Magnetic composites of conducting polyanilineano-sized magnetite and their magnetorheology

摘要

Magnetorheological (MR) fluids, composed of colloidal particles dispersed in a carrier liquid, possess controllable rheological properties by an external magnetic field, showing dramatic changes of yield stress and shear viscosity caused by transformation between solid-like to liquid-like state. As a new MR material, we synthesized conducting polyaniline (PANI)ano-sized Fe_3O_4 composites which could be adopted as a dispersed phase of MR fluids. Composites containing nano-sized Fe_3O_4 were synthesized via a chemical reaction method. Microstructure of the PANI/Fe_3O_4 composites was characterized by SEM and XRD. Magnetic property of the composites was characterized by VSM. Furthermore, MR fluid based on PANI/Fe_3O_4 composites was investigated using a rotational rheometer equipped with a magnetic field generator, exhibiting a typical MR performance of which shear stress of the fluids increased abruptly under magnetic fields.