▎ 摘　　要

A new structure of a polymer composite was designed to be used as a vapor sensor for detection of a set of volatile organic compounds (VOCs), namely ethanol, methanol, isopropyl alcohol (IPA), toluene and water as moisture in the atmosphere. Picric acid was used for physical decoration of graphene (Gr), as a conductive filler, and then, the modified graphene (Gr.PA) was added to polyvinyl alcohol (PVA) to design a conductive polymer composite (CPC) sensitive layer for detection of polar vapor analytes. The Fourier transfer infrared spectroscopy (FTIR) was used to study the physical adsorption of picric acid molecules on the surface of Gr. The experimental results revealed that the sensitivity of the prepared CPC transducer was dramatically improved through the decoration of Gr surfaces with PA molecules. The enhanced sensitivity was related to the addition of -OH and -NO2 functional groups on the surface of Gr (due to picric acid molecules). Those polar functional groups increased the diffusion driving force of polar analytes into the polymer composite. On the other hand, upon adding PA molecules, Gr-Gr junctions were tuned as sensitive sites, and the adsorbed vapor molecules increased the distance of Gr platelets, which, consequently, decreased the electron tunneling conductivity of the prepared CPC. The experimental results also proved that one could change the electrical conductivity of Gr as a p-type semiconductor through adsorption of analyte molecules on its surface. All in all, the attained results demonstrated that tuning the conductive filler junctions could be regarded as an exceptional strategy to improve the sensitivity of CPC transducers.