Elaborate Structural Design of Polypyrrole-Based Microwave Absorbers: Synthesis, Enhanced Dielectric Characteristics, and Superior Absorption Capability

Intrinsically conductive polymers are expected as an advanced microwave absorption material due to their adjustable dielectric characteristics and low density. In this investigation, polypyrrole (PPy) with spherical aggregation and nanofiber structures were successfully synthesized by chemical oxidation polymerization strategy. The impact of reaction conditions on the structure, morphology, size, and chemical constituents has been investigated. The results indicate that the strong interfacial interaction between dopamine and pyrrole monomer leads to the formation of nanofibers. Because of the synergistic effect of favorable impedance matching, improved dielectric loss, and conductive loss, the PPy aggregations with nanosized particles exhibit outstanding absorption capability. At 6.32 GHz, the minimum reflection loss even reaches -46.73 dB. The effective absorption bandwidth (EAB) covers a broad frequency range of 6.51 GHz. Our work provides a versatile strategy for PPy-based materials with elaborately structural design to achieve excellent and modulated microwave absorption capability.