【作者】 李炜罡；

【导师】 汪茫； 陈红征；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2009， 博士

【摘要】 随着信息时代到来，诸如个人电脑和互联网等数字媒体平台的广泛应用，使得作为人机信息交流窗口的显示器已经成为现代生活的一部分。人们迫切需要一种阅读舒适、超薄轻便、超低能耗并能无线上网的平板柔性显示器。微胶囊型电泳显示器，作为领先的电子纸技术，将有可能改变人类生活的方式。微胶囊型电泳显示技术涵盖化学、物理、电学、光学、信息、能源等多个学科和研究领域交叉，涉及到多个行业，具有重要的科学意义和应用价值。用分散聚合法制备核壳结构的P （St-NaSS）／TiO₂复合粒子，利用IR、TGA、接触角、TEM等方法考察了实验条件对包覆在粒子上的聚合物含量的影响。实验表明包覆后的P（St-NaSS）／TiO₂电泳粒子在微胶囊中呈单个粒子状态分散良好，复合粒子的平均密度为3．05g／cm³。用原位溶胶-凝胶法制备核壳结构的TiO₂／PS电泳粒子，并利用SEM、TGA、TEM等方法考察了实验条件对TiO₂／PS复合粒子的表面形貌和性能的影响，复合粒子的平均密度为1．17g／cm3。在非水溶剂中，粒子的分散稳定性依赖于溶剂的密度和溶度参数的匹配。对于同一粒子，当溶剂之间的密度相差较大时，密度起主要作用。当溶剂之间的密度差异较小时，溶度参数起主要作用。通过测试P（St-NaSS）／TiO₂、TiO₂、TiO₂/PS电泳粒子在非水体系中的Zeta电位证明电泳粒子在绝缘悬浮液中存在电荷，P（St-NaSS）／TiO₂和TiO₂／PS均表现出比TiO₂更高的Zeta电位和泳动速度。用复凝聚法制备了明胶／羧甲基纤维素钠／十二烷基硫酸钠、明胶／羧甲基纤维素钠／十二烷基磺酸钠和明胶／羧甲基纤维素钠／十二烷基苯磺酸钠微胶囊。实验结果表明小分子表面活性剂在复凝聚过程中起着关键性作用。通过调节小分子表面活性剂的用量，制备出了光学透明的、表面光滑的、具有致密囊壁结构的明胶／羧甲基纤维素钠／十二烷基硫酸钠微胶囊和明胶／羧甲基纤维素钠／十二烷基磺酸钠微胶囊。通过扫描电镜方法表征发现，微胶囊壁是由纳米尺寸的复凝聚颗粒构成，结构致密。通过热失重、热缓释方法表征，证明微胶囊具有良好的密封性，这些特征都是电泳显示用微胶囊所必需的。用复凝聚法制备了明胶／海藻酸钠微胶囊，通过光学显微、扫描电镜、热分析、粒径分析等方法探讨了实验参数对微胶囊的影响。实验表明，微胶囊的平均粒径随搅拌速度的增大而变小，且当搅拌速度为500r．p．m时微胶囊的粒径分布最窄。明胶／海藻酸钠微胶囊表面光滑、囊壁光学透明而且结构致密。随着pH值的降低，囊壁继续增厚。在本实验条件下，用复凝聚法制得的明胶／羧甲基纤维素钠／十二烷基硫酸钠、明胶／羧甲基纤维素钠／十二烷基磺酸钠和明胶／海藻酸钠三种微胶囊，其囊壁厚度分别约为0．9μm、0．2μm、2-3μm，但其热稳定性却是明胶／羧甲基纤维素钠／十二烷基硫酸钠最好，明胶／海藻酸钠最差。这表明微胶囊的热稳定性首先与囊壁结构的致密程度有关，而与囊壁厚度关系不明显。运用刮刀式涂布方法，调节微胶囊涂布液的粘度和刮刀速度，使微胶囊接近单层排列在电极上，降低了电极间的距离，使显示获得较小的驱动电压。制作了单回路的原型器件，在较低的直流电压（3V）驱动下能够实现清晰的文字显示。电子墨水中含不同染料所制成器件的对比度分别为2．83，2．27，2．41。制作了多回路的原型器件，线宽为100-1000μm都能清晰显示，响应时间小于600ms。时钟显示器件的成功制备是微胶囊型电泳显示器的产业化的重要一步。更多还原

【Abstract】 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.更多还原