Synthesis and characterization of electromagnetic properties of polypyrrole nanorods prepared via self-reactive MnO2 template

• In the present work, morphology effect of PPy nanorods on the microwave absorbing properties is investigated for the first time.
• Polypyrrole nanorods were successfully synthesized, using assembled α-MnO2 nanorods as oxidizing agent and self-reactive templates.
• In this preparation method, the MnO2 nanorods served as both oxidative polymerization initiator and physical template.
• The morphology of PPy nanostructures are totally inherited from the MnO2 templates.
• Polypyrrole morphologies significant factor which will effect on the dielectric properties of PPy nanostructures and consequently affects the microwave absorption property of PPy.

Intrinsically conducting polymers (ICPs) due to special properties are promised in various applications, especially for radar absorbing materials (RAM). In the present paper, the dielectric and microwave absorbing properties of polypyrrole nanorods (PPyNR)/paraffin composite have been investigated in the frequency range of 2–18 GHz, for the first time. Also a simple route was successfully used for the chemical synthesis of PPy via a reactive template of α-MnO2. For this purpose, the reactive template of MnO2 was prepared by a facile hydrothermal method at 150 °C. The synthesized α-MnO2 was used as oxidizing agent for polymerization reaction of PPy. The XRD patterns confirmed that the MnO2 template consumed as an initiator almost completely. In the SEM images, the α-MnO2 sample was composed of uniform nanorods and the PPy nanostructures were inherited their morphologies from the MnO2 templates. Microwave absorbing studies of PPyNR/paraffin composite indicated the remarkable EM wave absorption property with the maximum reflection loss (around −50 dB) at about 10 GHz at a thickness of 3.1 mm. Microwave absorption result showed that these nanocomposites had excellent intrinsic potential for various microwave absorbing applications.