Solution and Interfacial Properties of Catenated Polymers

非技术总结门链、防滑链、锚索、珠宝项链和锁子甲都由相互连接的金属环组成。由于它们的互锁结构，这些材料结合了联合收割机的灵活性和机械强度。类似的互锁结构，由两个或更多个相互缠绕的环组成，也可以通过化学合成在分子水平上产生，其中每个环仅由一个单一分子组成，称为聚合物或大环。过去，这些所谓的索烃和聚索烃的合成限于短链和低产率。然而，合成的最新进展正在将聚链烷合成的限制推到新的复杂性和再现性水平，为在纳米级应用中使用聚链烷打开了大门，例如分子马达，可编程电子开关和致动器。由于聚链烷代表了一种新型的聚合物基结构，对其材料性质的基本理解仍然有限。该奖项支持旨在促进对链烷和聚链烷在溶液和界面中行为的基本理解的理论和计算研究和教育。主要研究人员正在使用最先进的计算机模拟方法和机器学习技术来设计和优化互锁聚合物结构的模型，并使用它们来阐明聚链烷在特定应用中的材料特性。这项研究扩展了目前的前沿中尺度和多尺度建模的方法，通知纳米级分子组装的设计。该项目吸引了研究生，通过高分子科学和高分子工程学院的NSF-REU中心的本科生，以及来自俄亥俄州阿克伦地区的高中生。主要研究者和研究生将访问当地学校，为大量的少数民族提供服务，并鼓励这群学生参加科学课程，并追求STEM的职业生涯。技术总结这个NSF奖项支持理论和计算研究和教育，旨在推进对被称为catenanes和polycatenanes的聚合物结构的基本理解。链烯与更复杂的聚链烯一起代表通过机械键而不是通常决定聚合物性质的共价键保持在一起的机械互锁聚合物结构。PI将采用基于珠弹簧粗粒模型的分子模拟技术，以研究和合理化索烃在溶液中和界面处的材料性质。具体项目的目标是链状聚合物通过窄孔的移位，链状聚合物刷中的张力分布，以及机器学习引导的链状烃介观模型的开发。这项研究提供了基础，包括索烃的聚合物结构的介观和多尺度建模，从而扩展了目前的前沿模拟复杂的超分子组装。该项目涉及研究生以及本科生通过NSF-REU中心在聚合物科学和聚合物工程学院，和高中学生从阿克伦，俄亥俄州地区。该奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

NONTECHNICAL SUMMARYDoor chains, snow chains, anchor cables, jewelry necklaces, and chain mail all consist of interconnected metal rings. Because of their interlocked structure, these materials combine flexibility with mechanical strength. Similarly interlocked structures, consisting of two or more intertwined rings, can also be produced on a molecular level by chemical synthesis, where each ring consists of only one single molecule, known as polymer or macrocycle. In the past, the synthesis of these so-called catenanes and polycatenanes has been limited to short chains and low yields. Recent advances in synthesis, however, are pushing the limits of polycatenane synthesis to new levels of complexity and reproducibility, opening a door toward using polycatenanes in nano-scale applications such as molecular motors, programmable electronic switches, and actuators. Because polycatenanes represent a new type of polymer-based architecture, basic understanding of their material properties remains limited.This award supports theoretical and computational research and education aimed at advancing the fundamental understanding of how catenanes and polycatenanes behave in solution and at interfaces. The principal investigator is using state-of-the-art computer simulation methods and machine learning techniques to design and optimize models for interlocked polymeric architectures and use them to elucidate the material properties of polycatenanes in specific applications. This research extends the current frontier of mesoscale and multiscale modeling as a method of informing the design of nanoscale molecular assemblies. The project engages graduate students, undergraduate students through the NSF-REU center at the School of Polymer Science and Polymer Engineering, and high school students from the Akron, Ohio area. The principal investigator and the graduate students supported by this grant will visit local schools that are serving large numbers of minorities and will encourage this group of students to take science courses and pursue careers in STEM.TECHNICAL SUMMARYThis NSF award supports theoretical and computational research and education aimed at advancing the fundamental understanding of polymer architectures known as catenanes and polycatenanes. Catenanes, together with the more complex polycatenanes, represent mechanically interlocked polymeric structures that are held together by mechanical bonds, not by covalent bonds that usually determine the properties of polymers. The PI will employ molecular simulation techniques based on a bead-spring coarse-grained model to investigate and rationalize the material properties of catenanes in solution and at interfaces. Specific projects target the translocation of catenated polymers through narrow pores, the tension distribution in catenated polymer brushes, and the development of machine learning-guided mesoscale models for catenanes. This research provides groundwork for including catenanes into the mesoscale and multiscale modeling of polymeric architectures and thus extends the current frontier of simulating complex supramolecular assemblies. The project involves graduate students as well as undergraduate students through the NSF-REU center at the School of Polymer Science and Polymer Engineering, and high school students from the Akron, Ohio area.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.