Electronic Ink Material Preparation

The electronic paper and electrophoretic ink are a couple of twisted conceptions which have been usually being confused . Indeely, both are so comprehensive that almost every flexible .double stable display material can be called E-ink generally.This treatise's object is to provide encapsulated electrophoretic display material, a subset of E-ink. This kind of material contains light particles taking on front colour and dark suspension medium taking on background colour in microcapsules. Particles can arrive at front bottom of microcapsule making there the colour of particles under electrical field ,and back to rear bottom of capsules in order to the front bottom regain the colour of suspension medium by applied another eletrical field. Numerous those microcapsules arraied on soft substrate can play image.The structure of this kind of E-ink can be summurized as numerous microcapsules containing electrophoretic display fluids .which comprising particles, suspension medium, charge control agent and dispersion aiding agent. The main achievements of this treatise are described below:1.Titania particles have been produced by sol-gel technology to provide a electrophoretic particles , and the surface of particles have been modified by coating PMMA.PVA or by adsorping steric acid on the surface of paticles. The suspension medium mainly comprises tetrachloroethylene mixed with methylbenzene, dimethylbenzene and cyclohexane. The properties such as viscocity, dielectric of a series of suspension medium differed in weight ratio of each component has been reserached. Take sodium dodecylbenzene sulfonate, ammonium cetyl trimethyl bromide, SPAN-80 as charge control agent .2 E-ink microcapsules with a urea-formaldehyde resin tegument have been manufactured by in-situ plomerization . An improved in-situ plomerization of encapsulating the electrophoretic fluids with UF resin has been developed. This method can be described as using low moleculer weight UF resin, which iswater soluble, instead hydroxy methyl urea and dihydroxymethyl urea as monomer of polmerization.This way take merits of high productivty and smooth surface morpholog.The crux of of the process is to acquire appropriate low moleculer weight aqueous UF resin .For this reason ,the infulence of reaction conditions such as temprature.time, pH value.the mol-ratio of urea and formaldehyde, etc on viscosity and surface tension of aqueous solution of resin has been investigated. And the productivity influenced by reaction conditions and the surface activity has also been investigated.3.A novel way to produce E-ink material based on UF resin matrix has been developed, which can be characterized as dispersing electrophoretic fluids in dense aqueous of low moleculer weight UF resin to get O/W emulsion by stirring, then heating to induce polmerization and when reaction finished .electrophoretic fluids has been buried in the cavities of transperant UF resin. This means is superior to encapsultion in the simplicity of manufacturing process. The crux of acquiring qualified product in this process ,the viscosity of resin .which influenced by reaction conditions such as temperature.time, pH value.the mol-ratio of urea and formaldehyde, has been researched. The product is transperant and burlly and its response to electircfield has been investigated by using two flat electrodes attached to the surface of product .which generate an electric field with a strenghth of about 125V/mm,while product respond to this electric field within 0.5s.