RUI: New oxadiazole containing liquid crystals: Effects of structural changes on the biaxial nematic phase

技术总结这个由材料研究部固态和材料化学项目授予普吉特湾大学的瑞奖将使我们能够深入分析一系列恶二唑和含恶唑的液晶(LC)的结构变化如何影响双向向列相(Nb)的形成和稳定性。2004年在恶二唑衍生物中发现的这种独特的LC相，可能允许在LC显示器中进行更快的电光开关。然而，原始化合物在不切实际的高温下显示了Nb相。获奖者Eric Scharrer和他的本科生在初步工作中证明，在含有恶二唑的衍生物中加入侧甲基是降低向列相起始温度的一种成功方法。这项研究将包括系统地改变不同侧基(烷基和卤素)的位置，以探索空间和电子因素对双向向列相的影响。目标化合物的合成(由本科生和一名社区大学讲师)，以及使用偏光显微镜和差示扫描量热法进行初始相分析，将在普吉特湾大学进行。为了确定每种衍生物中存在的双轴性程度，PI和他的学生将前往北卡罗来纳大学进行更复杂的分析(锥光显微镜和2H核磁共振波谱)。这项研究的主要目标是产生在相对较低温度下显示Nb相的衍生物，这将促进物理学家和工程师探索这些化合物的设备应用。非技术SUMMARY液晶显示器(LCD)广泛应用于笔记本电脑、手机和平板电视等各种应用中。呈现液晶相的化合物是这些显示器的组成部分；这一相中的分子通过产生对比度变化的电场来重新定向，从而允许产生图像。这项由这笔资金资助的研究的目的是研究一种特殊类型的液晶相，即双轴向列相。具体地说，目标是制备新的化合物，表明这一阶段的稳定性有所改善。双轴向列相是非常有意义的，因为使用具有该相的化合物组装LCD可以导致显著更快的响应时间。普吉特湾大学的本科生将直接参与这门具有重要技术意义的材料课程的所有方面的准备和表征。他们获得的经验将为化学或相关领域的研究生学习或直接在工业部门就业做好准备。这笔赠款还提供了一笔暑期津贴，允许塔科马社区学院(塔科马社区学院的学生群体多样化)的一名讲师参与研究过程。这一经历将使她能够更有效地向她的学生传达化学在技术中扮演的重要角色。此外，国际和平协会将访问社区学院，就液晶和其他材料科学主题发表演讲。

TECHNICAL SUMMARYThis RUI award to the University of Puget Sound from the Solid State and Materials Chemistry Program of the Division of Materials Research will allow for an in depth analysis of how structural changes in a series of oxadiazole and oxazole containing liquid crystals (LCs) impact the formation and stability of the biaxial nematic (Nb) phase. This unique LC phase, that was discovered in oxadiazole derivatives in 2004, may allow for faster electro-optic switching in LC displays. However, the original compounds show the Nb phase at impractically high temperatures. The awardee, Eric Scharrer, and his undergraduate students have demonstrated in preliminary work that the incorporation of lateral methyl groups into oxadiazole containing derivatives is a successful way to lower the nematic onset temperatures. The proposed research will involve systematically changing the position of various lateral groups (alkyl and halogen) to probe the effects of both steric and electronic factors on the biaxial nematic phase. Synthesis of the target compounds (by undergraduates and a community college instructor), and initial phase analysis, using polarizing microscopy and differential scanning calorimetry, will be carried out at the University of Puget Sound. In order to determine the degree of biaxiality present in each of the derivatives, the PI and his students will travel to the University of North Carolina to carry out more sophisticated analysis (conoscopic microscopy and 2H NMR spectroscopy). An overarching goal of the research is to generate derivatives that show the Nb phase at relatively low temperatures, which will facilitate the exploration of device applications of these compounds by physicists and engineers. NON-TECHNICAL SUMMARYLiquid crystal displays (LCD) are widely found in a variety of applications including laptop computers, cell phones, and flat screen televisions. Compounds that exhibit the liquid crystal phase are an integral component of these displays; molecules in this phase are reoriented by an electric field producing changes in contrast, thus allowing the production of images. The aim of the research funded by this grant is the investigation of a particular type of liquid crystal phase, the biaxial nematic phase. Specifically, the goal is to prepare new compounds that show improved stability of this phase. The biaxial nematic phase is of tremendous interest because assembly of an LCD using a compound possessing this phase may lead to significantly faster response times. Undergraduate students at the University of Puget Sound will be directly involved in all aspects of preparation and characterization of this technologically important class of materials. The experience they gain will be excellent preparation for graduate studies in Chemistry or a related field, or direct employment in the industrial sector. The grant also provides a summer stipend that will allow an instructor from Tacoma Community College (which has a diverse student population) to be involved in the research process. This experience will allow her to more effectively convey to her students how Chemistry plays an important role in technology. In addition, the PI will visit the community college to deliver presentations on liquid crystals and other materials science topics.