Multifunctional Fe₃O₄ nanoparticles-embedded poly(styrene)/poly(thiophene) core/shell composite particles

Fe₃O₄ nanoparticle-embedded poly(styrene)/ poly(thiophene) core/shell composite particles (Fe₃O₄ NPs-PSt/PTh) with multi-functionality (i.e., magnetic, electrical conducting properties, and photoluminescence) were successfully fabricated via stepwise polymerizations. First, Fe₃O₄ NPs-PSt composite particles were prepared in a miniemulsion polymerization. Then, the Fe₃O ₄ NPs-PSt/PTh core/shell composite particles were prepared by oxidative seeded emulsion polymerization of thiophene in the presence of FeCl₃/H₂O₂ as a redox catalyst. The composite particles were characterized by Fourier transform-infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectroscopy to confirm the composite structure. Transmission electron microscopy (TEM) analysis confirmed the core/shell morphology of the Fe₃O₄ NPs-PSt/PTh. Photoluminescence (PL) spectroscopy and superconducting quantum interference device (SQUID) magnetometer analyses confirmed that the composite particles exhibited fluorescence and superparamagnetic properties, respectively. Electrical conductivity of the composite particles was measured by a 4-point probe method and the results revealed that the electrical conductivity of embedded Fe ₃O₄ NPs increased 10 folds greater than that of the pristine PSt/PTh core/shell particles.