In situ infrared ellipsometric monitoring of the growth process of polyaniline thin films and doping with poly(4-styrenesulfonate)

In this work, different undoped and doped polyaniline (PANI) films were synthesized by electrochemical pulse deposition. The growth process was in situ investigated using a combined infrared spectroscopic ellipsometry (IRSE) and optical spectroscopy set-up in the visible spectral range [Vis-ellipsometry and reflectance anisotropy spectroscopy (RAS)]. A growth acceleration effect and thicker PANI films in the presence of poly(4-styrenesulfonate) (PSS) are concluded from the measurements in the infrared and visible spectral range. IR-microscopic spectra revealed a strong inhomogeneity of the obtained PANI film doped with PSS. Moreover, the interpretation of the in situ IR ellipsometry spectra not only delivered qualitative (e.g., chemical structure and composition) information, but also quantitative information (e.g., film thickness) in the growth process of the PANI films by applying an optical layer model.