Post polymerization solvent effect on conducting polyaniline and electromagnetic interference shielding effectiveness in X-band regime

Intrinsically conducting polymers (ICPs) have moderate conductivity inducing losses and more attenuation. Among ICPs, polyaniline have high electrical conductivity, flexibility and constant shielding effectiveness (SE) over wide frequency range. The emeraldine salts are conducting due to partial oxidation of aniline and delocalised π- bonds. Its formation depends upon dopant, oxidant and solvent for washing. The current work is aimed at process induced modification in conducting polyaniline and its effect on electromagnetic interference shielding effectiveness in X-band frequency range. The synthesis has been accomplished by in-situ oxidative polymerization. To remove unreacted content from polymerized solutions, samples were washed with ethanol and IPA (isp-propyl alcohol) named as PE and PIP respectively. The value of conductivity is 0.03 S/cm and 0.19 S/cm for PE & PIP. Total SE achieved is ~43 dB and ~23 dB for PIP and PE, respectively. The processing of highly polar ethanol during washing, affects the π- interaction of aniline. IPA can stabilize charges present in aniline by increasing π- bond delocalization leads to better conjugation, more conductivity and shielding effectiveness. The skin depth of PIP is 0.9 µm and 1.3 µm for PE which incorporates with σ_AC (120 S/m) for PIP. PIP has better conductivity by contributing to absorption dominated shielding effectiveness making it more suitable in applications such as stealth technology, communication purposes, etc.