Tailoring surface structure of polymer nanospheres in Pickering emulsion polymerization

Abstract

A series of surface-functionalized polystyrene (PS) nanospheres with similar particles size of about 100nm and adjusted content of sulfonate groups on the surface are prepared by Pickering emulsion polymerization using titania nanoparticles modified with a mixture of two surfactants as stabilizers. TEM and FE-SEM images indicate that the titania nanoparticles are firmly adsorbed on the surface of polymer nanospheres because of the electric attraction between negative charged surfactant molecules and positive charged titania particles. XPS and electrophoresis measurements confirm that the surfactant with a double bond has been successfully grafted on the surface of PS nanospheres, and the surfactant without a double bond is removed with titania nanoparticles. Polymer nanospheres with appropriate concentration of sulfonate groups on the surface have good colloidal stability in the nonpolar solvent and may be suitable for bistable electrophoretic display application.