Polymer networks to induce deformations and topological defects in liquid crystals

引起液晶变形和拓扑缺陷的聚合物网络

• 批准号: 2004532
• 负责人: Francesca Serra
• 金额: $ 44.76万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004532&HistoricalAwards=false
• 关键词: Polymer; networks; induce; deformations; topological

Non-technical Description:Liquid crystals are not only interesting for their role at the foundation of the 100-billion-dollar display industry. They are ideal materials to create soft structures that are controllable with external stimuli, and they provide a platform for physicists and chemists to address fundamental scientific questions. Unlike disordered molecules in common fluids, molecules in liquid crystals have some amount of order. Different types of liquid crystals have significant variability in terms of molecular structure and arrangement, which results in different mechanical and optical properties. Understanding the differences and the similarities between liquid crystal phases opens new paths to create not only the next generation of liquid crystal displays but also of a broader range of liquid crystal-based nanomaterials; furthermore, it helps answering fundamental questions regarding transitions between different states of matter. The goal of this research is to quantify the similarities and differences between liquid crystal phases by using polymers as mediators. Polymers can be dispersed in liquid crystals to create an “imprint” of the molecular order, which can then be transferred to a different liquid crystal. The goal is to devise a new classification method by measuring the compatibility of liquid crystal phases to accommodate distortions in the molecular ordering seen in other liquid crystal phases. The impact of this project extends beyond the physics community. Aligned networks of polymers are present in biological systems, and this project helps elucidate the role they have in tissues. Moreover, the broader goals of this project involve the creation of lightweight materials with customizable properties. In terms of societal impact, one goal is to involve young students and the general public through outreach events about liquid crystals, whose visual appeal makes them effective for illustrating science concepts. This project also aims to provide the basis for several undergraduate theses, including theses by under-represented minority students enrolled in a departmental bridge program in collaboration with Baltimore-area colleges. Technical Description:This research project uses polymer networks templated in liquid crystals to impose deformation on other liquid crystal phases. Templated polymer networks can be obtained by dispersing monomers in low concentration in liquid crystals. Once cross-linked, the polymers carry the memory of the alignment. If the liquid crystal is removed from the polymer network, the same network can be re-filled with another material, which will have to comply with the deformations imposed by the polymers. The project has various goals, which include (a) the creation of templated polymer networks with specific distortions, (b) the analysis of the same networks re-filled with different kinds of liquid crystals, and (c) the quantitative measure of compatibility between the distortions and the identification of a “distance” between phases that provides a new classification method of liquid crystal phases. Other project goals involve using aligned polymer networks for 4D printing or as lightweight material for applications in biology or energy storage. Characterization of the liquid crystals are performed with optical microscopy, combined with electron microscopy and small angle x-ray scattering.This Division of Materials Research (DMR) grant supports research to study phase structure and ordering in liquid crystals with funding from the Condensed Matter Physics (CMP) Program in DMR of the Mathematical and Physical Sciences (MPS) Directorate.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.

非技术描述：液晶不仅因其在100亿美元的展示行业的基础上的作用而有趣。它们是创建由外部刺激控制的软结构的理想材料，它们为物理学家和化学家提供了一个平台，以解决基本的科学问题。与普通流体中的分子无序分子不同，液晶中的分子具有一定程度的顺序。不同类型的液晶在分子结构和排列方面具有显着可变性，从而导致不同的机械和光学特性。了解液晶相之间的差异和相似性，开辟了新的路径，不仅创建了下一代液晶显示器，而且还创建了更广泛的液晶纳米材料。此外，它有助于回答有关物质不同状态之间过渡的基本问题。这项研究的目的是通过使用聚合物作为介体来量化液晶相之间的相似性和差异。可以将聚合物分散在液晶中，以产生分子顺序的“烙印”，然后可以将其转移到不同的液晶中。目的是通过测量液晶相的兼容性来制定一种新的分类方法，以适应其他液晶相中看到的分子排序中的扭曲。该项目的影响范围超出了物理界。聚合物的一致性网络存在于生物系统中，该项目有助于阐明它们在组织中的作用。此外，该项目的更广泛的目标涉及创建具有可自定义属性的轻质材料。在社会影响方面，一个目标是通过有关液晶的外展活动使年轻学生和公众参与，其视觉外观使它们有效地说明了科学概念。该项目还旨在为几个本科论文提供基础，包括由代表不足的少数民族学生与巴尔的摩地区学院合作参加了一项部门桥梁计划的基础。技术描述：该研究项目使用在液晶中模板的聚合物网络对其他液晶相施加变形。可以通过将低浓度的单体分散在液晶中来获得模板聚合物网络。一旦交联后，聚合物带有对齐的记忆。如果从聚合物网络中除去液晶，则可以将同一网络重新填充另一种材料，该材料必须符合聚合物施加的变形。该项目具有各种目标，其中包括（a）创建具有特定变形的模板聚合物网络，（b）对同一网络重新填充不同种类的液晶的分析，以及（c）在扭曲和识别液体水晶层的新阶段之间识别扭曲和识别距离之间相容性的定量度量。其他项目目标涉及使用对齐聚合物网络进行4D打印或作为生物学或能源存储应用的轻量级材料。液晶的表征是通过光学显微镜进行的，结合了电子显微镜和较小的角度X射线散射。本材料研究（DMR）授予的拨款支持研究研究相结构和液晶中的序列结构和批准物质物理学资金（CMP）计划（CMP）计划的数学和物理统计局（CMP）的资金（MMP），并授予MIDSERDERSED ever.mps ever.mps ever.mps ever.mps ever.mps。通过使用基金会的知识分子和更广泛影响的评论标准来通过评估来支持。