Preparation of polyaniline coated poly(methyl methacrylate) microsphere by graft polymerization and its electrorheology

Monodisperse acrylic microspheres (diameter 9.2 μm) (An-PGMA) with aniline moieties on the surface were initially prepared by a seeded emulsion method, and then composite particles (PA-PGMA) possessing polyaniline (PANI) shell were prepared via an in situ polymerization of aniline using An-PGMA particles as a core material inducing grafting polymerization of aniline. The PANI layer was found to be formed on the An-PGMA surface from the microscopic image, 13C FT-NMR and TGA of the PA-PGMA particles. Suspension of the PA-PGMA particle dispersed in silicone oil showed typical electrorheological (ER) characteristics under external electric fields.