Improved Electromagnetic Interference Shielding Response of Poly(aniline)-Coated Fabrics Containing Dielectric and Magnetic Nanoparticles

Abstract

Composite absorbers based on conducting fabrics possessing moderate conductivity and dielectric/magnetic properties were prepared by in situ incorporation of nanoparticles of BaTiO 3 (15−25 nm) or Fe 3 O 4 (25−40 nm) within coated poly(aniline) (PANI) matrix. The X-ray diffraction patterns and transmission electron microscopy images confirmed the formation of PANI coating and incorporation of BaTiO 3 or Fe 3 O 4 nanoparticles. Scanning electron microscopy images show formation of thick and uniform coating of PANI over individual fibers and in interweave regions. The dielectric studies show that incorporation of BaTiO 3 lead to enhancement of dielectric properties of PANI whereas magnetization measurements revealed that incorporation of Fe 3 O 4 resulted in noticeable improvement in magnetic properties with saturation magnetization of 17.9 emu/g. The Ku-band (12.4−18.0 GHz) shielding studies revealed that pure PANI-coated fabric show total shielding effectiveness (SE T ) of −15.3 dB which enhanced to −16.8 and −19.4 dB after incorporation of BaTiO 3 and Fe 3 O 4 nanoparticles respectively. Such an improvement can be attributed to the better matching of input impedance, reduction of skin depth, and additional dielectric/magnetic losses. The high value of absorption-dominated SE T (i.e., 97−99% attenuation) and specific shielding effectiveness value of 17−20 dB cm 3 /g demonstrate the potential of these fabrics as promising microwave-shielding material. In addition, these fabrics also display good antistatic response with static charge decay time of only 0.11 s.

Graphene-reinforced carbon composite foams with improved strength and EMI shielding from sucrose and graphene oxide

“…A drastic decrease in SSE with GO concentration from 1 to 1.25 wt% is due to the rapid increase in foam density due to foam collapse. The observed SSE of graphene-reinforced carbon composite foams is much higher than that of copper (10 dB g -1 cm -3 ) and the highest reported SSE of carbon foams (130 dB g -1 cm -3 ) [64,71,72]. Moreover, the predominance of the absorption contribution makes graphene-reinforced carbon foams useful in EMI shielding applications where stealth is more important [73].…”

Carbon nanostructure composite for electromagnetic interference shielding

“…For loading 1 : 1 wt% of PANI/TBT, maximum total shielding effectiveness of 71.5 dB was reported [22]. In another work they prepared conducting fabric with PANI incorporated with Fe 3 O 4 or BaTiO 3 with a maximum shielding of 16.8 and 19.4 dB respectively [23]. The high permittivity value due to the incorporation of BaTiO 3 in the PANI-coated fabric results in the enhancement of polarization.…”

Lightweight graphene nanoplatelet/boron carbide composite with high EMI shielding effectiveness

“…7,16,17 Carbon materials, especially flexible graphene films with micro-sized thickness, have also been demonstrated to exhibit exceptionally high EMI SE as well as in-plane thermal conductivity. [18][19][20] However, the major restrictions for the conducting polymer composites and flexible graphene are the inferior temperature stability and mechanical properties, respectively.…”