Polyamide-12/polyaniline layered composite films: Specificity of the formation and Raman spectroscopy investigation

Composite polyamide-12/polyaniline (PA-12/PANI) films were prepared by a treatment of PA-12 films swelled in aniline with a water solution of ammonium persulfate (APS) and HCl. The existence of a very thin (2 mu m) subsurface PANI containing layer in the composite film was shown by confocal micro-Raman resonance spectrometry. A combination of the micro-Raman and UV-Vis measurements allowed determining the PANI concentration in this conductive layer. This approach allowed studying the kinetics of the matrix polymerization process. It is shown that this solid phase process has the strong kinetic specificity as compared with known solution based systems. It is suggested that this is due to not only the physical-chemical interactions of aniline and formed PANI with amide groups of the matrix but also to a physical state of aniline localized in voids of the free volume of the matrix and to formation of the additional oxidant HOCl in the oxidizing solution.