Synthesis of aniline and aniline copolymer?s thin films by plasma polymerization technique and their characterizations

At the scope of this thesis aniline and aniline-containing copolymer thin films were obtained using the technique of double-discharge plasma. Aniline monomer used to produce thin films on quartz glass at room temperature, without addition of any solvent, at 1.5 kV DC voltage, 19 kV pulsed voltage and under 0.5 mbar pressure the plasma polymerization was applied. The optical energy band gap values of the fabricated PANI thin films was decreased with iodine doping. The copolymer thin films were obtained by employing aniline+thiophene and aniline+pyrrole monomers.The FTIR spectroscopy was used to investigate the structural properties, the UV-Vis spectroscopy was employed to determine the optical properties, the XPS spectroscopy was used to determine the elemental composition, and SEM was used to study the morphology of the produced thin films.The chemical structure of the thin films which is synthesized by using double-discharge plasma technique are differ from that of the one produced by other methods. The FTIR results revealed that the fragmentation occured during plasma polymerization process, besides the aniline structure an aliphatic structures also observed such as methyl, and methylene (CH2, CH3). The energy band gap values of PANI thin films measeured as in between 3.5 - 3.8 eV, and the iodine doped one are in between 2.7 - 2.2 eV. The obtained energy band gaps of the as-grown aniline-containing copolymer thin films are between 3.1 to 2.1 eV. The aniline-containing copolymers and the iodine doped thin films are showed semi-conductive characteristic. In addition, the produced thin films on quartz substrates placed in three different regions in the experimental system, exhibit differences due to variation of the plasma energy and particle density.Key Words: Plasma polymerization, Double discharge plasma technique, PANI thin films, copolymers