Molecular Motions in Flowing Semi-dilute Polymer Solutions

流动半稀聚合物溶液中的分子运动

• 批准号: 1803757
• 负责人: Charles Sing
• 金额: $ 29.08万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1803757&HistoricalAwards=false
• 关键词: Molecular; Motions; Flowing; Semi; dilute

Polymers are large, chain-like molecules that are the building blocks of both industrially-relevant products (i.e. plastics, coatings, and fibers) and state-of-the-art advanced materials for devices such as flexible photovoltaics and displays. For many of these applications, the polymer must be processed with an eye towards its final properties; for example, in order to create strong fibers, a "drawing" process is used to align polymer chains. Similarly, coating flows can control molecular packing (and thus charge transport) in semiconducting polymers. For both situations, polymers are manipulated in a liquid solution by applying strong flows. However, it remains challenging to understand how exactly flow influences molecular motions. This challenge arises because long polymer chains interpenetrate, so that any given molecule interacts with many others both directly and via solvent flows. The proposed research will use new computational algorithms to understand the connection between polymer motions, molecular-level fluid dynamics, and applied flows. This understanding will serve as the foundation for molecular control in polymer solution processing, by showing how concentration and strong flows can be used to tune molecular structure and correspondingly material properties. This project will also serve to train the next generation of scientists, through the interdisciplinary training and mentorship of students. In addition, this project will involve the development of outreach events that incorporate interactive experimental/computer simulation into hands-on activities designed to promote the participation of underrepresented students in STEM fields.Polymer solutions are typically processed in the ?semi-dilute? regime, where individual coils overlap significantly. Semidilute solutions are characterized by significant solvent-mediated hydrodynamic interactions (HI) and topological ?hooking?. Current theory is capable of capturing equilibrium properties (relaxation time, molecular structure) but has not been extended to flowing solutions. A new conformational-averaging procedure is capable of efficiently simulating large systems, enabling exploration of how HI and chain topology affect highly out-of-equilibrium polymer conformations in flow. This proposal will address two aims: (i) Understand how concentration and hydrodynamic interactions affect chain dynamics in flowing semi-dilute polymer solutions and (ii) capture how non-linear polymer architectures and shear flows lead to molecular ?hooking?. The first aim will characterize the distortion of hydrodynamic screening by strong flows and extend equilibrium scaling concepts to out-of-equilibrium systems. The second aim will use topological invariants to characterize hooking interactions, and how they affect the distributions of molecular conformations. The proposed work will thus provide insight important for flow-controlled solution processing of polymers, ranging from flow coating to inkjet or 3D printing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

聚合物是大的链状分子，是工业相关产品（即塑料，涂料和纤维）和最先进的先进材料（如柔性光致发光和显示器）的组成部分。对于这些应用中的许多应用，聚合物的加工必须着眼于其最终性能;例如，为了产生强纤维，使用“拉伸”工艺来排列聚合物链。类似地，涂层流可以控制半导体聚合物中的分子堆积（从而控制电荷传输）。对于这两种情况，聚合物在液体溶液中通过施加强流动来操纵。 然而，它仍然具有挑战性，以了解如何确切地流动影响分子运动。这一挑战的出现是因为长的聚合物链相互渗透，使得任何给定的分子与许多其他分子直接或通过溶剂流动相互作用。拟议的研究将使用新的计算算法来理解聚合物运动，分子水平流体动力学和应用流之间的联系。这种理解将作为聚合物溶液加工中分子控制的基础，通过展示浓度和强流动如何用于调节分子结构和相应的材料特性。该项目还将通过对学生进行跨学科培训和指导，培养下一代科学家。 此外，该项目将涉及外展活动的发展，将交互式实验/计算机模拟纳入旨在促进STEM领域代表性不足的学生参与的实践活动。半稀释？制度，其中个别线圈重叠显着。半稀释液的解决方案的特点是显着的溶剂介导的流体动力学相互作用（HI）和拓扑？妓女？目前的理论能够捕获平衡性质（弛豫时间，分子结构），但尚未扩展到流动的解决方案。一种新的构象平均程序能够有效地模拟大型系统，使探索HI和链拓扑结构如何影响高度不平衡的聚合物构象的流动。这项建议将解决两个目标：（一）了解浓度和流体动力学相互作用如何影响链动力学流动的半稀释聚合物溶液和（ii）捕获如何非线性聚合物结构和剪切流导致分子？妓女？第一个目标是描述强流引起的水动力屏蔽畸变，并将平衡标度概念扩展到非平衡系统。第二个目标将使用拓扑不变量来表征钩相互作用，以及它们如何影响分子构象的分布。因此，拟议的工作将为聚合物的流动控制溶液加工提供重要的见解，从流涂到喷墨或3D打印。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Dynamics and rheology of ring-linear blend semidilute solutions in extensional flow. Part I: Modeling and molecular simulations

• DOI: 10.1122/8.0000221
• 发表时间: 2020-11
• 期刊: Journal of Rheology
• 影响因子: 3.3
• 作者: Charles D. Young;Yuecheng Zhou;Charles M. Schroeder;C. Sing

Nonmonotonic dependence of comb polymer relaxation on branch density in semidilute solutions of linear polymers

• DOI: 10.1103/physrevfluids.5.121301
• 发表时间: 2020-12-17
• 期刊: PHYSICAL REVIEW FLUIDS
• 影响因子: 2.7
• 作者: Patel, Shivani F.;Young, Charles D.;Schroeder, Charles M.
• 通讯作者: Schroeder, Charles M.

Conformationally averaged iterative Brownian dynamics simulations of semidilute polymer solutions

半稀聚合物溶液的构象平均迭代布朗动力学模拟

• DOI: 10.1063/1.5041453
• 发表时间: 2018
• 期刊: The Journal of Chemical Physics
• 作者: Young, Charles D.;Marvin, Michael;Sing, Charles E.
• 通讯作者: Sing, Charles E.

Dynamics and rheology of ring-linear blend semidilute solutions in extensional flow: Single molecule experiments

拉伸流中环状线性混合半稀溶液的动力学和流变学：单分子实验

• DOI: 10.1122/8.0000219
• 发表时间: 2021
• 期刊: Journal of Rheology
• 影响因子: 3.3
• 作者: Zhou, Yuecheng;Young, Charles D.;Lee, Megan;Banik, Sourya;Kong, Dejie;McKenna, Gregory B.;Robertson-Anderson, Rae M.;Sing, Charles E.;Schroeder, Charles M.
• 通讯作者: Schroeder, Charles M.