Quantifying and manipulating chirality and amplification of nanomaterials in liquid crystals

量化和操纵液晶中纳米材料的手性和放大

• 批准号: 1904091
• 负责人: Torsten Hegmann
• 金额: $ 31.98万
• 依托单位: Kent State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1904091&HistoricalAwards=false
• 关键词: Quantifying; manipulating; chirality; amplification; nanomaterials

NON-TECHNICAL SUMMARYChirality, most simply described by the absence of mirror symmetry, can be found everywhere in nature and probably in the universe. Established as a term by Lord Kelvin in 1894, and significantly advanced by Pasteur and others, chirality has significant implications in Chemistry, Biology, Physics, Cosmology, and Materials Science alike. Described as "universal asymmetry" by Wagniere, the origin of homochirality of life is one of the most central scientific questions. Amplification of chirality underpins most theories proposed to describe nature's homochirality, i.e. the use of exclusively one enantiomer (one handedness) of sugars and amino acids to build all life forms, from simple to complex. This project, supported by the Solid State and Materials Chemistry program as well as the Condensed Matter Physics program at NSF, advances recent findings that chirality emanating from nanoscale particles capped with a monolayer of chiral molecules is uniquely able to generate more intense responses in liquid crystals than their organic molecular chiral counterparts. The liquid crystalline state, pervasive in nature just like chirality, here serves as a powerful test platform to establish size-property and shape-property relationships governing the amplification of chirality through space. This research at Kent State University generates data that advance the understanding of nanoscale chirality and paves the way for new applications of nanoscale materials as chirality sensors, tunable chiral metamaterials, and chiral catalysts. Students experience a multidisciplinary training environment, utilize state-of-the-art equipment, and become proficient in presenting their research to peers. The project serves as a platform for several outreach activities including training of high school students, hands-on lectures and lab research for community college students, and a scientific symposium.TECHNICAL SUMMARYSignificant advances in the understanding and application of the unique features of nanomaterial chirality are only possible if one can detect, measure, visualize, tune, and transfer nanomaterial chirality through space and across length scales. To study this, the ubiquitous liquid crystalline state offers unrivaled opportunities for both fundamental theoretical and applied experimental research on nanomaterial chirality, by permitting the visualization as well as quantification of chirality amplification at different length scales. A range of imaging techniques such as polarized optical microscopy, fluorescence confocal microscopy, and transmission electron microcopy are used to study these systems. Guided by first principle theoretical calculations of a pseudoscalar chirality index, this experimental work also establishes how chirality amplification at the nanoscale depends on the nanomaterial type, size, shape, and aspect ratio. The team synthesizes, characterizes, and studies chiral ligand-capped metal nanorods, nanodiscs, nanostars, nanotriangles, and nanocages decorated with chiral ligand shells in nematic liquid crystals, and compares experimental data of the helical twisting power to theoretical values of the calculated chirality index. To test how chirality amplification can be applied, chiral nematic microlens arrays similar to arthropod or compound eyes are created, and the use of magnetic fields in combination with anisometric chiral molecule-capped magnetic nanoparticles dispersed in nematic liquid crystal phases examined. The latter seeks to understand how competing elastic and magnetic forces of liquid crystal host and dispersed magnetic nanoparticles, respectively, can be translated into motion.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要术，最简单地从缺乏镜子对称性的情况下描述，可以在自然界和宇宙中的任何地方找到。 Haillity于1894年由Kelvin勋爵（Lord Kelvin）成立，并由巴斯德（Pasteur）和其他人建立，对化学，生物学，物理学，宇宙学和材料科学都具有重要意义。瓦格尼尔（Wagniere）被描述为“普遍的不对称”，生命的同源性的起源是最中心的科学问题之一。大多数提议描述自然同质病的理论的基础，即仅使用一种糖（一只手）糖和氨基酸来构建从简单到复杂的所有生命形式的使用。该项目在NSF的固态和材料化学计划以及凝结物理学计划的支持下，进展到最近的发现，即用手性分子单层封闭的纳米级颗粒的手性能是唯一能够在液晶中产生更强烈的反应的。比它们的有机分子手性对应物。液晶状态在本质上像手性一样普遍存在，这里是一个强大的测试平台，以建立尺寸质量和形状 - 陶艺关系，控制了通过太空扩增手性的。肯特州立大学的这项研究生成了数据，可以提高对纳米级手性的理解，并为纳米级材料作为手性传感器，可调节性手性地材料和手性催化剂的新应用铺平道路。学生体验多学科的培训环境，利用最先进的设备，并熟练地向同龄人展示他们的研究。该项目是多项外展活动的平台仅当人们可以检测，测量，可视化，调整和传递纳米材料手性通过空间和长度尺度。为了研究这一点，无处不在的液晶状态通过允许可视化和定量在不同长度尺度下的手性放大，为基本理论和应用实验研究提供了无与伦比的机会。一系列成像技术，例如极化光学显微镜，荧光共聚焦显微镜和透射电子微映射，用于研究这些系统。在伪级手性指数的第一个原理理论计算的指导下，这项实验工作还确定了纳米级的手性放大如何取决于纳米材料类型，大小，形状和纵横比。团队综合，特征和研究手性配体金属纳米棒，纳米轴，纳米轴，纳米尺，纳米三角形和纳米腔，用刺激性液晶中的手性配体壳装饰，并比较螺旋式扭曲量的实验性数据，并比较定位的旋转量的实验性数据。 。为了测试如何应用手性扩增，形成了类似于节肢动物或复合眼类似的手性列源微片阵列，并结合使用在鉴定在nematic液晶相中的磁场结合使用磁场与动态性手性分子覆盖的磁性纳米颗粒。后者试图理解液晶宿主和分散磁性纳米颗粒的竞争性弹性和磁力如何被转化为运动。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和广泛评估的支持的。影响审查标准。

