The present invention relates to a polymer particles comprising a polymer bead stabilized by vinylsulfonyl-functionalized polymers grafted to the surface of the bead, as well as a particle composition comprising monodisperse polymer beads stabilized by vinylsulfonyl-functionalized polymers, wherein the vinylsulfonyl-functionalized polymers are grafted to the surfaces of the beads. The invention also includes a method of preparing monodisperse polymer particles comprising preparing a homogeneous solution of an ethylenically unsaturated polymerizable monomer, an initiator, and a polymeric stabilizer, wherein the polymeric stabilizer consists of repetitive units, wherein the repetitive units comprise latent vinylsulfonyl moiety, polymerizing the homogeneous solution, and converting the latent vinylsulfonyl moiety to vinylsulfonyl moieties.