Electrochromic behavior and stability of polyaniline composite films combined with prussian blue

The electrochromic behavior of polyaniline–poly(vinyl alcohol) composite films (CPAn–PVA) combined with electrochemically synthesized Prussian blue films (PB) was investigated in LiClO₄? CH₃CN nonaqueous aprotic solution. The combination was achieved by chemical deposition of CPAn–PVA on PB. When the combined films (CPAn–PVA–PB) are prepared with the appropriately low quantity of PB, CPAn–PVA–PB showed various visible absorption spectra overlapped roughly with the absorption of the component materials at different applied potentials. CPAn–PVA–PB provided the color change from green to blue at much lower applied potential than did CPAn–PVA. However, the combined PB eliminates protons from the first oxidized polyaniline chains to decrease the electrochemical activity of polyaniline. Therefore, to construct multicolor electrochromic devices by the combination of polyaniline with the other electrochromic materials, it is necessary to select the materials containing no deprotonation activity. © 1994 John Wiley & Sons, Inc.