In-situ Composite Films and Electrochromism of Polyaniline and Poly(vinyl alcohol)

The composite films of polyaniline and poly (vinyl alcohol) (PVA-PAN) were electrochemically synthesized in-situ via potentiostatic technique. The effects of aniline concentration and acid species on the electrical and optical properties of the composite films were studied by using cyclic voltammetric and in situ UV-vis spectroelectrochemical methods. It was found that the composite films stick more tightly on the ITO electrode and show more uniform appearance, stronger electroactivity and faster response than pure polyaniline film without PVA substrate. The PVA-PAN composite films show transparent colorless state at the potential range of -0.50 V to -0.14 V, and purple state at the potential range of + 0.40 V to + 0.90 V. The absorption peak in visible spectral range displays an obvious hypsochromic shift. After 1422 switchings, the peak current in cyclic voltammogram and the absorbance of UV-Vis spectrum can retain nearly 83% and 60%, respectively, indicating that the composite films exhibit a reasonable cycle life.