Ni ferrite highly organized as humidity sensors

Synthesis and characterization of nickel ferrite using polyacrylamide-based hydrogels as template agents for obtaining NiFe2O4 by the sol gel autocombustion method was studied, the investigation representing a novelty in the field. The polyacrylamide-based hydrogel used as a template agent, was synthesized by an original simultaneous polymerization-crosslinking method, using a monofunctional crosslinking agent. The ferrite was synthesized by the sol gel autocombustion method, using citric acid as a chelating/fuel agent. The as-obtained hydrogel was characterized by IR, SEM and thermogravimetric techniques, as well as swelling behavior. As-synthesized ferrites were characterized by IR, SEM, XRD techniques, as well as by electrical and magnetic properties. The electrical investigations were carried out in different humidity conditions in order to highlight the influence of humidity on electrical properties, in this respect the prepared NiFe2O4 with highly organized structure was tested for applications as humidity sensors. (C) 2015 Elsevier B.V. All rights reserved.