Optical, structural and conductivity properties of ferrous sulfate doped polyaniline

Abstract

Conducting polyaniline -ferrous sulfate composite was prepared by the chemical oxidative polymerizing method by adding different weight % of finely powdered ferrous sulfate salt during polymerization of polyaniline. The oxidative polymerization of aniline is carried out by using ammonium persulfate as an oxidant. The synthesized PANI/FeSO4 composites were characterized with FTIR, XRD, SEM, DSC, UV–Vis., and discussed conducting properties. FTIR characterization is done in KBr medium, the results reveal the formation of polyaniline composite with ferrous sulfate. XRD characterization shows a decrease in the crystallinity of the PANI composite with an increase in dopant concentration and morphology also observed to change with dopant as revealed by the SEM images. Based on Differential Scanning Calorimetry (DSC) profiles one can see clear evidence for the insertion of the salt in the polymer matrix. The variation of band gaps with dopant concentration is studied using UV– Visible spectroscopy, which shows that both direct and indirect band gaps of the doped PANI decrease with increase in dopant concentration. The conductivity of PANI composite is found to increase with an increase in the concentration of the salt. These results show that doping with FeSO4 is a very effective technique for altering the electrical and optical properties of PANI.