Biologically Inspired Nanoporous PAN/PMMA/β-CD Carbon Fibers for Efficient Microwave Absorption

One-dimensional carbon nanofibers (CNFs) have great potential as lightweight wave absorbers due to their excellent plasticity and stability. However, a high electrical conductivity tends to generate massive reflected waves on the surface of these absorbers. Therefore, the microwave absorption properties need to be modulated by rational microstructural design and heterogeneous interface construction. In this paper, lotus-rootlike multichannel CNFs (polyacrylonitrile/poly(methyl methacrylate)/β-cyclodextrin (PAN/PMMA/β-CD)) were prepared by sacrificial template-assisted electrospinning, followed by a traditional stabilization and carbonization process. The introduction of a multichannel structure together with the overlapping conductive network formed in CNFs not only greatly improves the dielectric loss ability of the material but also provides more pathways for electron transfer. Effective tuning of the channel structure and conductivity of the material can be easily achieved by adjusting the sacrificial agent content and the carbonization temperature. The sample (MC–CNFs-1:1–900) shows good impedance matching characteristics and microwave attenuation when the content of the sacrificial agent in the precursor filament is 50 wt % with the carbonization temperature set at 900 °C. Hence, a minimum reflection loss (RLmin) of −45.19 dB at 2.8 mm and an effective absorption bandwidth (EAB) of 3.825 GHz were achieved for CNFs by a simple method of preparation, providing a solid foundation for the development of high-performance lightweight microwave-absorbing materials (MAMs).