Study On The Principle Of Electrophoresis E-ink Of Dye

Electronic paper technology has received a great deal of attention in recent years. Electronic paper is a paper—like display monitor which has many properties such as high reflection, wide visual angle, portability, flexibility and bistable. Electrophoresis image displays (EPID) is the most likely candidate in search for a display which has these properties.Traditional EPIDs are thin, flexible reflective displays based on the movement of electrical charged pigment particles which are dispersed in a colored dielectric medium. Most of the reported prototype electronic papers are based on the electrophoresis of charged particles in colloidal suspension, which take the inorganic pigment titanium dioxide (TiO2) or silicon dioxide (SiO2) as particles. The dielectric medium such as tetrachloroethylene, isopar, xylene, are of high specific gravity to compatible with pigment particles. However, the pigment electrophoresis ink has a problem with suspension stability such as agglomeration, lateral migration and sedimentation because of the high density of pigment. Other materials which can substitute pigments as colored particles and the solvents which can disperse the colored particles well will be introduced later in this paper. Indeed, there are many papers referring to organic and inorganic pigment particle electrophoresis colloid, while less report is concerned about the electrophoresis of dye. In order to prepare a novel electronic ink, this study has been focused on the principle of electrophoresis of dye in different solvent or surfactant, and the relationship between the composition and electrophoresis properties of the electronic ink of dye.Dozens of dye have been tested in this paper including dispersed dyes, acid dyes, solvent dyes, metal complex dye and etc. To compatible with dye, several kinds of solvents and charge control agents also have been tested including pyridine, ethanol, xylene, Tetrachlorethylene, diethylamine, aniline, PIBI. Dyes were dissolved or dispersed in the solvents with certain surfactant and the electrophoresis performance of the solvent was observed in electrophoresis display prototype which was composed by 2 pieces of parallel ITO glass.The process of dye electrophoresis was described by photos of Metallurgical Microscopy; the density change of dye system before and after electrophoresis was recorded by X-Rite, in these ways we generally know the phenomenon of dye electrophoresis.The electrochemistry reaction of the dye, solvent and electrode was determined by electrochemistry station. It can be found that the system consisting of conductive medium is instable in electrophoresis. Electrode, electrophoresis media and dyes would be suffered electrochemical damage under the supplied voltage. Most of the dye in polarity medium would decompose during electrophoresis if the applied voltage is higher than certain value.And we also study the state of dye in the solvent. It was confirmed that the dye was not existed individually in the solvent, but was gathered together. Because dye particles of electronic ink was smaller than pigment of Electronic ink, so it was solved that pigment in the solvent were easily gathered. And luckily it was showed that it was clear and easily distinguishable before and after the dye system electrophoresis.Additionally, we tested the dye electrophoresis response time through UV-Vis spectrophotometer, and studied the factors of influencing dye electrophoresis response time, including the voltage, the concentration of dye system and structure of dye. And the UV-visible absorption change of a fixed point with time was also systematically studied.It was insufficient that the best electrophoresis performance is the dye solution of weak polar system in the present, when the voltage greater than a certain value, the system will happen electrochemical reaction, leading to dye decomposition.