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

Abstract

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 structure 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.