Hierarchical composites of polypyrrole/graphene oxide synthesized by in situ intercalation polymerization for high efficiency and broadband responses of electromagnetic absorption

Hierarchical graphene oxide/polypyrrole composites were fabricated by initiating an in situ intercalation polymerization of pyrrole into the interlayers of graphite oxide . It was interesting that a chemical hybridizing group of HN–CO could be verified inside the graphene oxide layers during the exfoliation of graphite oxide, resulting in a new kind of graphene oxide based composites with highly crumpled structures. This intercalation compounding technique made the composite display much stronger polarization, leading to notable enhancement in electromagnetic loss with broadband responses. As an example of the 2.96 mm thickness sample, the rock-bottom on the reflection loss curve was low to −58.1 dB at 12.4 GHz and the bandwidth below −10.0 dB could be as wide as 6.2 GHz, which was remarkable superior to those of the pure graphite oxide as well as other hybrids of graphene oxide that had ever been reported. The improvement in absorbing capacity arose from the unsymmetrical groups generated from the chemical hybridization, which could lead to multi-scaled polarization relaxations. In addition, the three-dimensional intercalated network would lead to synergistically benefit of impedance matching and interfacial relaxation loss. These results provided a new strategy to prepare graphene-like composites for functional design such as high-efficient microwave absorbent.