Trifluorotoluene As Suspension Medium For Colorful Electrophoretic Display

The dual colored microcapsule type electrophoretic display(EPD) used trifluorotoluene as liquid suspending fluid was prepared and studied in this paper. The formulations of red, yellow, blue, white with positive electricity and white with negative electricity electrophoretic fluid were investigated. The preparation of urea-formaldehyde microcapsules via in situ polymerization and the coating process using the method of screen printing were studied. The dual colored EPD divice showed high contrast image under low driving voltage.The formulations of trifluorotoluene electrophoretic fluid were investigated by orthogonal experiment and condition method.The best ratio of red/white, yellow/white and blue/white electrophoretic fluid in dual-colored electrophoretic fluid were studied and the simply electrophoretic display devices were prepared. The contrast ratio of these devices reached 2.95, 1.41 and 3.93, respectively, and the response time were 305ms/348 ms, 140ms/371 ms and 512ms/415 ms, respectively. All of the devices can keep steady in 30 minutes after outage.Functional microcapsules were prepared via in situ polymerization with urea –formaldehyde as wall materials, and the dual-colored trifluorotoluene fluid as core materials. The factors affecting the appearance and shape of microcapsules, such as mass of wall materials core materials, the concentration of gelatin solution, SDS solution and resorcinol solution, the stirring rate and the pH value, were discussed in this paper. The microcapsules showed sphericity, smooth surface and suitable sizes.The encapsulation efficiency reached 15.56% and efficiency reached 97.4%.The microcapsules could successfully response in 15 V driving voltage.The coating process using the method of screen printing was studied with trifluorotoluene microcapsules as coating materials.The influence of curing agent, the count of mesh and coating layer on the performance of coating was discussed in this paper.Microcapsule type EPD prototypes showed good display result without coating defect.The contrast of red/white microcapsule type EPD device was 1.81 in 15 V driving voltage.