Solution and Interfacial Properties of Catenated Polymers

非技术的SummaryDoor链、雪链、锚索、珠宝项链和锁链都是由相互连接的金属环组成的。由于其相互关联的结构，这些材料将灵活性与机械强度结合在一起。同样，由两个或多个相互缠绕的环组成的互锁结构也可以通过化学合成在分子水平上产生，其中每个环只由一个称为聚合物或大环的单一分子组成。过去，这些所谓的环戊烷和聚环己烷的合成一直局限于短链和低产率。然而，合成方面的最新进展正在将聚并戊二烯的合成限制推向新的复杂性和重复性水平，为将聚并戊二烯用于纳米级应用打开了大门，如分子马达、可编程电子开关和执行器。由于聚环己烷代表了一种新型的基于聚合物的结构，对其材料性质的基本了解仍然有限。该奖项支持理论和计算研究和教育，旨在促进对链烷和聚环己烷在溶液和界面上的行为的基本理解。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，并使用它们来阐明特定应用中的聚环戊二烯的材料性质。这项研究扩展了当前中尺度和多尺度建模的前沿，作为一种指导纳米级分子组装设计的方法。该项目吸引了研究生，通过聚合物科学和聚合物工程学院的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。首席研究员和该基金资助的研究生将访问当地为大量少数族裔服务的学校，并将鼓励这群学生参加科学课程并在STEM从事职业生涯。技术总结该NSF奖支持旨在促进对聚合物体系结构(即聚环己烷和聚环戊二烯)的基本理解的理论和计算研究和教育。链烷与更复杂的聚链烷一起，代表了通过机械键而不是通常决定聚合物性质的共价键连接在一起的机械联锁的聚合物结构。PI将使用基于珠状弹簧粗粒模型的分子模拟技术来研究和合理化溶液中和界面上的链烷的材料性质。具体项目的目标是链状聚合物通过狭孔的转移，链状聚合物刷子中的张力分布，以及开发机器学习指导的链烷中尺度模型。这项研究为将链烷纳入聚合物结构的介观和多尺度模拟奠定了基础，从而扩展了目前模拟复杂超分子组装的前沿。该项目涉及聚合物科学和聚合物工程学院NSF-REU中心的研究生和本科生，以及来自俄亥俄州阿克伦地区的高中生。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.