On the correlation between structural characterization and electromagnetic properties of doped polyaniline

Redoped-polyaniline (PANI) was prepared by chemical redox polymerization of aniline using ammonium perdisulfate, (NH4)2S2O8, as an oxidant and hydrochloric acid, HCl, as a doping agent. The structural characterization based on FT-IR, UV–vis, XRD, TEM and electrical conductivity was first used to evaluate the thermal stability and the electromagnetic properties. The redoped-PANI was partial crystalline nature and similar spherical structure about 4–5 nm in diameter. The redoped-PANI displayed outstanding electric conduction and thermally stability. The volume resistivity was as high as 5.18 × 10−1 Ω cm. Doped-PANI maintained stable conductibility at temperatures up to about 100 °C. The redoped-PANI had excellent dielectric properties, multiple Debye dipolar relaxation, and substantial microwave absorption capability. The values of ɛ′rɛ′r and ɛ″rɛ″r for the redoped-PANI powder were from 9.31 to 5.95 and 3.44 to 2.10, respectively. The maximum reflection loss of redoped-PANI composites of 2.0 mm thickness were −14.3 dB at 16.4 GHz and the effective absorption band under −10 dB was from 10.0 to 13 GHz.

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