Dynamics of Polymers

该奖项支持聚合物物理学的理论和计算研究和教育。PI将研究（a）聚合物结晶，以及（B）DNA和其他聚合物分子通过蛋白质通道和纳米孔的易位。聚合物溶液和熔体的结晶是高分子科学中一个长期而有趣的研究课题。PI将使用模拟和理论对层状晶体的形状和尺寸及其动力学进行建模。研究的基本参数是（a）沿沿着链主链的扭转能和链刚度，（B）非键合原子之间的货车德瓦尔斯能和溶剂质量，（c）链长，（d）聚合物浓度，（e）温度，和（f）强度和流速。这些参数将在模拟形成的晶体的大小，形状和对称性，以及在不同条件下其生长前沿的细节中进行系统的探索。建立了聚合物结晶动力学的粗粒度模型。这些将包含在这些模拟中揭示的基本分子特征。这项工作的目的是了解聚合物分子在溶液中如何组织成晶体的早期阶段。拟议中的研究将超越劳里岑和霍夫曼以及萨德勒和吉尔默的模型。聚合物分子如何在物理化学作用下从一个位置转移到另一个位置也没有得到很好的理解，尽管生命的存在取决于聚合物的转移。研究将解决与基本理解单个DNA/RNA通过通道和纳米孔的易位相关的概念挑战。这些挑战包括：（a）聚合物的限制自由能如何受到相互作用的空腔及其连通性的影响，（B）聚合物如何由于局部自由能梯度和外部施加的场而在该自由能景观中移动，（c）流体动力学对限制中聚合物移动的作用，（d）聚合物主链与孔的方向性的取向耦合，（e）来自聚合物二级结构对移位的干扰，和（f）从限制中图案导向的控制释放β分子。这种理论和计算工作补充了实验研究，也可能与应用领域有关，例如聚合物加工，聚合物纳米材料的制造，分离技术，如色谱和电泳，生物学中的信号转导以及DNA和蛋白质的高速测序。该奖项还对各级教育产生了广泛影响。%该奖项支持聚合物物理学的理论和计算研究和教育。PI将研究（a）聚合物结晶，以及（B）DNA和其他聚合物分子通过蛋白质通道和纳米孔的易位。聚合物从溶液和熔体中的结晶是高分子科学中一个长期而有趣的研究课题。对聚合物链如何组织成分层结构的基本理解仍然是难以捉摸的。类似地，尽管生命的存在依赖于聚合物的迁移，但人们对聚合物分子如何在物理化学作用下从一个位置转移到另一个位置还没有很好的了解。PI旨在建立新的概念模型，并发现聚合物组织和运动的新规律。这种理论和计算工作补充了实验研究，也可能与应用领域有关，如聚合物加工，聚合物纳米材料的制造，分离技术，如色谱和电泳，生物学中的信号转导，以及DNA和蛋白质的高速测序。这一奖项也对各级教育产生了广泛的影响。

This award supports theoretical and computational research and education in polymer physics. The PI will investigate (a) polymer crystallization, and (b) translocation of DNA and other polymer molecules through protein channels and nanopores. Crystallization of polymers from solutions and melts is an intriguing and longstanding research problem in polymer science. The PI will model the shapes and sizes of lamellar crystals and their kinetics using simulation and theory. The basic parameters of the study are (a) torsional energy along chain backbone and chain stiffness, (b) van der Waals energy between nonbonded atoms and solvent quality, (c) chain length, (d) polymer concentration, (e) temperature, and (f) strength and rate of flow. These parameters will be systematically explored in simulations of the sizes, shapes and symmetries of formed crystals, and details of their growth fronts under different conditions. Coarse-grained models of kinetics of polymer crystallization will be built. These will incorporate the essential molecular features revealed in these simulations. An aim of this work is to understand the early stages of how polymer molecules organize into crystals in solution. The proposed research will go beyond the models of Lauritzen and Hoffmen, and of Sadler and Gilmer. How polymer molecules are transported from one location to another under physiochemically imposed fields is also not well understood, although the very existence of life depends on polymer translocation. Research will address conceptual challenges associated with a fundamental understanding of translocation of a single polyelectrolyte such as DNA/RNA through channels and nanopores. These challenges include: (a) how confinement free energy of a polymer is affected by interacting cavities and their connectivity, (b) how the polymer moves in this free energy landscape due to local free energy gradients and externally imposed fields, (c) role of hydrodynamics on polymer movement in confinement, (d) orientational coupling of the polymer backbone with the directionality of the pore, (e) interference from the secondary structures of the polymer on translocation, and (f) pattern-directed controlled release of polyelectrolyte molecules from confinement. This theoretical and computational work complements experimental investigations and may also be relevant to applied areas, such as polymer processing, fabrication of polymeric nanomaterials, separation techniques like chromatography and electrophoresis, signal transduction in biology, and high-speed sequencing of DNA and proteins. This award also has a broad impact on education at all levels.%%%This award supports theoretical and computational research and education in polymer physics. The PI will investigate (a) polymer crystallization, and (b) translocation of DNA and other polymer molecules through protein channels and nanopores. Crystallization of polymers from solutions and melts is a longstanding and intriguing research problem in polymer science. A fundamental understanding of how polymer chains organize into heirarchical structures remains elusive. Analogously, how polymer molecules are transported from one location to another under physiochemically imposed fields is not well understood, although the very existence of life depends on polymer translocation. The PI aims to build new conceptual models and discover new laws of polymer organization and motility. This theoretical and computational work complements experimental investigations and may also be relevant to applied areas such as polymer processing, fabrication of polymeric nanomaterials, separation techniques like chromatography and electrophoresis, signal transduction in biology, and high-speed sequencing of DNA and proteins. This award also has a broad impact on education at all levels.***