Preparation and application of core–shell Fe₃O₄/polythiophene nanoparticles

The Fe₃O₄/polythiophene nanoparticles, possessing core–shell structure, were prepared by two-step method. In the first step, the Fe₃O₄ particles were synthesized via co-precipitation of FeCl₃ and FeSO₄, using the NH₃·H₂O and N₂H₄·H₂O as precipitant system. In the second step, the thiophene adsorbed and polymerized on the surface of the Fe₃O₄ in the solvent of chloroform. Raman, FTIR, EDS, XRD, TEM, Zeta potential measurement and TG-SDTA were employed to characterize the composition and structure of the products. The results showed that the Fe₃O₄/polythiophene nanoparticles were successfully synthesized with good dispersion and stable core–shell structure, provided with average particle size of approximately 20 nm, in which the diameter of Fe₃O₄ core was approximately 14 nm and the thickness of polythiophene shell was approximately 3–4 nm. Then, the nanoparticles were added into alkyd varnish to prepare a composite coating. The neutral salt spray test, paraffin control test and mechanical test were carried out to identify the properties of the composite coating. It was found that the composite coating had good performances of anticorrosion and paraffin controlling when the mass fraction of the nanoparticles was 0.8–1 wt% in alkyd varnish. As a multifunctional material, the Fe₃O₄/polythiophene nanoparticles can be used in the internal coating of pipeline and have great potential application in crude oil pipeline transportation.