U.S.-Hungary Materials Research: Liquid Crystalline Mesophases of Bent Core Molecules

这个由肯特州立大学的Peter Palffy-Muhoray和匈牙利布达佩斯固体物理与光学研究所的Agnes Burka领导的美国-匈牙利研究项目研究了一类由弯曲分子组成的新型液晶。这些酯型弯芯液晶范围从低分子量材料到弹性体。合作研究计划包括这种弯核或香蕉形分子的合成、表征和建模。来自肯特州立大学的年轻研究人员是杰出的美国-匈牙利团队的一部分。为了确定弯核液晶的中间相和物理性质，研究伙伴将采用三种实验技术：1)薄膜的力学研究，包括香蕉液晶系统的线性机电和流变测量，其中整体手性由表面相互作用决定。2)电学测量，包括极化和介电光谱的测定。3)光学观测，包括偏光和共聚焦显微镜以及电光测量和激光光谱学。目标是解决一些关于材料参数与图案形成不稳定性之间关系的基本问题。例如，研究人员希望解释观察到的非手性对称性破坏机制，并了解结构如何在各向同性熔体中形成螺旋细丝。如果成功，他们的结果可能有助于识别具有光学和热释电特性的新型合成材料，这些材料在信息技术和生物技术中具有实际应用价值。这个实验凝聚态物理的研究项目通过使美国和中欧的专家在共同感兴趣和能力强的领域结合互补的人才和共享研究资源，实现了推进科学知识的计划目标。

This US-Hungarian research project headed by Peter Palffy-Muhoray of Kent State University and Agnes Burka of the Hungarian Institute for Solid State Physics and Optics Budapest examines a new class of liquid crystals consisting of bent-shaped molecules. These ester type bent core liquid crystals range from low molecular weight materials to elastomers. The collaborative research plan involves synthesis, characterization, and modeling of such bent-core, or banana-shaped, molecules. Junior researchers from Kent State University are part of the distinguished US-Hungarian team.To determine the mesophases and physical properties of bent-core liquid crystals, the research partners will employ three experimental techniques: 1)Mechanical studies of thin films including linear electro-mechanical and rheological measurements of banana liquid crystal systems, where the overall chirality is set by surface interactions. 2)Electrical measurements which include determination of the polarization and dielectric spectroscopy. 3)Optical observations consisting of polarizing and confocal microscopy as well as electro-optic measurements and laser spectroscopy. The goal is to resolve a number of fundamental questions concerning the correlation between material parameters and pattern forming instabilities. For example, the researchers hope to explain observed achiral symmetry-breaking mechanisms and to understand how the structures form helical filaments in an isotropic melt. If successful, their results may help identify novel synthetic materials with optical and pyroelectric properties that have practical applications in information technology and biotechnology. This research project in experimental condensed matter physics fulfills the program objective of advancing scientific knowledge by enabling experts in the United States and Central Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence.