Abstract:The preparation of PANI/PAA composite films was carried out by the direct polymerization method and the layer by layer method. The surface structure and the composition of the composite films were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR); the cyclic voltammetry (CV), the current response characterization (CA) and the electrochromic characterization were also mensurated. It was found that SEM and FT-IR results showed that these were only one difference in the material structure of the PANI/PAA composite films synthesized by the two methods; the PANI/PAA composite film synthesized through the direct polymerization method (PANI/PAA-DP) had a larger particles size, two clear oxidation and reduction peaks, the response times for reduction and oxidation were 120 ms and 226 ms, the transmittance modulation of the PANI/PAA composite films reached 10% at 600 ~ 700 nm; the PANI/PAA composite film synthesized through the layer by layer method (PANI/PAA-LP) had a porous network structure, three clear oxidation and reduction peaks, stable electrochemical property, improved electrochromic performance, the response times for reduction and oxidation were 67 ms and 45 ms, the transmittance modulation of the PANI/PAA composite films reached 40% at 600 ~ 700 nm, respectively.