Electroconducting polyaniline composite films prepared by chemical oxidative polymerization at gas/liquid interface

Electroconducting polyaniline composite films have been prepared by chemical oxidative polymerization at gas/liquid interface between heated aniline vapor and aqueous liquid membrane containing a water‐soluble matrix polymer and an oxidizing agent (and proton acid). The formed composite films are green, semitransparent and uniform. Conductivity, transmittance, and visible and IR spectra are investigated with the films prepared under various preparative conditions: aniline vapor exposure time, atmospheric and aniline temperatures, chemical species and concentration of the oxidizing agent, and concentration ratio of the proton acid to the oxidizing agent. The conducting composite films are formed with the liquid membrane containing above 680 mV of oxidation potential and some proton donor. The film conductivity is determined by the absolute amount of the radical cation structure component of polyaniline and the composition ratio of the radical cation component to the quinonediimine component of polyaniline, which is due to the oxidation potential and protonation effect of the liquid membrane. The excess proton acid coexisting with the oxidizing agent contributes to the film transmittance by uniform distribution of polyaniline in the composite film, aside from its contribution to conductivity by increase of the radical cation component at suitable concentration of the oxidizing agent.