Polyaniline-Titanium dioxide composite as humidity sensor at room temperature

In the present work, Polyaniline (PANI) and Polyaniline-Titanium dioxide (PANI-TiO$_2$) composite have been synthesized separately by chemical polymerization of aniline without/with TiO$_2$. Characteristic absorption bands of PANI and TiO$_2$ in the composite were confirmed by FTIR studies, indicating the interaction of PANI with TiO$_2$. Comparative study of XRD patterns of PANI and the composite confirmed superficial deposition of PANI on TiO$_2$ and the average size of the composite particle was found to be 25 nm. The aggregated granular porous morphology of the composite was confirmed by its SEM image. The composite's sensing response to humidity at room temperature was tested and was found to be 84.21 % in the range 25 % – 95 % RH. The response and recovery time of the composite at 95 % RH were measured to be 60s and 100s respectively and its sensing stability over a period of one month was also confirmed.