Study of FTIR Spectra and Effect of Transitions on Conductivity of Polyaniline Synthesized Using Different Dopants by Chemical Oxidation

Abstract

This article reports the synthesis of Polyaniline (PANI) in emeraldine form (EB) by in-situ chemical oxidation method using different dopants and ammonium persulphate (APS) as an oxidant. The samples were characterized by FTIR, UV-Vis, and their conductivity determined by four-point probe method. Quinoid and benzenoid bands at 1553-1596 cm^-1 and 1437 – 1496 cm^-1 respectively where observed in all the samples. The band gaps and conductivity values for all the bulk samples were obtained using the absorption spectra and Stern relation. It was found that the transition Ï€ i- iÏ€* iforiPANI-H₂SO_{4 i}occurs iearlier ithan iin iPANI-HCl isample.i This ican ionly ibe ias ia iresult iof ithe iH₂SO_{4 i}acid ibeen ia istronger iacid ithan ithe iHCl iand ias ia iresult ithe itransition ifrom iÏ€ i- iÏ€* irequired ilower swavelength ifor iPANI-H₂SO_{4 i}sample ias icompared ito ithe iPANI-HCl isample.iBy icomparing ithe ifour isamples ithe iÏ€ i- iÏ€* itransition ithen ican ibe iarranged ifrom ithe istrongest ito ithe iweakest ias iPANI-H₂SO_{4 i}followed iby iPANI-HCl ithen iPANI-HNO_{3 i}and ithe iweakest ibeing iPANI-CH₃COOH. The same trend is also observed for electrical conductivity of these samples.