Collaborative Research: Highly ordered concentric multilayer nanostructures with probable liquid crystalline features from rigid sphere-rod amphiphiles in solution

合作研究：溶液中刚性球棒两亲物具有可能液晶特征的高度有序同心多层纳米结构

• 批准号: 2215190
• 负责人: Tianbo Liu
• 金额: $ 51.86万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2215190&HistoricalAwards=false
• 关键词: Collaborative; Research; Highly; ordered; concentric

Non-technical Summary With support from the Solid State and Materials Chemistry program as well as the Condensed Matter Physics program, both in the Division of Materials Research, this project combines experimental and computational research and education aimed at advancing the fundamental understanding of how rigid block copolymers behave and self-organize in solution to liquid crystals. Liquid crystal is a state of matter between fluid liquids and solid crystals, and broadly used as display devices in TV screens (LCD), cell phones and contact lenses. Block copolymers are formed by linking two or more different long chain polymers together. Different blocks often possess different properties such as solubility, which lead block copolymers to self-organize into various nanometer-scale structures and make them important materials in drug delivery, coating and lubrication. While block copolymers with flexible chains have been well studied, those with fully rigid components are poorly understood. Investigators from the University of Akron and Kent State University design and study fully rigid block copolymers with special shapes for each block. This fundamental investigation enables the researchers to understand how these rigid copolymers behave in solution, what types of supramolecular structures they can self-organize into, and how the structure formations are controlled by temperature, solvent, as well as the shape and architecture of copolymers. The team focuses in particular on exploring the possible liquid crystal features emerging from such rigid block copolymer assemblies. The team examines a probable new type of liquid crystals formed by rigid block copolymers and their potential applications as materials through a series of experiments and complementary computer simulations. Furthermore, the project engages graduate students, undergraduate students through the NSF-REU center at the School of Polymer Science and Polymer Engineering at the University of Akron, and high school students from the Akron-Kent areas in Ohio. Graduate students from both institutions supported by this grant can expand their experience by mutual visits, collaborative experiments and discussions. The team also visits local schools that are serving large numbers of minorities and encourage students to take science courses and pursue careers in STEM.Technical SummarySupported by the Solid State and Materials Chemistry program as well as the Condensed Matter Physics program, both in the Division of Materials Research, Professors Liu and Tsige at University of Akron, along with Professor Lavrentovich at Kent State University, team up to explore the self-assembly of fully rigid, sphere-rod shaped amphiphilic block copolymers. Such rigid copolymers demonstrate completely different assembly behaviors from the well-studied flexible block copolymers, by forming uniform, onion-like, multilayer concentric assemblies with identical, well-defined inter-layer distance. The assemblies respond to the change of solvent polarity, temperature and others by changing the number of layers while maintaining the overall structure and inter-layer distance. The project includes the following objectives which are pursued by combining experimental characterizations and computer simulations: (1) investigation of the mechanism and driving forces of this novel onion-like assembly and the reason for the uniform assembly size; (2) elucidation of the rational control of their size (number of layers) via changing solvent, counterions or temperature; (3) studying the effects of rod length, rod number, sphere size/shape, and rod orientation on the self-assembly, and (4) determination whether these onion-like supramolecular structures possess liquid crystalline features, and if so, how these unique features impact liquid crystal science and technology. The research expands the fundamental understanding of block copolymer materials (from flexible ones to rigid ones) and liquid crystals, as well as their potential applications as functional materials.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.

在材料研究部固态和材料化学项目以及凝聚态物理项目的支持下，该项目将实验和计算研究与教育相结合，旨在推进对刚性嵌段共聚物在液晶溶液中的行为和自组织的基本理解。液晶是介于液态和固态之间的一种物质状态，广泛用作电视屏幕（LCD）、手机和隐形眼镜的显示器件。嵌段共聚物是由两种或多种不同的长链聚合物连接在一起而形成的。不同的嵌段往往具有不同的性质，如溶解度，这使得嵌段共聚物自组织成各种纳米级结构，使其成为药物递送、涂层和润滑的重要材料。虽然具有柔性链的嵌段共聚物已经得到了很好的研究，但那些具有完全刚性组分的嵌段共聚物却知之甚少。阿克伦大学和肯特州立大学的研究人员设计和研究了具有特殊形状的全刚性嵌段共聚物。这项基础研究使研究人员能够了解这些刚性共聚物在溶液中的行为，它们可以自组织成哪种类型的超分子结构，以及结构形成如何受温度，溶剂以及共聚物的形状和结构的控制。该团队特别专注于探索从这种刚性嵌段共聚物组件中出现的可能的液晶特征。该团队通过一系列实验和互补的计算机模拟，研究了一种可能由刚性嵌段共聚物形成的新型液晶及其作为材料的潜在应用。此外，该项目还招收研究生，本科生通过阿克伦大学高分子科学与高分子工程学院的NSF-REU中心，以及来自俄亥俄州阿克伦-肯特地区的高中生。获资助的两校研究生可以通过互访、合作实验和讨论等方式拓展经验。该团队还访问了为大量少数民族提供服务的当地学校，并鼓励学生参加科学课程并从事STEM职业。在材料研究部固态和材料化学项目以及凝聚态物理项目的支持下，阿克伦大学的Liu教授和Tsige教授以及肯特州立大学的Lavrentovich教授共同探索了全刚性、球棒状两亲嵌段共聚物的自组装。这种刚性共聚物的组装行为与研究得很好的柔性嵌段共聚物完全不同，它们形成均匀的、洋葱状的多层同心共聚物，层间距离相同，定义明确。该组件通过改变层数来响应溶剂极性、温度等因素的变化，同时保持整体结构和层间距离。本项目通过实验表征和计算机模拟相结合，实现了以下目标：(1)研究这种新型洋葱状组装的机理和驱动力，以及组装尺寸均匀的原因；(2)阐明通过改变溶剂、反离子或温度来合理控制其尺寸（层数）；(3)研究棒材长度、棒材数量、球体大小/形状和棒材方向对自组装的影响；(4)确定这些类似洋葱的超分子结构是否具有液晶特征，如果具有液晶特征，这些独特的特征如何影响液晶科学与技术。该研究扩展了对嵌段共聚物材料（从柔性材料到刚性材料）和液晶的基本理解，以及它们作为功能材料的潜在应用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。