Polyaniline specimens, emeraldine sulfate, emeraldine hydrochloride, and emeraldine base, were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, elastic peak electron spectroscopy, and density measurements using helium pycnometry. This work has been stimulated by a considerable interest in potential technological applications of polyaniline. The chemical state of polyaniline has been verified with infrared spectroscopy. X-ray spectroscopy was used for the qualitative and quantitative surface composition analysis of studied samples. The inelastic mean free path of electrons has been determined from the measurements of the elastic electron backscattering probability. This is one of the most frequent applications of elastic peak electron spectroscopy. The inelastic mean free path is needed for the quantitative analysis of polyaniline surface using electron spectroscopies. The method of elastic peak electron spectroscopy utilizes the theoretical model of the electron transport, accounting for the multiple elastic scattering events in the studied material. The inelastic mean free path values have been measured in the energy range 400-1600 eV. The resulting dependence has been compared to the values obtained using the G1 predictive formula of Gries.