Abstract: Poly(aniline) (PAn) was synthesized by chemical oxidation with (NH_4)_2S_2O_8 as oxidant, and the interface between PAn and an improved PEO-LiClO_4 complex was investigated using ac impedance technique. In the interface a salt-rich passiva-tion film arising from the self-diffusion of ClO_4~- anions exists. During film formation the thickness of the film may be expressed in terms of L=Kt~(0.14) where K is a constant related to the intrinsic properties of the film. The passivation film has an ionic conductivity of 2.2×10~(-6) S·cm~(-1) at 15 ℃, suggesting that it causes no unfavorable effect on the electrochemical reversibility of the PAn. The constancy of R_pC_p values with time implies that the storage time does not affect the structure or components of the passivation film during the thickening of the film. The relationship of temperature-conductivity, silimar to that observed in other amorphous PEO-MX complexes, can be described by VTF equation.

Key words: Ac impedance, Poly(aniline), Passivation film, Ionic conductivity