Hybrid composite materials of anatase titania and conducting polyaniline: properties and chemical sensor application

This paper reports the investigation on synthesis, properties and chemical sensor application of polyaniline (PANI) - anatase titania (TiO2) hybrid composite materials prepared in the presence and absence of the soft template poly (vinyl alcohol) (PVA). FTIR spectroscopy reveals that PVA favors oxidation of large amount of aniline during PANT synthesis and causes production of more number of quinoid groups than benzenoid, but TiO2 maintains an equal level of quinoid and benzenoid. XRD study shows that PVA influences the d-space and crystallite size more in PANI-PVA and less in PANI-TiO2-PVA composite. In morphology, PANI-TiO2 has submicron particles and shows less agglomeration while PANI-TiO2-PVA has extensive agglomeration and surface smoothness. In chemical sensor application, PANI senses CH3OH vapor with a decrease of its conductivity and with an efficiency of 56%. However, with the inclusion of TiO2 or PVA, the sensor efficiency of PANT is shifted from CH3OH to CH2Cl2. Interestingly with both TiO2 and PVA inclusion, the material PANI-TiO2-PVA turns back its maximum sensor efficiency towards CH3OH but with an increase of its conductivity. All these results suggest that TiO2, PVA and TiO2-PVA exert different tuning roles on PANT yielding characteristically different hybrid materials.