when the concentration of TiO2 was a parts per thousand yen10 mM in the polymerization solution than films polymerized without any TiO2.