Modeling and analysis of nematic liquid crystals in thin geometries: Bistable configurations and free surface instabilities

薄几何形状向列液晶的建模和分析：双稳态配置和自由表面不稳定性

• 批准号: 0908158
• 负责人: Linda Cummings
• 金额: $ 39.93万
• 依托单位: New Jersey Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908158&HistoricalAwards=false
• 关键词: Modeling; analysis; nematic; liquid; crystals

CummingsDMS-0908158 This project centers on developing new analytical models fornematic liquid crystals (NLCs) in two basic configurations. Thefirst concerns NLCs "sandwiched" between two solid boundaries,subject to an applied electric field. This geometry is directlyrelevant to a number of liquid crystal display devices. Byinvestigating the response of the NLC layer to an externalelectric field, the investigator and her colleage develop newmodels relevant to the design of bistable LCD devices. Advanceshere could lead to the development of new, easily-manufactured,energy-saving technologies. The second configuration considersfree-surface dynamics of NLC films and drops, relevant tonumerous manufacturing processes. Mathematically, the problem iscomplicated by the need to model carefully the liquid crystalbehavior in the vicinity of any contact lines. This, in additionto the known unstable behavior, leads to a very complex problem,about which little is known theoretically. Systematic asymptoticreduction of the complex Ericksen-Leslie equations for nematicmedia, to the appropriate thin-film geometry, is made. Theformulation includes the effects of finite anchoring strength ofthe liquid crystal director field at the boundaries, and theeffects of liquid-solid interaction energy (via a disjoiningpressure). The theoretical investigations are augmented by anexperimental program, comprising simple table-top experimentscarried out by summer students at NJIT, and more sophisticatedinvestigations carried out by an experimental collaborator, PeterPalffy-Muhoray, at Kent State University. The project has two strands: A theoretical investigationinto optimal design of low-energy (so-called "bistable") LiquidCrystal Display (LCD) devices, for use in applications such ase-paper; and an investigation into the dynamics of nematic liquidcrystals spreading on surfaces, a process known to be unstable incertain situations. The development of a theoretical base for aworkable, easily-manufactured, low-energy LCD device would haveundeniable economic and environmental impact if it provedcompetitive, in terms of cost or performance, with the smallnumber of such low-energy LCD microtechnologies presentlyavailable. The investigations into free-surface spreading leadto a better understanding of coating processes and, particularlywith the inclusion of an electric field, offer potential for newways of controlling the evolution of spreading films inmanufacturing processes. This project is carried out incoordination with educational efforts that include invaluableresearch experiences for undergraduate students.

CummingsDMS-0908158该项目以两种基本配置开发新的分析模型（NLC）。 首先涉及在两个固体边界之间“夹紧”的NLC，但要受到施加的电场。 这种几何形状直接偏向许多液晶显示器。 通过对NLC层对外部电场的响应进行评估，研究者及其愿意与Bistable LCD设备的设计相关。 Advanceshere可能导致开发新的，易于制造的节能技术。 第二种配置考虑了NLC薄膜和滴剂，相关的调整制造工艺的曲面动力学。 从数学上讲，问题是由于需要在任何接触线附近仔细建模液晶行为的需要。 除了已知的不稳定行为外，这还导致了一个非常复杂的问题，从理论上讲，这几乎没有知道。 对nematicmedia的复杂埃里克森 - 莱斯方程进行系统的渐近redression，以适合适当的薄膜几何形状。 该形成包括边界处液晶主场场的有限锚固强度以及液体固相互作用能量的影响（通过脱节压）。 理论上的研究是通过账户计划进行的，其中包括由NJIT的夏季学生进行的简单桌面实验，以及由肯特州立大学的实验合作者Peterpalffy-Muhoray进行的。 该项目有两条链：理论研究ininto ininto低能（所谓的“ Bissable”）液体晶体显示器（LCD）设备，用于ASE-PAPER；并研究了在表面上散布的列晶体的动力学，这一过程已知是不稳定的不确定情况。 如果在成本或绩效方面证明具有竞争力的竞争力，那么建立可敬畏，易于制造，低能的LCD设备的理论基础将对经济和环境产生影响，而这种低能的LCD LCD微技术目前可利用。 对自由表面扩散的调查，以更好地了解涂层过程，尤其是在包括电场的涂层过程中，为控制传播薄膜制造过程的演变提供了潜力。 该项目与教育努力无关，其中包括针对本科生的无效研究经验。