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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.

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Organic conductive polymers are at the forefront of materials science research because of their diverse applications built around their interesting and unique properties. This work reports for the first time a correlation between the structural, electrical, and electromagnetic properties of polyaniline (PANI)-tetragonal BaTiO3 (TBT) nanocomposites prepared by in-situ emulsion polymerization. XRD studies and HRTEM micrographs of these nanocomposites clearly revealed the incorporation of TBT nanoparticles in the conducting PANI matrix. EPR and XPS measurements reveal that increase in loading level of BaTiO3 results in a reduction of the doping level of PANI. The Ku-Band (12.4-18 GHz) network analysis of these composites shows exceptional microwave shielding response with absorption dominated total shielding effectiveness (SET) value of -71.5 dB (blockage of more than 99.99999% of incident radiation) which is the highest value reported in the literature. Such a high attenuation level, which critically depends on the fraction of BaTiO3 is attributed to optimized dielectric and electrical attributes. This demonstrates the possibility of using these materials in stealth technology and for making futuristic radar absorbing materials (RAMs).

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