RUI: Collapse and folding of a polymer chain: Effects of crowding and confinement

非技术性总结该奖项基于本科研究所（RUI）的一项研究提案，支持计算和理论研究和教育，以研究长链状分子，聚合物在响应环境变化（如温度和压力变化）时的大小和形状变化。 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。 生物细胞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中。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。许多学生谁曾与PI在希拉姆，已经或将要在物理学，材料科学，工程学，或医学追求先进的研究。 PI旨在继续为学生提供成功的教育经验，并帮助招募更多代表性不足的学生进入科学领域。技术总结该奖项是基于本科院校研究（RUI）提案，支持计算和理论研究和教育，解决单个聚合物分子的构象相变对环境变量（如温度，压力，该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和许多基于聚合物的"智能"材料的功能性都直接与单个聚合物分子的潜在微观构象相关联。 许多智能或生物活性材料利用拴系到表面的聚合物链，而生物聚合物通常在非常拥挤的大分子环境中工作。在这种几何约束的环境中，聚合物可以表现出不同的行为，本研究的重点是聚合物约束的基本物理与材料设计的具体应用。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获得了本科合作者的重大贡献。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，（ii）研究单一聚合物的相变，特别是聚合物的全或无"折叠"，它可以在拥挤或几何限制的环境中为智能材料应用提供开/关开关;以及（iii）开发严格的分析工具，如配分函数零点和自由能景观，以研究聚合物体系中的相变和相变途径。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，态密度模拟方法和新的分析技术来理解单个大分子的行为。 这将有助于为功能性聚合物基和仿生材料开发合理的设计原则。 这项研究计划的目的是让最大的本科生参与到希拉姆学院的物理课程。 核心物理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。许多学生谁曾与PI在希拉姆，已经或将要在物理学，材料科学，工程学，或医学追求先进的研究。 PI旨在继续为学生提供成功的教育经验，并帮助招募更多代表性不足的学生进入科学领域。

NONTECHNICAL SUMMARYThis award made on a Research at an Undergraduate Institute (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 biological cells 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 a 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. Many students who have worked with the PI at Hiram, have, or will be, pursuing advanced study in physics, materials science, engineering, or medicine. The PI aims to continue to provide successful educational experiences for students, and to help recruit more under-represented students into the sciences.TECHNICAL SUMMARYThis award made on an Research at an Undergraduate Institution (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 linked to the underlying microscopic conformation of individual polymer molecules. Many smart or biologically active materials utilize polymer chains tethered to surfaces while biopolymers typically operate in very crowded macromolecular environments. In this geometrically constrained environment polymers can behave differently and a focus of this research is on the basic physics of polymer confinement with specific applications to materials design. This research continues and extends 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 to: (i) 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) study single-polymer phase transitions, in particular, polymer all-or-none "folding", which can provide an on/off switch in smart materials applications, in crowded or geometrically confined environments; and (iii) develop rigorous analysis tools such as partition function zeros and free energy landscapes to study phase transitions and transition pathways in polymer systems. This work will make use of both a 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 new analysis techniques. It will contribute to efforts to develop rational design principles for functional polymer-based and biomimetic materials. This research program has been designed to allow for maximum undergraduate student participation by dovetailing into the physics curriculum at Hiram College. Computation and simulation methods taught in the core physics 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. Many students who have worked with the PI at Hiram, have, or will be, pursuing advanced study in physics, materials science, engineering, or medicine. The PI aims to continue to provide successful educational experiences for students, and to help recruit more under-represented students into the sciences.