Seeded swelling polymerized sea urchin-like core-shell typed polystyrene/polyaniline particles and their electric stimuli-response

Core-shell structured sea urchin-like polystyrene/polyaniline (PS/PANI) particles were synthesized by a seeded swelling polymerization process, in which an aniline monomer was initially absorbed into the PS particles due to pi-pi* stacking interactions and an initiation step of the polymerization of aniline was carried out by ferric ions added. The morphology of the product particles was observed by scanning electron microscopy and transmission electron microscopy images. Their chemical bonding was examined via Fourier transform- infrared spectroscopy, while their thermal stability was studied by thermogravimetric analysis. The fabricated PS/PANI particles were dispersed in silicone oil to produce an electrorheological (ER) fluid, and then their ER characteristics were observed using both optical microscopy and a rotational rheometer to study rheological properties including shear viscosity, shear stress and dynamic yield stress in an electric field, exhibiting typical ER characteristics. Dielectric spectra were further analyzed by using a LCR meter.