Charge transport mechanism in dodecylbenzenesulfonic acid doped polyaniline/carbon black composites

Dodecylbenzenesulfonic acid (DBSA) doped polyaniline and carbon black (CB) composites (PANI-DBSA/CB) were synthesized by in-situ polymerization of aniline in the aqueous dispersion of carbon black (CB) in the presence of ammonium persulfate (APS) as an oxidant. Various composite samples with varying amounts of CB (1 wt% and 2 wt%) were synthesized and were characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). XRD studies confirmed the formation of the well-organized and semi-crystalline structure of the composites. SEM analysis revealed the increase in grain size and the granular structure of the synthesized composites. DC conductivity was measured in the temperature range from 300 K to 393 K using two probe methods. An increase in DC conductivity was found on the inclusion of carbon black at all temperatures and the most probable model of charge transport was found to be three-dimensional variable range hopping (3D-VRH). As the concentration of CB in the composites increased, activation energy was found to be decreased. The density of states, hopping length, and hopping energy were calculated, respectively, and were found to be influenced by CB incorporation.