ABSTRACT
In this work, polyaniline (PANI) synthesized by in-situ polymerization was mechanically mixed with different feeding mass ratios of Y2O3 to form four Polyaniline/Yttrium oxide (PYO) composites. Among them, the PYO-4 composite acquiring nanorod structure with high aspect ratio confirmed from its TEM image and consequent maximum enhancement in its humidity sensing response discussed in comparison with those of PANI and other composites. The interaction of PANI with Y2O3 in the composite confirmed from FTIR studies. The increase in defects and vacancies in all the composites, being maximum in PYO-4 composite nanorods compared to those of PANI confirmed from XRD studies. Maximum increase in the porosity of PYO-4 composite nanorods as compared to those of PANI and other composites confirmed from SEM studies. The humidity sensing studies revealed that, PYO-4 composite nanorods showed a maximum sensing response of 99.99% with a dynamic response and recovery time of 3 s and 4 s respectively. The PYO-4 composite nanorods having acquired comparatively good sensing characteristics such as low real sensitivity and limit of detection (LOD), negligible hysteresis, best linearity and perfect stability as against those of PANI and other composites established which were also correlated with the calculated physical parameters such as porosity, water content and degree of swelling.
ABSTRACT
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 8â¯s and a recovery time of 9â¯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.
