Arrays of Molecular Dipolar Rotors

分子偶极转子阵列

• 批准号: 1608424
• 负责人: Josef Michl
• 金额: $ 43.5万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1608424&HistoricalAwards=false
• 关键词: Arrays; Molecular; Dipolar; Rotors

Non-technical AbstractWith the support from the Solid State and Materials Chemistry program, the research team will work on an interdisciplinary project in design-directed material synthesis that calls for close interactions with colleagues in the Physics department. The project aims to prepare and characterize a so far unknown class of dielectric materials based on artificial dipolar molecular rotors arranged in a 2-dimensional grid. Such materials do not occur in nature and would be useful for signal processing and specifically for minituarization of analog components in electronic circuitry such as that found in cellular telephones. A post-doctoral student and several undergraduates will receive interdisciplinary training (organic synthesis, a variety of spectroscopic and other physical techniques, and underlying materials theory). The project will attract undergraduate students, K-12 students, and under-represented minorities to nanoscience.Technical AbstractThe new 2-dimensional materials are to be assembled on a Langmuir-Blodgett (LB) trough and transferred to a lithographically patterned solid substrate. The specifically synthesized rod-like rotor molecules carry a dipolar rotator between two triptycene units on an axle normal to the surface, and a carboxylic group at one end (the term molecular rotor is used for a molecule with a rotatable part, which is called the rotator). Initial grazing-incidence X-ray scattering and other data demonstrate that molecules of this type self-assemble into a Langmuir monolayer on an aqueous subphase. The structure of the assembly is characterized by an interlocking of the triptycene units into a double-decker trigonal pattern, with almost freely rotatable dipoles between the decks. The distance between the dipoles and their magnitude are such that as long as sufficiently large 2-dimensional single-crystal domains can be prepared, in the first approximation the ground state should be ferroelectric, with a Curie temperature above ambient. Rotator dynamics in the transferred monolayers (and multilayers) are to be studied by electric dichroism in the infrared part of the spectrum in the Michl laboratory and by dielectric spectroscopy in the Rogers laboratory. Theory predicts the existence of ferroelectric ordering with unusually low velocity polar sound waves when long-range dipolar interactions dominate local steric barriers to rotation.

非技术摘要在固态和材料化学项目的支持下，研究小组将致力于设计导向材料合成的跨学科项目，该项目需要与物理系的同事密切互动。 该项目旨在制备和表征一种迄今未知的基于人工偶极分子转子排列在二维网格中的介电材料。 这样的材料在自然界中不存在，并且将用于信号处理，特别是用于电子电路（例如在蜂窝电话中发现的电子电路）中的模拟元件的小型化。 一名博士后和几名本科生将接受跨学科培训（有机合成，各种光谱和其他物理技术，以及基础材料理论）。 该项目将吸引本科生，K-12的学生，和代表性不足的少数民族nanoscience.Technical Abstract新的2维材料是组装在一个朗缪尔-布洛杰特（LB）槽和转移到光刻图案的固体基板。 特别合成的棒状转子分子在垂直于表面的轴上的两个三蝶烯单元之间携带偶极旋转体，并且在一端携带羧基（术语分子转子用于具有可旋转部分的分子，其被称为旋转体）。 初始掠入射X射线散射和其他数据表明，这种类型的分子自组装成一个朗缪尔单层上的水亚相。 该组件的结构特征在于三蝶烯单元互锁成双层三角形图案，在甲板之间具有几乎可自由旋转的偶极子。 偶极子之间的距离和它们的大小是这样的，只要可以制备足够大的二维单晶畴，在第一近似下，基态应该是铁电的，居里温度高于环境温度。 在转移的单层（和多层）的旋转动力学进行了研究，在Michl实验室的光谱的红外部分的电二色性和介电光谱在罗杰斯实验室。 理论预测的铁电有序异常低速极性声波的存在时，远程偶极相互作用占主导地位的本地位阻旋转。