Fundamental Studies on Transport of Ions and Large Penetrants Through Structured Polymer Matrices

技术概述该奖项支持具有增强的机械和电化学性能的聚合物膜的理论研究和教育。最近旨在开发具有这些性能的聚合物膜的实验探索了各种策略，包括导电均聚物的交联化，使用无机填料来制备聚合物纳米复合膜，以及使用机械强度较强的嵌段与导电相互补的两嵌段共聚物。虽然通过这种方法可以提高力学性能，但在传输特性与表征这些改性聚合物膜的物理化学参数之间的依赖关系方面也注意到了有趣的观察结果。为了了解传输特性，PI计划研究两大类系统中涉及离子和大分子渗透剂的扩散过程的物理：(I)含有纳米颗粒填料的聚合物膜：PI旨在使用一种结合原子水平分子动力学和粗粒动力学蒙特卡罗方法的混合模拟方法来探索聚合物纳米复合膜导电性行为的机理根源。PI将使用这种模拟方法来研究填料对离子运动、络合和聚合物运动的影响，并揭示聚合物-填料相互作用和颗粒浓度的作用；(Ii)纳米结构/自组装嵌段共聚物膜：PI计划使用粗粒键涨落蒙特卡罗模拟方法来探索嵌段共聚物膜导电和传输性能行为的机理基础。特别是，PI建议在离子的非带电、选择性溶剂表示的背景下使用模拟来揭示离子运动、聚合物动力学、自组装形态和组成波动对膜的宏观传输特性的相互作用。这项研究有望更好地理解离子和大分子在这种结构和不均匀的聚合物基质中渗透扩散的机制。在这个项目的过程中，将在使用原子模拟和粗粒度模拟研究离子和渗透传输的计算方法和理论模型方面取得进展。由此产生的方法也可能应用于燃料电池和净水膜。教育的更广泛影响与研究目标相结合，包括本科生研究人员参与这一项目的机会，目的是将社区学院的学生包括在内。还将组织一个国际研讨会，专门讨论软物质系统的平衡和动力学方面的粗粒化的基本方面。非技术总结该奖项支持有助于开发改进的电池和燃料电池的理论研究和教育。在寻求清洁和可持续能源的过程中，电池和燃料电池等电化学设备最近变得流行起来。当今的许多电池都涉及液体电解液的存在，这种电解液用来在带正电的终端和带负电的终端之间传导离子。然而，这种液体成分的存在会导致潜在的安全问题。为了提高安全性，研究人员寻求开发导电介质，即电解液，这种介质不可燃，但仍能确保电池的有效运行。在这种背景下，塑料已成为潜在的候选者。然而，设计足够坚固并具有使电池有效运行的性能的塑料材料仍然是一个挑战。PI将开发基于计算机的工具来研究已被证明具有电池所需性能的新型聚合物材料。基于计算机的工具将提供询问聚合物材料的操作的手段，从而为设计具有更好和改进的性能的新材料提供方向。该项目开发的工具可用于研究其他可再生能源选择，如燃料电池和净水膜的运行。这个项目将为本科生和研究生创造新的研究机会，学习新出现的材料类别，从而提出改进其性能的策略。此外，还将设计新的课程和演示模块，以教育学生和公众了解燃料电池、电池和太阳能电池等设备的基本原理。

Technical SummaryThis award supports theoretical research and education on polymeric membranes possessing both enhanced mechanical and electrochemical properties. Recent experiments aiming to develop polymeric membranes with these properties explore a variety of strategies, including cross-linking of the conductive homopolymers, use of inorganic fillers to create polymer nanocomposite membranes, and using diblock copolymers in which a mechanically strong block complements the conducting phase. While mechanical properties can be enhanced by such means, intriguing observations have also been noted in the dependencies of transport properties upon the physicochemical parameters that characterize these modified polymer membranes.Motivated to understand the transport properties, the PI plans to study the physics of diffusion processes involving ions and large molecule penetrants in two broad classes of systems: (i) Polymer membranes containing nanoparticulate fillers: the PI aims to use a hybrid simulation approach combining atomistic level molecular dynamics with a coarse-grained kinetic Monte Carlo approach to probe the mechanistic origins of the behavior of the conductivity of polymer nanocomposite membranes. The PI will use such a simulation approach to interrogate the filler-induced modifications to the ion motion, complexation and polymer motion, and to unravel the roles of the polymer-filler interactions and particle concentrations; (ii) Nanostructured/self-assembled block copolymer membranes: The PI plans to use a coarse-grained bond fluctuation Monte Carlo simulation approach to probe the mechanistic underpinnings of the behavior of the conductivity and transport properties of block copolymer membranes. In particular, the PI proposes to use simulations within the context of a non-charged, selective solvent representation of the ion to unravel the interplay between ion motion, polymer dynamics, the morphology of self-assembly, and composition fluctuations upon the macroscopic transport properties of the membrane. This research is expected to result in a better understanding of the mechanisms underlying ion and large molecule penetrant diffusion in such structured and inhomogeneous polymeric matrices. Advances in computational approaches and theoretical models for studying ionic and penetrant transport using atomistic and coarse-grained simulations will be made in the course of this project. Resulting methods may also have applications to fuel cells and water purification membranes.The educational broader impacts are integrated with research aims, and include opportunities for undergraduate researchers to participate in this project with an aim to include students from community colleges. An international workshop devoted to fundamental aspects of coarse-graining the equilibrium and dynamical aspects of soft-matter systems will also be organized.Non-Technical SummaryThis award supports theoretical research and education that can contribute to developing improved batteries and fuel cells. Electrochemical devices such as batteries and fuel cells have recently become popular in the quest for clean and sustainable energy sources. Many present-day batteries involve the presence of a liquid electrolyte which serves to conduct ions between the positively charged terminal and the negatively charged terminal. However, the presence of this liquid component leads to potential safety issues. To enhance safety, researchers seek to develop conducting media, electrolytes, which are non-flammable but still ensure efficient operation of the batteries. In this context, plastics have emerged as potential candidates. However, it remains a challenge to design plastic materials that are strong enough and have properties that lead to efficient battery operation.The PI will develop computer-based tools to investigate new classes of polymeric materials which have been demonstrated to possess properties desirable for batteries. The computer-based tools will provide means to interrogate the operation of the polymeric materials and thereby suggest directions for designing new materials with better and improved properties. The tools developed in this project are can be adapted to study other renewable energy options such as fuel cells and the operation of water purification membranes. This project will create new research opportunities for both undergraduate and graduate students to study the newly emerging classes of materials and thereby suggest strategies for improving their properties. Moreover, new courses and demonstration modules will be designed to educate students and the public on the principles underlying devices such as fuel cells, batteries, and solar cells.