Architecting functionalized carbon microtube/carrollite nanocomposite demonstrating significant microwave characteristics

Abstract

Biomass-derived materials have recently received considerable attention as lightweight, low-cost, and green microwave absorbers. On the other hand, sulfide nanostructures due to their narrow band gaps have demonstrated significant microwave characteristics. In this research, carbon microtubes were fabricated using a biowaste and then functionalized by a novel complementary solvothermal and sonochemistry method. The functionalized carbon microtubes (FCMT) were ornamented by CuCo ₂S ₄ nanoparticles as a novel spinel sulfide microwave absorber. The prepared structures illustrated narrow energy band gap and deposition of the sulfide structures augmented the polarizability, desirable for dielectric loss and microwave attenuation. Eventually, the architected structures were blended by polyacrylonitrile (PAN) to estimate their microwave absorbing and antibacterial characteristics. The antibacterial properties against Gram-negative Escherichia coli ( E. coli) and Gram-positive Staphylococcus aureus ( S. aureus) were scrupulously assessed. Noteworthy, the maximum reflection loss (RL) of the CuCo ₂S ₄/PAN with a thickness of 1.75 mm was 61.88 dB at 11.60 GHz, while the architected FCMT/PAN composite gained a broadband efficient bandwidth as wide as 7.91 GHz (RL > 10 dB) and 3.25 GHz (RL > 20 dB) with a thickness of 2.00 mm. More significantly, FCMT/CuCo ₂S ₄/PAN demonstrated an efficient bandwidth of 2.04 GHz (RL > 20 dB) with only 1.75 mm in thickness. Interestingly, FCMT/CuCo ₂S ₄/PAN and CuCo ₂S ₄/PAN composites demonstrated an electromagnetic interference shielding efficiency of more than 90 and 97% at the entire x and ku-band frequencies, respectively.