Comparative study of pure polyaniline with various oxidants by a template free method

Polyaniline was successfully synthesized by a template-free method using APS (Ammonium peroxydisulfate), K2Cr2O7 (Potassium dichromate) and FeCl3 (Ferric Chloride) as oxidizers. The samples were characterized by structural, optical, morphological and electrical studies. The SEM images show the presence of spherical and flower-shaped particles with uniform size distribution. Optical studies indicate the presence of an absorption band around 285–350 nm due to π–π⁎ electronic transition in the benzene rings of the polymer backbone. The calculated band gap energy is found to vary 2.3–2.7 eV for the different oxidants used. The FT-IR spectrum confirms the presence of formational groups of PANI. XRD studies were also taken for the synthesized PANI. Photoluminescence studies reveal the direct band gap energy variation between 3.18 and 3.86 eV. Electrical studies exhibit the positive photoconductivity nature of the PANI samples. The maximum conductivity is observed for the PANI prepared with APS in the aqueous medium. The dielectric constant is very high at low frequency range and becomes stable at higher frequency.