Enhanced sensor functionality of in situ synthesized polyaniline–SnO2 hybrids toward benzene and toluene vapors

Abstract

Polyaniline–SnO2 (PANI–SnO2) hybrid materials with varied SnO2 content were prepared by in situ chemical oxidative polymerization method. The prepared materials were characterized by FTIR, XRD, TGA, DSC and SEM analyses. The dielectric constant of the hybrid materials was calculated via Nyquist plot of the AC impedance analysis. Sensor functionality of the hybrids was studied toward benzene and toluene vapors in dry N2 atmosphere at room temperature. The response of the materials was presented in terms of their normalized conductivity change in per cent. The PANI–SnO2 hybrid with 40wt% SnO2 exhibited the maximal response toward both benzene (16.9%) and toluene (19.5%) vapors. In situ synthesis technique enhanced the conductivity and response of the PANI–SnO2 materials in comparison to the physical mixture. This is attributed to the formation of greater number of p–n heterojunctions through large surface interaction of the analyte species. The hybrids showed slightly higher response toward toluene than benzene.