Fabrication of polyaniline/graphene oxide composites for implementation in humidity sensing

This work reports the measurement of impedance variations under various humidity conditions at frequency ranges between 100 Hz and 5 MHz. An electrochemical polymerization process has been used in the synthesis including varying the mass ratios of graphene oxide (GO) in polyaniline. An electrochemical deposition method has been used to produce a sample film on an indium tin oxide glass slide. The percentage relative humidity (RH%) of the samples has been estimated to be 20-90%. Impedance and humidity had an inverse relationship, i.e. the impedance value decreased with an increase in humidity. In contrast with platinum capacitive humidity sensors (HS), the GO-based HS had a sensitivity of 75-99%, which was ~10-fold more than that of traditional sensors. With three different parameter weight % of GO, the frequency range have been 100 Hz to 5 MHz and RH% has been found to 20-90%. The HS showed a fast response and recovery time. Therefore, GO appears to be a useful material for building HS with high sensitivity for a comprehensive approach.