Expanded graphene-oxide encapsulated polyaniline composites as sensing material for volatile organic compounds

The expanded graphene-oxide (EGO) encapsulated PA composite materials are prepared by in-situ chemical oxidative polymerisation polyaniline (PA) where polymerization of aniline was carried out in presence of EGO using ammonium-persulphate in an acid medium. The synthesized samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrical conductivity measurements. The electrical conductivity get increases with temperature showing semiconducting behaviour and the conductivity is found to be 101.04 S/m at 413 K. The composite materials are exposed with various concentrations of vapours of different volatile organic compounds (VOCs) such as acetone, chloroform and carbon tetrachloride and compared with the pristine polymer. The oxidising VOCs like acetone on exposure to pristine polymer and PA/EGO composite is found to be decrease in resistivity by hydrogen bonding with the redox cites of the polymer. Among these VOCs, the sensitivity towards chloroform is found to be more in PA and its composites than the other two compounds.