Fabrication of functional microcapsules containing two-phase suspensions for microparticle-based displays

In this work, urea-formaldehyde microcapsules containing two-phase suspensions in which the pigment benzidine yellow 14 (BY-14) particles were homo-dispersed in a dielectric fluid for use in microparticle-based displays were prepared by in situ polymerization of monomers in an oil-in-water emulsion. Benzidine Yellow particles were modified by charge control agents in the mixture of tetrachloroethylene and sec-butylbenzene, and these particles can be prevented from coagulation using span 80 as the stabilizer in suspensions. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed to investigate on the microcapsule size and surface morphology. Experiments revealed that the pigment particles in the microcapsule possessed reversible response while providing an electric field.