Polyaniline/Semiconductor Oxide Composites Synthesis And Gas-Sensing Properties

Metal oxide semiconductor materials(such as SnO2、ZnO et.al) are widely used in gas sensors,but there are also many problems in the application, such as that poor selectivity, the stability is not very well and high working temperature and so on. In recent years,conducting polymers such as polypyrrole,polythiophene,polyaniline and so on and metal oxide material composites exhibit excellent performance in the gas-sensitive detection subject to the attention of researchers.In this paper, the preparation of pure polyaniline and polyaniline/nano-semiconductor oxide(TiO2、In2O3)composite materials by chemical oxidative polymerization and interfacial polymenization methods.Absorption spectrum of prepared materials were analyzed by FT-IR respectively,the structures of prepared materials were analyzed by XRD,and microstructure of prepared materials were characterized by SEM.The gas-sensing properties of PANI/semiconductor (TiO2、 InO3) composite materials and single PANI were tested by static test system of gas sesors.The results show that:through the chemical oxidative polymerization to prepare polyaniline,sulfosalicylic acid(SSA)as the protonic acid,sodium dodecyl sulfate (SDS) as the surfactant,it has good gas-sensing properties and high selectivity to ammonia at room temperature,and almost have no response to toluene,actone,ethanol, methane, liquefield petroleum(LPG). PANI-SDS/TiO2composites which prepared by in situ polymerization have better sensitivity and stability to ammonia than that of the pure PANI.By interfacial polymenization,sulfosalicylic acid as the proton acid synthesized the polyaniline,then by mechanial ball milling method,the PANI/TiO2、PANI/In2Os nanocomposite materials were prepared.By detecting gas sensing properties of composite materials and found that,compared with the pure PANI, the PANI/TiO2、 PANI/In2O3nanocomposite materials sensitivities、selectivitives and stabilities has varying degrees of improvement.