Electropolymerization Of Polyaniline And Preparation And Characterizations Of Magnetic PANI/Fe₃O₄ Nanocomposites

Conducting polyaniline has special electrical and magnetic properties.It is one of the most intensively investigated conductive polymers due to its environmental stability,low cost of raw material and ease of synthesis.In this thesis,PANI films had been obtained by electropolymerization.Polyaniline including Fe₃O₄ nanoparticles,which were doped by dodecylbenzene sulfonic acid(DBSA),were synthesized via an in-sit polymerization.(1)Polyaniline films with different colors were deposited on the ITO glass electrode in sulphate acid solution containing aniline by means of electropolymerization.FT-IR analysis shows that the doped process occured at the N atom of the quinonoid rings.With the reaction continueing,the structure of the doped PANI transits from nanoparticles to nanofibers.Finally,nanofibers got together. Colors of the PANI were also discussed.(2)Fe₃O₄ nanoparticles were synthesized in air.DBSA-PANI/Fe₃O₄ nanocomposites were synthesized via an in-situ polymerization of aniline monomer in DBSA aqueous solutions which contained Fe₃O₄ nanoparticles prepared previously. DBSA serves as surfactant and dopant.The nanocomposites were characterized by means of XRD,TEM,SEM,FT-IR.The results show that the Fe₃O₄ nanoparticles disperse in the DBSA-PANI and the structure of the DBSA-PANI/Fe₃O₄ nanocomposites looks like peanuts embedded in the cake.The Fe₃O₄ nanoparticles are between 10 and 20 nm in size.With increasing content of the Fe₃O₄ nanoparticles,the saturation magnetization(M_s)of the nanocomposites increases from 1.33 emu/g to 19.72 emu/g and the coercivity(H_c)is in the range of 72-82 Oe.The conductivity of the nanocomposites decreases gradually from 4.05×10^-4S/cm to 1.35×10^-4S/cm with increasing content of the Fe₃O₄ nanoparticles.