Hierarchical architecture bioinspired CNTs/CNF electromagnetic wave absorbing materials

One dimensional carbon nano material has attracted extensive attention in the field of electromagnetic wave (EMW) absorption due to its large aspect ratio, ultrafine nano networks, good thermal stability and designable surfaces. However, one-dimensional nanomaterials are easy to agglomerate, loss and impedance are mismatched, which seriously restricts their application. How to overcome the agglomeration of one-dimensional nanomaterials, as well as design nano-interface and precisely control the dielectric loss are the key to the research of EMW absorbing materials. Inspired by the dense and regular hierarchical structure of pine branches, we use carbon nano fiber (CNF) converted from bacterial cellulose (BC) as the matrix, and in situ growth amorphous carbon nanotubes (CNTs) on its surface, so as to construct a hierarchical architecture similar to pine leaves in nanoscale, which not only solves the common aggregation problem of one dimensional nanomaterial, but also obtains stronger interface polarization capability through hierarchical nano structure. Furthermore, the amorphous CNTs network have moderate conductivity, which does not lead to impedance mismatch. The reflection loss of CNTs/CNF with a CNTs content of 63.2 wt% can reach −68.2 dB at a thickness of 2.7 mm, and the maximum effective absorption bandwidth reaches 5.5 GHz. The design strategy of hierarchical amorphous carbon nanocomposite integrates strong EMW absorption and good impedance characteristics, the synthesized CNTs/CNF composites exhibit excellent EMW absorption properties.