RUI: Phase transitions of a single polymer chain: Effects of solvent, confinement, and tethering

RUI：单个聚合物链的相变：溶剂、限制和束缚的影响

• 批准号: 1204747
• 负责人: Mark Taylor
• 金额: $ 11.62万
• 依托单位: Hiram College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1204747&HistoricalAwards=false
• 关键词: RUI; Phase; transitions; single; polymer

TECHNICAL SUMMARYThis award made on an RUI proposal supports computational and theoretical research and education that addresses conformational phase transitions of single polymer molecules in response to variations in environmental variables such as temperature, pressure, or solution pH. This topic is of broad importance since both the bulk properties of polymer containing materials and the functionality of biopolymers and many polymer-based "smart" materials are directly determined by the underlying microscopic conformation of individual polymer molecules. Many smart or biologically active materials utilize polymer chains tethered to surfaces or nanoparticles. The effects of tethering and, more generally, confinement on single-chain phase transitions will also be investigated. This research continues and extends the recent work by the PI with significant contributions from undergraduate collaborators in the areas of solvent effects on polymer conformation and phase transitions of isolated homopolymer chains.The research objectives of this project are: (i) to elucidate the effects of local environment on the conformational phase transitions of a single polymer chain as relevant, for example, to the design and function of polymer based environmentally responsive smart materials; (ii) to study single-polymer phase transitions, in particular, the recently discovered homopolymer all-or-none "folding" transition, in simple models in order to establish the underlying physics of the universal aspects of protein folding; and (iii) to develop conformation and free energy landscapes using a rigorous microcanonical approach to study transition order, pathways, and kinetics of single-chain phase transitions. This work will make use of both the solvation potential approach, recently developed by the PI to reduce computational complexity in modeling polymer-solvent systems, and advanced simulation techniques that allow for direct computation of the density of states of classical many-body systems. The latter methods provide complete thermodynamic information and can be used to carry out subsequent multi-canonical simulations to determine structural information. This research contributes to the understanding of single-macromolecule behavior through the development of rigorous solvation potentials, density of states simulation methods, and microcanonical analysis techniques. It will contribute to efforts to develop rational design principles for functional polymer-based and biomimetic. This research program has been designed to allow for maximum student participation by dovetailing into the physics curriculum at Hiram College. Computation and simulation methods taught in the core courses establish a direct link between classroom learning and this research program and provide students with the tools needed to make meaningful contributions to this work. The undergraduate students who participate in this research will benefit by learning state of the art computer simulation techniques and will have opportunities to present at scientific meetings. Of the fourteen students who have worked with the PI at Hiram, twelve are now, or will be pursuing advanced study in physics, materials science, or engineering. This research proposal intends to continue such student successes and the PI hopes that these successes will help recruit more under-represented students into the sciences.NON-TECHNICAL SUMMARYThis award made on an RUI proposal supports computational and theoretical research and education to study transformations in the size and shape assumed by long chain-like molecules, polymers, as they respond to changes in their environment, such as changes in temperature and pressure. The PI will use advanced computer simulation techniques and models to advance understanding of this important problem. Changes in the size and shape of the polymers in living systems are often necessary to carry out functions at the biomolecular level to sustain life. A better understanding of this process contributes to developing design principles for smart materials that change their properties in response to changes in their environment in way that is reversible. Smart materials have many applications, including actuators, sensors, and a wide range of medical devices. This research program has been designed to allow for maximum student participation by dovetailing into the physics curriculum at Hiram College. Computation and simulation methods taught in the core courses establish a direct link between classroom learning and this research program and provide students with the tools needed to make meaningful contributions to this work. The undergraduate students who participate in this research will benefit by learning state of the art computer simulation techniques and will have opportunities to present at scientific meetings. Of the fourteen students who have worked with the PI at Hiram, twelve are now, or will be pursuing advanced study in physics, materials science, or engineering. This research proposal intends to continue such student successes and the PI hopes that these successes will help a recruit more under-represented students into the sciences.

技术总结根据RUI的一项提议颁发的这一奖项支持计算和理论研究和教育，这些研究和教育旨在解决单个聚合物分子的构象相变问题，以响应环境变量的变化，如温度、压力或溶液pH。这一主题具有广泛的重要性，因为含有聚合物的材料的整体性质以及生物聚合物和许多基于聚合物的“智能”材料的功能都直接由单个聚合物分子的基本微观构象决定。许多智能或生物活性材料利用连接在表面或纳米颗粒上的聚合物链。我们还将研究系链和更一般的限制对单链相变的影响。这项研究继续和扩展了PI最近的工作，本科生合作者在溶剂对聚合物构象的影响和孤立的均聚物链的相变方面做出了重大贡献。本项目的研究目标是：(I)阐明局部环境对单个聚合物链构象相变的影响，例如，与基于聚合物的环境响应智能材料的设计和功能相关；(Ii)在简单的模型中研究单个聚合物的相变，特别是最近发现的均聚物全有或无“折叠”相变，以建立蛋白质折叠普遍方面的基本物理学；以及(Iii)用严格的微正则方法研究单链相变的跃迁顺序、途径和动力学，建立构象和自由能景观。这项工作将利用PI最近开发的溶剂化势法来降低聚合物-溶剂系统建模的计算复杂性，以及允许直接计算经典多体系统的态密度的高级模拟技术。后一种方法提供了完整的热力学信息，并可用于执行后续的多正则模拟以确定结构信息。这项研究通过发展严格的溶剂化势、态密度模拟方法和微正则分析技术来帮助理解单大分子的行为。这将有助于开发基于功能聚合物和仿生材料的合理设计原则。这项研究计划旨在通过与希拉姆学院的物理课程相衔接，最大限度地让学生参与进来。核心课程中教授的计算和模拟方法在课堂学习和这项研究计划之间建立了直接联系，并为学生提供了为这项工作做出有意义贡献所需的工具。参与这项研究的本科生将从学习最先进的计算机模拟技术中受益，并将有机会在科学会议上发表演讲。在希拉姆与PI一起工作的14名学生中，有12名现在或将在物理学、材料科学或工程学方面深造。这项研究计划继续取得这样的学生成功，国际学生联合会希望这些成功将有助于招收更多未被充分代表的学生进入科学界。非技术总结这个奖项基于RUI建议，支持计算和理论研究以及教育，以研究长链状分子和聚合物在对环境变化(如温度和压力的变化)做出反应时，其大小和形状的变化。PI将使用先进的计算机模拟技术和模型来促进对这一重要问题的理解。生命系统中聚合物的大小和形状的变化对于在生物分子水平上实现维持生命的功能通常是必要的。对这一过程的更好理解有助于制定智能材料的设计原则，这种设计原则可以随着环境的变化而改变其性质，这种方式是可逆的。智能材料有许多应用，包括执行器、传感器和广泛的医疗设备。这项研究计划旨在通过与希拉姆学院的物理课程相衔接，最大限度地让学生参与进来。核心课程中教授的计算和模拟方法在课堂学习和这项研究计划之间建立了直接联系，并为学生提供了为这项工作做出有意义贡献所需的工具。参与这项研究的本科生将从学习最先进的计算机模拟技术中受益，并将有机会在科学会议上发表演讲。在希拉姆与PI一起工作的14名学生中，有12名现在或将在物理学、材料科学或工程学方面深造。这项研究计划旨在延续这种学生的成功，国际学生联合会希望这些成功将有助于招收更多未被充分代表的学生进入科学界。