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

技术总结该奖项基于RUI的提案，支持计算和理论研究和教育，解决单个聚合物分子响应环境变量（如温度，压力，这一主题具有广泛的重要性，因为包含材料的聚合物的本体性质和生物聚合物的功能性以及许多基于聚合物的“智能”聚合物都是重要的。材料直接由单个聚合物分子的潜在微观构象决定。许多智能或生物活性材料利用拴系到表面或纳米颗粒的聚合物链。 拴系，更一般地说，限制单链相变的影响也将被调查。本研究延续并扩展了PI最近的工作，并在溶剂对聚合物构象和孤立均聚物链相变的影响方面与本科合作者做出了重大贡献。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相关影响，例如，以聚合物为基础的环境响应智能材料的设计和功能;（ii）研究单一聚合物相变，特别是最近发现的均聚物全或无“折叠”过渡，在简单的模型，以建立蛋白质折叠的普遍方面的基本物理;和（iii）开发构象和自由能景观使用严格的微正则方法来研究过渡顺序，途径和动力学的单链相变。这项工作将利用两个溶剂化势的方法，最近开发的PI，以减少计算复杂性建模聚合物溶剂系统，和先进的模拟技术，允许直接计算的状态密度的经典多体系统。后一种方法提供了完整的热力学信息，并可用于进行后续的多正则模拟，以确定结构信息。这项研究有助于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理解单个大分子的行为。这将有助于发展合理的设计原则，为功能性聚合物基和仿生。这项研究计划的目的是让学生最大限度地参与到希拉姆学院的物理课程。核心课程中教授的计算和模拟方法建立了课堂学习和本研究计划之间的直接联系，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受益于学习最先进的计算机模拟技术，并将有机会出席科学会议。在希拉姆与PI合作的14名学生中，有12名现在或将要在物理学、材料科学或工程学方面进行深造。这项研究计划旨在继续这样的学生成功，PI希望这些成功将有助于招募更多的代表性不足的学生进入科学领域。非技术总结RUI建议的这个奖项支持计算和理论研究和教育，以研究长链状分子，聚合物，随着它们对环境变化的反应，例如温度和压力的变化。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。在生命系统中，聚合物的大小和形状的变化通常是在生物分子水平上执行功能以维持生命所必需的。更好地理解这一过程有助于开发智能材料的设计原则，这些智能材料可以可逆地改变其特性以响应环境的变化。智能材料有许多应用，包括致动器，传感器和广泛的医疗设备。这项研究计划的目的是让学生最大限度地参与到希拉姆学院的物理课程。核心课程中教授的计算和模拟方法建立了课堂学习和本研究计划之间的直接联系，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受益于学习最先进的计算机模拟技术，并将有机会出席科学会议。在希拉姆与PI合作的14名学生中，有12名现在或将要在物理学、材料科学或工程学方面进行深造。这项研究计划旨在继续这种学生的成功，PI希望这些成功将有助于招募更多代表性不足的学生进入科学领域。

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.