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

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.