Cobalt/polypyrrole nanocomposites with controllable electromagnetic properties

Abstract

In this work, cobalt/polypyrrole (Co/PPy) nanocomposites were prepared via an in situ oxidation polymerization of pyrrole in an aqueous dispersion of Co nanoparticles (NPs). The Co/PPy nanocomposites showed good electromagnetic properties because of the coexistence of magnetic loss and dielectric loss to electromagnetic waves. The electromagnetic wave absorbing bandwidth (reflection loss < -10 dB) for Co/PPy (30 wt% in a paraffin matrix) was located at 11.7-16.47 GHz with a thickness of 2 mm, and with a maximum reflection loss (around -33 dB) at 13.6 GHz. More interestingly, the electromagnetic wave absorbing properties of the nanocomposites can be easily controlled by tuning the ratio of the two components in the composites. This improved electromagnetic wave absorption may be attributed to the excellent electromagnetic match at the corresponding resonance peaks for dielectric and magnetic loss. These magnetic nanoparticles/conducting polymer nanocomposites are great potential candidates for use as electromagnetic wave absorbents due to their excellent properties such as wide absorbing frequency, strong absorption, good compatibility, low density and controllable absorbing properties.

Investigation on electromagnetic characteristics, microwave absorption, thermal and mechanical properties of ferromagnetic cobalt–polystyrene composites in the X-band (8.4–12.4 GHz)

“…58,60,61 In the cobalt particles, the natural resonance and exchange resonance coexist, which can also be attributed to the magnetic loss. 52 The dielectric and magnetic loss tangents of Co-PS composites are shown in Fig. 11a and b, respectively.…”

Effects of carbon fiber modification with multiwall CNT on the electrical conductivity and EMI shielding effectiveness of polycarbonate/carbon fiber/CNT composites

“…As the use of electronic devices increases, research into electromagnetic wave shielding polymer composites is becoming more active . This is because the electromagnetic wave causes malfunctions of electronic devices, and harmful influences on the human body . There are three main types of electromagnetic shielding materials, which are metals, conductive polymers, and polymer composites .…”

Studies on Conduction Mechanism, Magnetization and Electrochemical Properties of Polythiophene-Cobalt Nanocomposites

“…Thermal conductivity increased in nickel doped polypyrrole composites [13]. Incorporation of cobalt in polypyrrole exhibited resistive switching and magnetism [14] and showed utility in the application of electromagnetic wave absorption [15]. Of the three prominent ferromagnetic metals, cobalt has always been considered to be special as it has high saturation magnetization and Curie temperature [16].…”