Zinc ferrite @ polyindole nanocomposites: Synthesis, characterization and gas sensing applications

This research work deals with the synthesis and characterization of polyindole (PIN)/zinc ferrite (ZnFe2O4) nanocomposite. In situ polymerization of indole with different contents of ZnFe2O4 nanoparticles has been employed in the work. Structural, morphological, thermal, gas sensing and electrical properties of the prepared composites have been evaluated. The shifting of peaks in the Fourier transform infrared and ultraviolet-visible spectrum has been found to reveal the interaction of ZnFe2O4 nanoparticles with the PIN matrix. Crystalline nature of the nanocomposites resulting from the presence of crystalline ZnFe2O4 has been revealed by X-ray diffraction studies (XRD). Scanning electron microscope and high-resolution transmission electron microscopy images revealed the uniform dispersion of nanoparticles at lower loading while at 15 wt% there are particle agglomerations. Improved thermal stability with the addition of ZnFe2O4 nanoparticles in PIN has been confirmed by thermogravimetry while the enhancement in glass transition temperature of the nanocomposite with respect to pure polymer has been confirmed by differential scanning calorimetry. The addition of nanoparticles greatly enhanced the alternating current and direct current conductivity, the dielectric constant and dielectric loss of PIN. The composite with 7 wt% shows the maximum properties. The fabricated composites showed excellent sensitivity and fast response to ammonia gas at room temperature. Thus the study reveals that the PIN/ZnFe2O4 nanocomposites can be considered as a potential candidate for the applications in sensors and nanoelectronic devices. POLYM. COMPOS., 40:2802-2811, 2019. (c) 2018 Society of Plastics Engineers