Effect of Cobalt Aluminum Oxide Nanoparticles on the Structural, DC Conductivity and Humidity Sensing Properties of Polypyrrole

• Published in: Journal of macromolecular science. Physics Vol. 59; no. 12; pp. 821 - 835
• Main Authors: Sutar, R. A., M. V., Murugendrappa
• Format: Journal Article
• Language: English
• Published: New York Taylor & Francis 21.08.2020; Marcel Dekker, Inc
• Subjects: Aluminum; Aluminum oxide; Cobalt; cobalt aluminum oxide; Conduction; Conductivity; dc conductivity; Energy bands; Energy dispersive X ray analysis; Energy gap; Humidity; humidity sensor; Low temperature; Nanocomposites; Nanoparticles; polypyrrole; Polypyrroles; Properties (attributes); Scanning electron microscopy; Spectroscopy; Transmission electron microscopy; X ray analysis; X-ray diffraction
• ISSN: 0022-2348; 1525-609X
• DOI: 10.1080/00222348.2020.1807691

An in-situ chemical polymerization method maintaining a low temperature in the range of 0-5 °C was used to synthesize nanocomposites with different weight percentages of cobalt aluminum oxide (CAO) in polypyrrole (PPy). Structural, morphological, elemental, and particle size characterizations were done by employing X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM), respectively. The XRD analysis revealed the amorphous nature of pure PPy and the crystalline peaks of CAO along with the diminishing amorphous peak of PPy for the PPy/CAO nanocomposites. The SEM and TEM studies of PPy and PPy/CAO nanocomposites in powder form showed aggregates of the spherical particles with individual particle sizes of around 500 nm for pure PPy and in the range of 120-210 nm for the nanocomposites. The energy band gaps for pure PPy and the nanocomposites were analyzed by UV-VIS spectroscopy and were such that they can be considered for wide bandgap applications. Characterization of the temperature variation of the dc conductivity was carried out for all nanocomposites and found to be of the semiconductor type conduction. The humidity sensing properties of the pure PPy and its nanocomposites were studied and an improvement in the sensing properties of PPy by the addition of CAO was found.