Polyaniline-SnO$_2$ Nanocomposites for Better Sensitivity of NO$_{\mathrm{X}}$ gases at Lower Temperatures

We demonstrate that the sensor based on Polyaniline (PAni) nanofibers, simply prepared by the interfacial polymerization, has advantages of sensitivity, spatial resolution and rapid time response for NO$_2$ gas at room temperature. Although PAni is one of the most studied conducting polymers due of its good electrical conductivity, environmental stability and relative easier synthesis, yet due to poor solubility of PAni, it is difficult to form the film adopting conventional methods. Nonetheless, nanomaterials of conjugated polymers are found to exhibit superior performance as compared to conventional materials due to their larger exposed surface area. The objective of this work is to study the PAni doped SnO$_2$ nanocomposite as novel sensing system and to probe the NOx sensing characteristics of this sensor at room temperature. Here we focus on the effect of doping ratio of sensor material, gas flow time and response time. PAni with different amounts has been stirred with SnO$_2$ solution to obtain SnO$_2$/PAni mixture. In present work, sensors with different PAni doping ratio were prepared and characterized so as to ascertain the favorable conditions for higher sensitivity, selectivity and better gas sensing characteristics. The as-grown films characterized employing various techniques and revealed that PAni/SnO$_2$ nanocomposite show good gas sensitivity at 30-100 $^{\circ}$C.