Development of polyaniline/polyimide composite as a heat resistant gas sensor

Abstract

Polyaniline (PANI)-based gas sensor was modified to be used at high temperature by dispersing PANI in an insulating polyimide (PI) matrix using a dry mixing method. The effect of acid dopant type, acid concentration and thermal stability on exposure of the modified sensor to CO gas was studied. At the fully doping level, the camphorsulfonic acid-doped PANI had higher specific conducctivity than the nitric acid-doped PANI, The conductivity response to CO, followed the power law = a[CO]b where the scaling exponent b characterizes the concentration dependence (d/dc). At increasing doping levels, the concentration dependence increased and the temporal response time became shorter. At high temperatures, the PANI/PI composite had greater concentration dependence than the doped PANI. The conductivity response correlated well with the morphology and thermal stability as determined by EA, FT-IR, EDX, UV-Vis, XRD, SEM and TGA.