237-244This 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 PANI 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 <i style="mso-bidi-font-style:
normal">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 PANI 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 PANI yielding
characteristically different hybrid materials