Hierarchical Carbon Nanotube-Coated Carbon Fiber: Ultra Lightweight, Thin, and Highly Efficient Microwave Absorber

Abstract

Strong EM wave absorption and lightweight are the foremost important factors that drive the real-world applications of the modern microwave absorbers. This work mainly deals with the design of highly efficient microwave absorbers, where a hierarchical carbon nanotube (CNT) forest is first grown on the carbon fiber (CF) through the catalytic chemical vapor deposition method. The hierarchical carbon nanotube grown on the carbon fiber (CNTCF) is then embedded in the epoxy matrix to synthesize lightweight nanocomposites for their use as efficient microwave absorbers. The morphological study shows that carbon nanotubes (CNTs) self-assemble to form a trapping center on the carbon fiber. The electromagnetic characteristics of resultant nanocomposites are investigated exclusively in the X-band (8.2-12.4 GHz) using the network analyzer. The synthesized nanocomposites, containing 0.35 and 0.50 wt % CNTCFs, exhibit excellent microwave absorption properties, which could be attributed to the better impedance matching conditions and high dielectric losses. The reflection loss (RL) of -42.0 dB (99.99% absorption) with -10 dB (90% absorption) and -20 dB (99% absorption) bandwidths of 2.7 and 1.16 GHz, respectively, is achieved for 0.35 wt % CNTCF loading at 2.5 mm thickness. The composite with 0.50 wt % CNTCF loading illustrates substantial absorption efficiency with the RL reaching -24.5 dB (99.65% absorption) at 9.8 GHz and -10 dB bandwidth comprising 84.5% of the entire X band. The excellent microwave properties obtained here are primarily due to the electric dipole polarization, interfacial polarization, and unique trapping center. These trapping centers basically induce multiple reflections and scatterings, which attenuate more microwave energy. This investigation opens a new approach for the development of extremely lightweight, small-thickness, and highly efficient microwave absorbers for X-band applications.

Retracted Article: A versatile strategy for alternately arranging the foam ratio layers of multilayer graphene/thermoplastic polyurethane composite foams towards lightweight and broadband electromagnetic wave absorption

“…Polymeric composites, owing to their exibilities for structure design and property modulation, light weight, and good processability, have been widely used in the design and implementation of EWAMs. [4][5][6] Dielectric absorbents, such as carbon nanotubes (CNTs), [7][8][9] carbon bers (CFs), 10,11 and graphene and its derivatives, [12][13][14] due to their light weight, high conductivity, high aspect ratio, good resistance against corrosion, and excellent mechanical properties [15][16][17][18] have been added into polymer matrixes to achieve EW-absorbing properties. The most important features of these absorbents are their strong absorption capacity (reection loss, RL) and broad effective absorption bandwidth (EB, RL < À10 dB, for 90% energy absorption).…”

Performance enhanced electromagnetic wave absorber from controllable modification of natural plant fiber

“…Here, 3 s is the static dielectric constant and 3 N corresponds the dielectric constant at innite frequency. 58 According to the equation, Cole-Cole plots should be shown as a semicircle, and a Cole-Cole semicircle represents a Debye relaxation process. 59 In Fig.…”

Porous carbon materials for microwave absorption

“…), carbon-based materials exhibit lower densities and stronger EM wave absorption abilities. [12][13][14][15][16][17][18][19][20] For example, there have been lots of studies on graphene and carbon nanotubes (CNTs) applied in MA fields due to their strong electrical conductivities, low percolation thresholds, and organized nanostructures. 6,11,14, However, the costeffective and large-scale production of graphene and CNTs remains a crucial challenge for commercial application, which seriously hinders their applications.…”