Tunable microwave absorption and shielding effectiveness in the nanocomposite of 3D hierarchical flower-like Co3O4 and rod-like polyindole

Abstract

• 3D hierarchical composites of Co 3 O 4 /polyindole/paraffin were successfully prepared. • Electromagnetic properties of composites improved as the Co 3 O 4 /PIn ratio increased. • A 25 wt% Co 3 O 4 /PIn paraffined composite achieve RL = −21.5 dB and EAB = 3.5 GHz. • Total shielding effectiveness ( SE T ) was increased by the increase of Co 3 O 4 /PIn. • SE T of 25 wt% Co 3 O 4 /PIn paraffined composite was four times higher than 5 wt% one. Due to the rapid development of wireless electronic devices, achieving an excellent microwave absorber is crucial in modern life. The composite of flower-like Co 3 O 4 and rod-like polyindole (PIn) was embedded in the paraffin matrix for tunable microwave absorption performance and shielding effectiveness. Investigation of microwave absorption features of Co 3 O 4 /PIn paraffined composites in the X band frequency range revealed a good performance for 25 wt% Co 3 O 4 /PIn paraffined composite with reflection loss and an effective absorption bandwidth of −21.5 dB and 3.5 GHz (covered ∼ 83% X band). The pretty good microwave absorption performance of this composite originated from magnetic loss (by Co 3 O 4 ), dielectric loss (by PIn), and heat transfer capability (by paraffin). Shielding effectiveness was also increased with the increase of Co 3 O 4 /PIn loading percentage, with a total shielding effectiveness of 28.1 dB with the most contribution from shielding effectiveness for absorption. This work provides an easy and low-cost approach for tunable microwave absorption and shielding effectiveness for practical applications.