Systematic Control of the Crystalline Morphology in Perfluorosulfonate Ionomer Membranes

CBET-0756439Moore这一基本项目旨在填补我们对现代燃料电池膜中主干链有序填充所产生的聚合物晶体的形式和功能的理解中的一个关键空白。虽然我们已经了解了很多关于功能聚合物中质子传导离子域的组织，例如全氟磺酸离聚体(PFSI)Nafion，但值得注意的是，我们对这些材料中微晶的详细结构和形成，或者这些有序特征相对于离子域邻近的空间排列知之甚少。与绝大多数这些具有重要技术意义的聚合物的形态研究不同，这个项目将专注于另一种聚合物。这些膜的重要形态特征，即结晶成分的关键意义。该项目的实验方法将包括(1)开发和改进系统地控制PFSI中结晶度和结晶度的方法，(2)结晶成分的结构表征，以及(3)分析结晶顺序对燃料电池相关性能的影响。有了量身定制的膜工艺提供的受控范围的结晶度，以及目前推出的具有较短功能侧链结构的新型高结晶度PFSI，我们将能够最终分离出这一属性在膜性能/耐用性方面的具体贡献，并允许全面了解导致质子交换膜燃料电池(PEMFC)应用中高效能量转换的形态因素。这项研究将对用于PFSI膜的传统工艺参数的根本修改产生影响，这些参数侧重于开发更有序的晶区，并刺激多学科的膜设计和制造方法。从社会影响的角度来看，预计这一特定领域的基础研究将能够在对环境影响较小的情况下实现更高效、更稳健和更可持续的能源转换。参与这个项目的学生将接触到最先进的形态表征方法、膜制造的工程方面以及燃料电池科学的现代技术。在这项工作的过程中开发的教育模块将被纳入弗吉尼亚理工大学科学和工程项目的扩展能源课程。

CBET-0756439MooreThis fundamental project is aimed at filling a critical void in our understanding of the form and function of polymeric crystals produced by the ordered packing of backbone chains in modern fuel cell membranes. While we have learned a great deal about the organization of the proton-conducting ionic domains in functional polymers such as the perfluorosulfonate ionomer (PFSI) Nafion, it is remarkable that we know very little about the detailed structure and formation of the crystallites in these materials or the spatial arrangement of these ordered features with respect to the proximity of the ionic domains. In contrast to the vast majority of morphological studies of these technologically important polymers, this project will be focused on the ?other? important morphological feature in these membranes, namely the critical significance of the crystalline component. The experimental approach in this project will involve (1) development and refinement of methods to systematically control the degree and organization of crystallinity in PFSIs, (2) structural characterization of the crystalline component, and (3) analysis of the fuel cell relevant properties impacted by the crystalline order. With a controlled range of crystallinities provided by tailored membrane processing and new, highly crystalline PFSIs currently available with shorter functional sidechain structures, we will be able to finally isolate the specific contributions of this attribute in membrane performance/durability and allow a comprehensive understanding of the morphological factors that lead to efficient energy conversion in proton exchange membrane fuel cell (PEMFC) applications. This research will impact fundamental modifications to the conventional processing parameters used for PFSI membranes that focus on the development of more ordered crystalline domains, and stimulate a multi-disciplinary approach to membrane design and fabrication. From a societal impact perspective, it is anticipated that fundamental research in this specific area will enable a more efficient, robust, and sustainable energy conversion with low environmental impact. Students involved in this project will be exposed to state-of-the-art methods of morphological characterization, engineering aspects of membrane fabrication, and the modern technology of fuel cell science. Educational modules developed in the course of this work will be incorporated in the expanding energy curriculum of the Science and Engineering programs at Virginia Tech.