Fabrication of compact poly(methyl methacrylate-co-butyl methacrylate-co-acrylic acid) microcapsules for electrophoretic displays by using emulsion droplets as templates

Microcapsules with smooth, transparent, and compact walls used for electrophoretic displays (EPDs) were prepared and characterized. The approach to fabricate EPD microcapsules was based on templating an oil-in-water emulsion stabilized by monodispersed poly(methyl methacrylate-co-butyl methacrylate-co-acrylic acid) latex particles synthesized by dispersion polymerization. The individual latex particles were then transformed into robust capsule walls by successively using solvent swelling, covalent cross-linking, and sintering. The diameter of the emulsion droplets was controlled by changing the concentration of latex in the emulsion, and the thickness of the wall changed according to the diameter of the latex particles. These microcapsules for EPDs were applied successfully in preparing a clock display panel controlled by a single-chip microprocessor operated at a low direct current voltage, demonstrating that these microcapsules can be used in EPDs.