Magnetite-polypyrrole core-shell structured microspheres and their dual stimuli-response under electric and magnetic fields

Polypyrrole (PPy)-coated magnetite (Fe3O4) hybrid particles were synthesized under sonication. PPy was coated on the surface of Fe3O4 microspheres, whereas pyrrole monomers filled the interior of the Fe3O4 particles and were then polymerized. The s(t) ructure of the Fe3O4-PPy microspheres was confirmed by transmission electron microscopy. The electric and magnetic properties were confirmed by optical microscopy and vibrating sample magnetometry, respectively. The suspension of the Fe3O4-PPy composite microspheres dispersed in silicone oil exhibited both electrorheological and magnetorheological properties when measured using a rotational rheometer under an applied electric and magnetic field, respectively.