Characterization of the electrical conductivity and chemical properties of camphorsulfonic acid protonated polyaniline/poly(vinyl acetate) composite films

Abstract

In this study, the electrical conductivity of polyaniline (PANI)/polyvinyl acetate (PVAc)/camphorsulfonic acid (HCSA) composite films was investigated. The films were prepared via spin coating. Intrinsic insulating PVAc was thought to decrease the conductivity of the composites, however, the presence of PVAc led to an unusual increase in conductivity when the HCSA/PANI weight ratio was lower than 1.50 within certain PVAc concentration range. PANI/PVAc/HCSA films exhibited a maximum electrical conductivity of 1.65 S/cm at a PVAc concentration of 40 wt % along with the HCSA/PANI weight ratio of 1.25 compared to 0.5 S/cm of PANI-ES films at the same HCSA/PANI weight ratio. The chemical structure was analyzed by FTIR and XPS to investigate the unusual phenomenon. Hydrogen bonding interactions between the –NH groups of PANI and the –OOCCH3 groups of PVAc were found to have an impact on the charge density transfer and polarization of N atoms in PANI, thus affecting the protonation level and improving the conductivity of composite films. Moreover, PANI/PVAc composite films exhibited porous and amorphous structures. Therefore, PANI/PVAc composite films with high electrical conductivity and porous structures may be promising candidates for applications in biosensing.