Poly(ethylene oxide) and Water: Simulations and Modeling of Solution Properties, Phase Behavior, Partitioning and Particle Interactions

0076306 smith本基金由化学学部理论化学和材料理论学科联合资助。聚环氧乙烷（PEO），也被称为聚乙二醇，用于多种水溶液应用，从减阻到药物输送。此外，PEO溶液已经得到了广泛的研究，它们本身具有基本的兴趣，同时也可以作为模型系统，以更好地理解水性聚合物溶液。实验和建模研究对PEO解决方案的行为产生了有价值的见解。然而，这些溶液的许多最有趣的特性，如构象、疏水相互作用、相行为、盐的影响以及聚合物与颗粒和蛋白质的相互作用，对它们的广泛应用仍知之甚少。该研究的主要目标是通过对PEO溶液的协调模拟和建模研究来提高对水性聚合物溶液行为的理解，开发和传播进行这些研究所需的计算算法和工具，并使本科生熟悉分子建模的力量和效用。原子分子动力学模拟研究将用于研究PEO水溶液的构象、结构、热力学和动力学性质。将进行额外的模拟，以了解PEO溶液的相行为，包括分子量和压力的影响以及聚合物构象、水结构和醚-水氢键的作用。最后，将进行PEO溶液与模型纳米颗粒和蛋白质相互作用的模拟研究，旨在更好地理解聚合物介导的颗粒之间的耗竭吸引力，以及竞争性水合作用和疏水性聚合物-颗粒相互作用的作用。实现这些科学目标需要在广泛的长度尺度上寻址解决方案属性的能力。将创建一个力场开发工具包，通过精确的经典原子势函数参数化，将电子结构水平与原子水平联系起来。反过来，PEO溶液的原子分子动力学模拟的详细结果将作为聚合物溶液和聚合物与颗粒相互作用的液态理论模型的输入，有可能扩展原子研究的长度尺度，并允许对参数空间的研究远远超出分子动力学模拟直接获得的范围。这些研究除了提高对PEO解决方案的理解所带来的好处之外，还具有重要的影响。这些努力将大大增加对合成和生物水溶液以及一般聚合物溶液行为的总体理解，特别是在交叉浓度制度和缺乏模拟研究的较高浓度下。为提出的模拟开发的计算工具和算法，如力场开发工具包和确定聚合物溶液中自由能和相平衡的方法，将对模拟界广泛有益。目前用于研究生教学以及研究生和本科生水平研究的分子动力学模拟工具将发展成为本科课程的工具，并将包括材料模拟和性质预测模块，旨在为本科生提供计算材料科学的实践经验。本基金由化学学部的理论化学和材料理论项目联合资助。聚环氧乙烷（PEO），也被称为聚乙二醇，用于多种水溶液应用，从减阻到药物输送。此外，PEO溶液已经得到了广泛的研究，它们本身具有基本的兴趣，同时也可以作为模型系统，以更好地理解水性聚合物溶液。实验和建模研究对PEO解决方案的行为产生了有价值的见解。然而，这些溶液的许多最有趣的特性，如构象、疏水相互作用、相行为、盐的影响以及聚合物与颗粒和蛋白质的相互作用，对它们的广泛应用仍知之甚少。该研究的主要目标是通过对PEO溶液的协调模拟和建模研究来提高对水性聚合物溶液行为的理解，开发和传播进行这些研究所需的计算算法和工具，并使本科生熟悉分子建模的力量和效用。* * *

0076306SmithThis grant is funded jointly by the Theoretical Chemistry and Materials Theory Programs in the Divisions of Chemistry and Materials Research respectively. Poly(ethylene oxide) (PEO), also referred to as poly(ethylene glycol), is used in a multitude of aqueous solution applications ranging from drag reduction to drug delivery. In addition, PEO solutions have been widely studied, being themselves of fundamental interest as well as serving as model systems in efforts to better understand aqueous polymer solutions. Experimental and modeling studies have resulted in valuable insight into the behavior of PEO solutions. However, many of the most interesting characteristics of these solutions responsible for their broad scope of applications, such as conformations, hydrophobic interactions, phase behavior, the influence of salts, and the interactions of the polymer with particles and proteins, remain at best poorly understood.The principal goals of the research are to gain improved understanding of the behavior of aqueous polymer solutions through coordinated simulation and modeling studies of PEO solutions, to develop and disseminate the computational algorithms and tools required to carry out these studies, and to familiarize undergraduate students students with the power and utility of molecular modeling. Atomistic molecular dynamics simulation studies will be carried out in order to investigate the conformational, structural, thermodynamics and dynamic properties of aqueous PEO solutions. Additional simulations aimed specifically at understanding the phase behavior of PEO solutions, including the influence of molecular weight and pressure as well as the role of polymer conformations, water structure, and ether-water hydrogen bonding, will be performed. Finally, simulation studies of the interactions of PEO solutions with model nanoparticles and proteins will be carried out, aimed at gaining a better understanding of polymer mediated depletion attraction between particles as well as the roles of competitive hydration and hydrophobic polymer-particle interactions. Acheiving these scientific goals requires the capability of addressing solution properties over a wide range of length scales. A force field development toolkit will be created to link the electronic structure level to the atomistic level through parametrization of accurate classical atomistic potential functions. In turn, the detailed results of atomistic molecular dynamics simulations of PEO solutions will serve as input into liquid state theory models for polymer solutions and interactions of polymers with particles, potentially extending the length scale of the atomistic studies as well as allowing investigation of parameter space well beyond that directly accessible by molecular dynamics simulations.These studies have important ramifications beyond the benefits provided by an improved understanding of PEO solutions. These efforts will add significantly to the overall understanding of the behavior of aqueous solutions, both synthetic and biological, as well as that of polymer solutions in general, particularly in crossover concentration regimes and at higher concentrations where there is a paucity of simulation studies. The computational tools and algorithms developed for the proposed simulations, such as the force field development toolkit and methods for determining free energies and phase equilibrium in polymer solutions, will be widely beneficial to the simulation community. Molecular dynamics simulations tools, currently used for graduate teaching as well as graduate and undergraduate level research, will be developed into tools for undergraduate coursework and will include materials simulation and property prediction modules designed to give undergraduate students hands-on experience with computational materials science.%%% This grant is funded jointly by the Theoretical Chemistry and Materials Theory Programs in the Divisions of Chemistry and Materials Research respectively. Poly(ethylene oxide) (PEO), also referred to as poly(ethylene glycol), is used in a multitude of aqueous solution applications ranging from drag reduction to drug delivery. In addition, PEO solutions have been widely studied, being themselves of fundamental interest as well as serving as model systems in efforts to better understand aqueous polymer solutions. Experimental and modeling studies have resulted in valuable insight into the behavior of PEO solutions. However, many of the most interesting characteristics of these solutions responsible for their broad scope of applications, such as conformations, hydrophobic interactions, phase behavior, the influence of salts, and the interactions of the polymer with particles and proteins, remain at best poorly understood.The principal goals of the research are to gain improved understanding of the behavior of aqueous polymer solutions through coordinated simulation and modeling studies of PEO solutions, to develop and disseminate the computational algorithms and tools required to carry out these studies, and to familiarize undergraduate students students with the power and utility of molecular modeling. ***