Preparation Of Yellow Polymeric Dyed Nanopaticles And Their Applications On Electrophoretic Display

Electrophoretic display as one of the electronic paper technologies is fully reflective type display devices, which utilizes electrophoretic phenomena of charged pigment particles dispersed in a colored solvent. Microencapsulated electronic ink concerns numerous microcapsules which are applied to encapsulated electrophoretic medium containing electrophoretic particles, suspension medium, charge control agent and stabilizer. This dissertation mainly covers the preparation of yellow polymeric dyed nanoparticles, charge control agent and a series of microcapsules and they are applied in electrophoretic display(EPD) with superior performance. Yellow polymeric dyed nanoparticles were prepared by dispersionpolymerization of styrene and N-(9,10-dioxo-9,10-dihydro-anthracen-1-yl)-acrylamid in methanol/water/pyridine with divinylbenzene(DVB) as crosslinker,polyvinyl- pyrrolidone(PVP) as stabilizer, and 2,2'-azobis(2-methylpropionitrile)(AIBN) as initiator. The influences of reaction medium, the amount of DVB,PVP and AIBN on the preparation of the nanoparticles were studied through orthogonal experiments. It was found that the amount of PVP was the chief factor which affected particles diameter. Under the prime condition, the particle size of the polymeric nanoparticles was about 300nm,the density was 1.14g/cm3 and the mono-dispersity was good.Charge control agent o-benzoic acid sulfimide was synthesized with o-toluenesulfonamide as raw material and KMnO4 as oxidant. The influences of pH, reaction time, addition method of KMnO4 and reaction temperature on the reaction yield were investigated.Electrophoretic particles were prepared by milling, with yellow polymeric dyed nanoparticles as particles, Span 80 as stabilizer, and T151 or T152 as charge control agent. It was found that dispersibility of this kind of particles was 83.2% and electrophoretic mobility was -0.02635cm2V-1s-1 in tetrachloroethylene(TCE)- dodecyl benzene(DDB) as suspension medium; dispersibility of this kind of particles was 85.3% and electrophoretic mobility was -0.05624cm2V-1s-1 in TCE-Isopar H as suspension medium.Microcapsules were prepared through complex coacervation method, with gelatin-gum Arabic as wall material. It was found that gelatin-gum Arabic microcapsules had smooth surface, superior transparence and high encapsulation efficiency. Yellow polymeric dyed nanoparticles were applied in EPD via above preparation methods. And it was found that electrophoresis was reversible and response time was about 7.5s under the condition of 20V/mm.