Polypyrrole/magnesium oxide composite as room temperature operable humidity sensor

Abstract

In the present research work, the humidity sensing performance of Polypyrrole/Magnesium oxide (PMGO) composite is reported. The Polypyrrole (PPy) was synthesized by chemical oxidative polymerization method and is mechanically mixed with Magnesium oxide (MgO) in the feeding mass ratio of 0.90:0.10. The prepared composite were characterized by XRD and FTIR technique. For the humidity sensing studies the film of the PMGO composite was prepared by depositing the sample on the ordinary glass substrate by simple, cost effective spin coating technique. The PMGO composite prepared shown a best sensing performance of 99.84% and has shown a quick response and recovery timing of 11 s and 22 s respectively. It also showed a good real sensitivity, limit of detection (LOD), linearity, hysteresis and good sensing stability over a period of two months. The porosity in case of PMGO composite has been investigated to be higher than that in case of PPy. The humidity sensing mechanism has been understood to be due to the formation of chemisorption and physisorption layers followed by capillary condensation process.