Fiber, monolithic fiber and twisted fiber structures: efficient microwave absorption via surface-modified carbon nanotube buckypaper/silicon carbide-based self-sealing layered composites

The design of laminated structures is important for tuning the performance of microwave absorbing materials with integrated structures and functions, but still faces great challenges. Herein, a self-sealing layered structure that integrates a laminated structure and a self-sealing structure is proposed. In this work, CNT buckypaper (BP) was first helically convolved to obtain a three-dimensional (3D) self-sealing layered fiber. Subsequently, 3D CNT BP/silicon carbide (CNT BP/SiC) self-sealing layered (CSSL) substrates, i.e., fiber, monolithic fiber and twisted fiber structures, were prepared by changing the self-sealing layered fiber arrangement methods. Meanwhile, the impedance matching of the CSSL substrates was improved by using the SiC nanowire (SiC_nw) porous film as a cladding layer. The synergistic effect of good impedance matching and the self-sealing layered structure endowed the CSSL substrates clad with SiC_nw porous film (CSSLS) composites with excellent microwave attenuation properties. The minimum reflection loss values for the CSSLS with fiber, monolithic fiber and twisted fiber structures were −49.35, −50.77 and −55.02 dB respectively, and the corresponding maximum effective absorption bandwidths were 3.50, 3.50 and 3.99 GHz, respectively, in the X-band. The twisted fiber structure, which had the most complex structure, had the best microwave absorption properties.