Structural and room temperature gas sensing properties of polyaniline/titania nanocomposite

Polyaniline-emeraldine (PE) and polyaniline/titania nanocomposites (PTNs) were prepared using an in-situ self-assembly chemical oxidative polymerization of aniline monomers in the absence and presence of different wt% of titania (TiO2) nanoparticles, respectively. The structural and morphological properties of the PE and PTNs were evaluated by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Moreover, PE and PTNs were deposited on an epoxy glass substrate with finger type Cu-interdigited electrodes as liquefied petroleum gas (LPG) sensor. A PTN sensor with 40 wt% TiO2 nanoparticles was exhibited the response value and the response/recovery time of 43.2% and 76/95 s, respectively, toward 0.4 vol% LPG concentration. Our handmade sensor exhibited excellent reproducibility and stability in period of 16 weeks with a small degradation of about 7%. The results of the sensing for different gases were revealed the sensor has an excellent selectivity to LPG gas. Furthermore, the factors affecting LPG sensing performance and plausible gas sensing mechanism are discussed.