Electrochemical deposition of polyviologen-reduced graphene oxide nanocomposite thin films

In previous years, a series of polyviologen films (PVs) have been synthesized through electrochemical polymerization in our group. In order to improve their electrochemical properties, a thin composite film of these redox polymers and reduced graphene oxide were prepared using a one-step technique. In this work, the cyanopyridine based monomer and the graphene oxide flakes were initially dissolved in an ionic liquid (IL), after which the electrochemical reduction was performed. A branched polyviologen film was formed during the electrochemical process, while the graphene oxide flakes were reduced and immobilized in the polyviologens network. The resulting composite film was characterized by electrochemical, spectroscopic, and imaging techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, UV-vis, FT-IR, Raman spectroscopy, and SEM. The analysis indicated a successful composite film formation: the redox property was enhanced by the presence of graphene in the polyviologen films. Such an easy fabrication process together with inexpensive precursor materials demonstrates a facile way for producing thin composite films for different electrochemical applications, such as electrochromic devices and sensors.