Enhancing humidity sensing performance of polyaniline/water soluble graphene oxide composite.

The humidity sensing performance of Polyaniline/Water soluble graphene oxide [PWGO] composites have been presented in this work. Various mass ratios of Water soluble graphene oxide [WGO] were mechanically mixed with Polyaniline [PANI] prepared by in-situ polymerization process to form PANI / WGO composites. For the purpose of humidity sensing studies, the samples were structurally characterized by FTIR, Raman, XRD, SEM and TEM techniques and comparatively analyzed. The film of the samples prepared by deposition on ordinary glass substrate using cost effective spin coating technique were tested for their humidity sensing performance in the relative humidity (RH) range of 11-97%. Of the four composites studied, the PWGO-4 composite recorded a good response time of 8 s and a recovery time of 9 s and a very low humidity hysteresis. The mechanism for sensing has been explained on the basis of three sequential steps: chemisorption, physisorption and condensation process. The humidity sensing stability of the composites were tested over a period of 2 months.