Polyaniline (PANI) composite films were prepared from aniline monomers by in situ polymerization, acid-doping and layer-by-layer self-assembly through the electrostatic force. The progress of polymerization was monitored by temperature and color changes of chemically active aniline aqueous solution. The UV-vis spectra of the PANI composite films prepared at various polymerization stages were detected, from which the preliminary mechanism of the film formation was studied. It was proposed that the self-assembly of polyaniline occurred through the quick absorption of aniline monomer cations or aniline monomer cation radicals on the glass surfaces by electrostatic attractions to form homogeneous polymerization centers, and then the chain grows to polyaniline. The polyaniline which was doped under acidic condition, carried positive charge to absorb anionic sodium polystyrene sulfonate (PSS), and it thus recycled to layer-by-layer self-assembly multilayer polyaniline composite films.

Key words: polyaniline composite film, layer-by-layer self-assembly, in situ polymerization, mechanism of film formation