Conductive polymers are widely studied as microwave absorbing materials due to their light weight, corrosion resistance, good and flexible processibility and variability of conductivity. Among them, polyaniline (PANI) microwave absorbing materials have been studied most extensively because of their easier and inexpensive preparation methods, good environmental stability in both doped and undoped forms, excellent physical and chemical properties, high conductivity at microwave frequencies and unique doping mechanism with its ease of protonic acid doping in the emeraldine form. In this paper, the preparation and the microwave properties of PANI/inorganics composites and PANI/insulating polymer composites are thoroughly reported.

With itaconic acid as dopant and (NH₄)₂S₂O₈ as oxidant, itaconic acid–doped polyaniline (PANI) nanorods were prepared by one-step and template-free polymerization method. The influence of the polymerization parameters such as the oxidant–aniline molar ratio, the oxidant concentration, the molar ratio of itaconic acid and aniline, and the itaconic acid concentration on the yield and conductivity of PANI was investigated by single factor analysis method. The yield and conductivity of itaconic acid–doped PANI were 112.5% and 2.06 × 10⁻³ S cm⁻¹, respectively, when synthesized under the optimal reaction condition at room temperature. From the Fourier transform infrared and ultraviolet visible spectra, it can be demonstrated that PANI was successfully doped by itaconic acid and the conductivity was maximum when the ratio of benzene ring and quinine ring was 3:1 and the doping ratio of quinine ring reached 50%. Microstructure images showed that PANI has nanosized rod-like morphology.