Mesoscale modeling of self-assembly and transport in polymer electrolyte membranes

技术摘要该奖项支持理论和计算研究及教育，以开发模拟方法来模拟聚电解质膜的结构和传输特性。聚电膜是固体聚合物电解质燃料电池的关键和最昂贵的组件之一，固体聚合物电解质燃料电池是一种很有前途的利用氢和氧生产能源的技术。更好地理解纳米结构形成和聚电解质膜电导率的基本机制可能会导致现有固体聚合物电解质燃料电池的改进。聚电解质膜的分离和传输特性由其自组装纳米结构决定：水合后，膜在介观尺度上分离成亲水性和疏水性亚相。该项目负责人旨在开发一种介观模拟方法，用于基于耗散粒子动力学技术的聚电解质膜自组装和质子电导率的研究，该技术具有从头算和原子分子动力学模拟确定的粗粒度相互作用参数。新方法包括引入沿自组装聚电解质膜亲水亚相传输质子的介观模型。新方法将根据现有的实验数据以及离聚物碎片和传统 Nafion 膜的早期模拟进行测试。 该模拟方法将能够直接计算研究耦合聚电解质膜中的分离形态和质子传输。该 PI 旨在促进对自组装、吸水性和渗透性以及质子传导性的物理化学机制的基本理解。将开发的模拟方法和将建立的结构-性能关系有可能产生重大影响，并加速用于燃料电池选择性渗透膜的新型聚电解质的搜索，从而有助于开发用于可持续氢基能源技术的新型材料。该奖项支持理论和计算纳米材料科学与工程方面的研究生、本科生和博士后培训。少数族裔本科生将通过罗格斯大学特殊培训项目招收。将创建一个专门的网页，用于提供用于教育目的的项目报告和演示。计算机代码以及指导性案例研究示例将发布在该网页上，免费分发给科学界。开发的模拟方法和案例研究系统将纳入新的研究生课程“纳米级热力学和传输”。非技术摘要。该奖项支持理论研究和教育，以开发用于模拟聚电解质膜的结构和传输特性的计算方法。 聚电解质膜是聚合物交换膜燃料电池的关键和最昂贵的组件之一，是一种从氢和氧中提取电能的有前途的技术。聚电解质膜由疏水性和亲水性片段组成的复杂链分子组成。为了在燃料电池中发挥作用，聚电解质膜将两个电极（阳极和阴极）分开，并且只允许氢离子或质子通过，而留下电子。由质子和电子组成的氢原子在阳极分裂，释放出电子，通过电路（例如电动汽车中的发动机）流向阴极。质子穿过膜到达阴极，在阴极与穿过电路的电子和氧原子重新结合，形成水，从燃料电池中排出。聚电解质膜仅传导质子的能力对于燃料电池的运行至关重要。在工作条件下，聚电解质膜表现出一种分子自组装或重组——疏水片段形成质子传导通道的三维网络。膜传导质子的能力取决于自组装过程产生的膜的化学成分和结构的具体情况。 PI将开发一种新型计算机模拟技术，以确定聚电解质膜的化学成分、工作条件下的结构及其传导质子的能力之间的关系，旨在确定新型燃料电池膜的最佳设计。这项研究的结果可能会产生跨学科的影响，因为它解决了目前尚未解决的与合成和生物聚电解质材料中的自组装和电荷传导相关的热门问题。研究过程中开发的计算机建模工具可以进行调整和修改，以模拟和优化其他材料，并有可能应用于涉及 DNA、蛋白质和生理膜的生物医学系统和生物医学技术。这项研究有助于开发可持续能源。该奖项支持理论和计算纳米材料科学与工程方面的研究生、本科生和博士后培训。少数族裔本科生将通过罗格斯大学特殊培训项目招收。将创建一个专门的网页，用于提供用于教育目的的项目报告和演示。计算机代码以及指导性案例研究示例将发布在该网页上，免费分发给科学界。开发的模拟方法和案例研究系统将纳入新的研究生课程“纳米热力学和传输”。

TECHNICAL SUMMARYThis award supports theoretical and computational research and education to develop simulation methods to model structural and transport properties of polyelectrolyte membranes. Polyelectric membranes are one of the critical and most expensive components of the solid polymer electrolyte fuel cells, a promising technology for energy production from hydrogen and oxygen. A better understanding of the basic mechanisms of nanostructure formation and conductivity of polyelectrolyte membranes could lead to improvement of currently available solid polymer electrolyte fuel cells. Separation and transport properties of polyelectrolyte membranes are determined by their self-assembled nanostructure: upon hydration, the membrane segregates into hydrophilic and hydrophobic subphases on the mesoscopic scale. The PI aims to develop a mesoscale simulation method for studies of polyelectrolyte membranes self-assembly and proton conductivity based on the dissipative particle dynamics technique with coarse-grained interaction parameters determined from ab initio and atomistic molecular dynamics simulations. The new method includes the introduction of a mesoscopic model of proton transport along the hydrophilic subphase of the self-assembled polyelectrolyte membranes. The new method will be tested against available experimental data and earlier simulations of ionomer fragments and traditional Nafion membranes. The simulation method will enable direct computational investigation of segregated morphology and proton transport in coupled polyelectrolyte membranes. The PI aims to advance fundamental understanding of the physico-chemical mechanisms of self-assembly, water sorption and permeability, and proton conductivity. The simulation methods that will be developed and structure-property relationships that will be established have the potential to have significant impact and accelerate the search of new polyelectrolytes for permselective membranes for fuel cells, thus contributing to the effort to develop novel materials for sustainable hydrogen-based energy technologies. This award supports graduate, undergraduate, and postdoctoral training in theoretical