Magnetorheological Characteristics of Nano-Sized Iron Oxide Coated Polyaniline Composites

We synthesized magnetic smart composite particles comprising polyaniline (PANI) and Fe
₃
O
₄
nanoparticles (PANI@Fe
₃
O
₄
) by a micelle-assisted self-assembly method and evaluated their magnetorheological (MR) properties. The microstructures of the PANI@Fe
₃
O
₄
composites were characterized by using scanning electron microscopy and X-ray diffraction analysis. The chemical structure of the composites was also investigated using Fourier transform-infrared spectroscopy, while their magnetic properties were characterized using a vibrating sample magnetometer. The MR properties of the PANI@Fe
₃
O
₄
-based MR fluid were examined using a rotational rheometer with a magnetic field supply device. Typical MR characteristics, such as shear viscosity, shear stress, dynamic yield stress, and dynamic moduli, were obtained from the rheological measurements, and they increased with applied magnetic field strength.