项目成果

Molecular Conformation of Bent-Core Molecules Affected by Chiral Side Chains Dictates Polymorphism and Chirality in Organic Nano- and Microfilaments

• DOI: 10.1021/acsnano.1c00527
• 发表时间: 2021-03-18
• 期刊: ACS NANO
• 影响因子: 17.1
• 作者: Liu, Jiao;Shadpour, Sasan;Hegmann, Torsten
• 通讯作者: Hegmann, Torsten

Optical properties of nematic microlenses doped with chiral nanoparticles

• DOI: 10.1117/12.2568570
• 发表时间: 2020-08
• 作者: Kelum Perera;Alham Nemati;E. Mann;T. Hegmann;A. Jákli

Recent progress at the interface between nanomaterial chirality and liquid crystals

• DOI: 10.1080/21680396.2021.1930596
• 发表时间: 2021-01
• 期刊: Liquid Crystals Reviews
• 影响因子: 5.1
• 作者: Diana P. N. Gonçalves;M. Prévôt;Şenay Üstünel;Timothy Ogolla;Ahlam Nemati;Sasan Shadpour;T. Hegmann

Binary mixtures of bent-core molecules forming distinct types of B4 phase nano- and microfilament morphologies

• DOI: 10.1080/02678292.2020.1847333
• 发表时间: 2020-11
• 期刊: Liquid Crystals
• 影响因子: 2.2
• 作者: Jiao Liu;Sasan Shadpour;Ahlam Nemati;M. Prévôt;E. Hegmann;Chenhui Zhu;T. Hegmann

The significance of nanoparticle shape in chirality transfer to a surrounding nematic liquid crystal reporter medium

纳米粒子形状在手性转移到周围向列液晶报告介质中的重要性

• DOI: 10.1039/d2ma00093h
• 发表时间: 2022
• 期刊: Materials Advances
• 影响因子: 5
• 作者: Sharma, Anshul;Mori, Taizo;Nemati, Ahlam;Gonçalves, Diana P.;Querciagrossa, Lara;Zannoni, Claudio;Hegmann, Torsten
• 通讯作者: Hegmann, Torsten