and computational nanomaterials science and engineering. Minority undergraduate students will be recruited through the Rutgers special training programs. A dedicated webpage will be created for making project reports and presentations available for educational purposes. Computor codes together with instructive case study examples will be posted on this webpage for free distribution to the scientific community. Simulation methods developed and case-study systems will be included into a new graduate course on "Nanoscale Thermodynamics and Transport."NONTECHNICAL SUMMARY. This award supports theoretical research and education to develop computational methods for modeling structural and transport properties of polyelectrolyte membranes. Polyelectrolyte membranes are one of the critical and most expensive components of polymer exchange membrane fuel cells, a promising technology for the extraction of electric energy from hydrogen and oxygen. Polyelectrolyte membranes are made of complex chain molecules composed of hydrophobic and hydrophilic fragments. To function in a fuel cell, a polyelectrolyte membrane separates the two electrodes, the anode and the cathode, and allows only hydrogen ions or protons to pass through it leaving electrons behind. Hydrogen atoms, composed of a proton and an electron, are split at the anode liberating the electron that flows to the cathode through an electric circuit, for example the motor in an electric car. The proton flows through membrane to the cathode where it is reunited with the electron that has traveled trhough the circuit and oxygen atoms to form water which is expelled from the fuel cell. The ability of the polyelectrolyte membrane to conduct only protons is crucial for the operation of the fuel cell. Under working conditions, polyelectrolyte membranes exhibit a kind of self-assembly or restructuing of its molecules - the hydrophobic fragments form a three dimensional network of proton-conducting channels. The ability of the membrane to conduct protons depends of the specifics of the chemical composition and structure of the membrane that results from the self-assembly process. The PI will develop a novel computer simulation technique to determine the relationships among the chemical composition of the polyelectrolyte membrane, its structure under working conditions, and its ability to conduct protons, with the aim of determining optimal designs for novel fuel cell membranes. The results of this research could have impact across disciplines, since it addresses currently unresolved topical problems related to self-assembly and charge conduction in synthetic and biological polyelectrolyte materials. Computer modeling tools developed in the course of the research can be adapted and modified for simulation and optimization of other materials with potential to have application to biomedical systems and biomedical technologies involving DNA, proteins, and physiological membranes. This research contributes to the effort to develop sustainable energy sources.This award supports graduate, undergraduate, and postdoctoral training in theoretical and computational nanomaterials science and engineering. Minority undergraduate students will be recruited through the Rutgers special training programs. A dedicated webpage will be created for making project reports and presentations available for educational purposes. Computor codes together with instructive case study examples will be posted on this webpage for free distribution to the scientific community. Simulation methods developed and case-study systems will be included into a new graduate course on "Nanoscale Thermodynamics and Transport."