Synthesis, characterization and magnetic properties of polyaniline-magnetite nanocomposites

In this work we report a new and straightforward method to prepare the polyaniline-magnetite nanocomposite PANI-Fe3O4. The method utilizes Fe3O4 nanoparticles as the oxidizing agent assisted by UV light to synthesize PANI-Fe3O4 magnetic nanocomposite. FTIR and XRD analyses confirm that polyaniline has been obtained in the emeraldine salt form and that the mean diameter of the Fe3O4 nanoparticles before synthesis was of the order of 25 nm; for the PANI-Fe3O4 nanocomposite in HCl after 4 h of reaction, the mean diameters were of the order of 11 nm. Also, feroxyhite was detected as a secondary phase for the nanocomposite. The dc conductivity results for the pure magnetite were about 2.4 × 10−6 S cm−1, while the nanocomposites were of the order of 10−5 S cm−1, confirming the increase in conductivity with the increasing amount of PANI. The magnetic measurements showed ferromagnetic behavior for the nanoparticles, with high-saturated magnetization (MS = 74.30 emu g−1) and a coercive force of 93.40 Oe. In addition, it was observed that the saturated magnetization for the nanocomposite strongly depends on the reaction time under UV irradiation.