High performance X-band electromagnetic shields based on methyl-orange assisted polyaniline-silver core-shell nanocomposites

Present communication explores the remarkably high shielding effectiveness of about 70 dB, exhibited by advanced core-shell-type polyaniline-silver nanosheets (PAg) in X-band (4-12 GHz), synthesized from methyl-orange assisted chemical oxidative polymerization route. The high-resolution tunneling microscope reveals the formation of PAg nanogranules and nanosheets with different silver nitrate concentrations (0.3 M and 0.6 M, respectively). The enhanced shielding effectiveness of nanosheets compared to other samples is attributed quite sensitively to its high conducting value, which is predominantly determined by the concentration of silver nitrate used during synthesis. The structural characterizations using high-resolution X-ray diffraction technique reveals the enhanced crystallinity of PAg samples, which significantly contributes to the enhancement of their conductivities. The dc charge transport study in temperature range 77 K-300 K reveals that the PAg samples exhibit metallic behavior, whereas the polyaniline samples show semi-conducting nature. This can be ascribed to the presence of silver content in nanocomposites, which results in higher conductivities of the PAg samples. This study opens a new window for shielding of electromagnetic pollution by advanced core-shell morphologies at commercial scale.