Highly conductive polyaniline/graphene nano-platelet composite sensor towards detection of toluene and benzene gases

High-performance gas sensors operating at room temperature are in great demand towards monitoring the environmental hazardous pollutants such as toluene and benzene. In this work, we report synthesis of polyaniline–graphene nano-platelets (PANI–GRNPs) hybrid composites with varied content of GRNPs in PANI matrix by in situ chemical oxidative polymerization. Structural and morphological characterization of polymer nanocomposites were investigated through scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR). SEM micrograph of polymer nanocomposite reveals uniform distribution of GRNPs in the PANI matrix. FTIR analysis of PANI–GRNPs composite revealed the presence π–π interaction between PANI and GRNPs leading to the formation of charge-transfer complex. The electrical properties of the prepared composites were tested as a function of GRNPs content in PANI matrix, the presence of GRNPs has significantly improved the conductivity and dielectric response of polymer nanocomposite in comparison to pure PANI. The sensor devices fabricated using PANI–GRNPs composite were tested for non-polar toluene and benzene vapors at ambient temperature using laboratory-made sensor setup. PANI–GRNPs composites used in the present investigation have shown enhanced sensitivity for toluene and benzene gases in comparison to pure PANI. Due to excellent sensitivity, faster response and recovery time, these PANI–GRNPs composites may find extensive technological applications as a conductometric sensor towards detection of toluene and benzene gases at lower concentrations.