Electrochemical synthesis of polyaniline film in supercritical carbon dioxide as a solvent

A conductive polyaniline (PAN) film was successfully synthesized in a homogeneous supercritical carbon dioxide (scCO₂)/acetonitrile (AN) system. The homogeneous supercritical state was confirmed by observations of the phase behavior of the system through a high-pressure cell with a viewing window. The flatness of the film in that system decreased with the further addition Of CO₂. This result suggests that the low viscosity Of ScCO₂ plays an important role in improving the transfer rate of solvent. The roughness of the film prepared in the homogeneous ScCO₂/AN system was reduced compared with that of the film prepared in dichloromethane itself as a solvent. The slow growth of the film and the high diffusion rate of the monomer seemed to account for the smooth and flat film formation.