Preparation Of Materials For Microcapsulated Electrophoretic Display And Eletrophoretic Display Prototype

With the advent of the information age,such as wide applications of personalcomputers,internet and other digital media platform,displays which are windows ofhuman-computer interaction have become a part of modem life.It is urgent need forpeople to have a comfortable reading,ultra-thin,low consumption of power flexiblepanel display.As a leading e-paper technology,microcapsulated electrophoreticdisplays (EPDs) will change the life style of human being.EPDs technology covers thechemical,physical,electrical,optical,informational,energy subject disciplines andcross-intersection of research,and has important scientific significance and applicationvalue.The paper first describes the preparation and characterization of TiO₂ particleencapsulated by styrene (st) and sodium vinylbenzensulfonate (NaSS) copolymer.Experimental result provided direct and clear evidence for the presence of P(St-NaSS)shell on TiO₂ particles.The density of core-shell composites is 3.05g/cm³.P(St-NaSS)/TiO₂ particles dispersed well in microcapsules with no conglomeration.ThePS/TiO₂ core-shell particles were prepared by in-situ sol-gel method and characterizedby means of FTIR spectroscopy,scanning electron microscopy (SEM),transmissionelectron microscopy (TEM),thermogravimetric analysis (TGA),and contact anglemeasurement,etc.The density of core-shell composites is 1.17g/cm³.Dispersionstability depends not only on the density matching between composite particles andsolvent,but also on the steric stabilization.Compatibility enhanced chains ofcomposites extend into the good solvent medium and interact positively with the bindermolecules and the solvent.Zeta potential and mobility of particles in non-aqueousmedium were measured by Brookhaven Zeta sizer,and results show that P(St-NaSS)/TiO₂ and TiO₂/PS have higher zata potential and mobility than TiO₂.The GE/NaCMC/SDS microcapsules,GE/NaCMC/SLS microcapsules andGE/NaCMC/SDBS micrcocapsules were prepared by complex coacervation.Experimental result shows that small molecule surfactant plays a key role in complexcoacervation.Stable,uniform,and surface-smooth GE/NaCMC/SDS andGE/NaCMC/SLS microcapsules were prepared by change the amount of smallmolecule surfactant.The microcapsules were characterized in terms of microstructure, morphologies,thermal stability,and release behavior by scanning electron microscopy(SEM),optical microscopy,and thermogravimetric analysis (TGA).It wasdemonstrated that the membranes of the microcapsules were formed from nano sizedcoacervate droplets.Microcapsules with elastic,nonpermeable,optical transparent etcwill enhance the performance of electrophoretic displays.Gelatin/alginateMicrocapsules were synthesized by complex coacervation.The average diameter ofmicrocapsules was controlled by the agitation rate and the narrowest size distributionwas prepared at 500rpm.Microcapsules were characterized by means of opticalmicroscopy,scanning electron microscopy (SEM),and thermogravimetric analysis(TGA) and results showed the microcapsules have smooth surface and transparent wallwhich have compact microstructure,In this experiment,GE/NaCMC/SDS microcapsules,GE/NaCMC/SLSmicrocapsules and GE/SA microcapsules were also prepared by complex coacervation,and the thickness of microcapsules was 0.9μm,0.2μm,2-3μm respectively.However,thermal stability of GE/NaCMC/SDS microcapsules were best and GE/SAmicrocapsules were worst which show that thermal stability determined by themiostructure of microcapsules and have no obvious relationship with microcapsulesthickness.Electrophoretic display prototype was prepared by coating a slurry containingelectrophoretic ink microcapsules on ITO glass with nearly single layer by regulateslurry's viscosity and blade speed.The marks of Zhejiang University with differentcoloos were displayed at low volt of 3v,and the contrast ratio was 2.83,2.27,and 2.41respectively.Electrocircuits with different Line width in the range of 100-1000μm weredisplayed clearly,and responsive time was less than 600ms.The clock display is theimportant application toward industrialization of EPDs.