Template-free synthesis of hollow poly(o-anisidine) microspheres and their electrorheological characteristics

Hollow poly(o-anisidine) (POA) microspheres were synthesized by chemical oxidation polymerization using a template-free method. The structure and morphology were characterized by SEM, TEM and FT-IR. The results indicate that the diameter of the hollow spheres is around 1 mu m and hollow POA shows a similar chemical structure to the granular form. The rheological properties of suspensions of hollow POA microspheres and granular POA particles were investigated under both steady and oscillatory shear with the application of electric fields. It was found that a suspension of hollow POA microspheres showed typical electrorheological (ER) behavior under an applied electric field, but exhibited lower ER activity than a granular POA suspension despite its higher stability. The lower ER performance of the POA suspension could be attributed to its weaker interfacial polarization as revealed by dielectric analysis.