Structure and Dynamics of Soft Matter

有了这笔发现基金，我将研究离子导电聚合物的形态，长期目标是改善用于燃料电池的聚合物电解质膜(PEM)的材料性能。质子交换膜良好的质子导电性取决于聚合物的形态和离子的纳米结构。控制这种形态对于设计高性能的膜是必不可少的。这些实验将有助于为这些应用优化聚合物设计所需的基本理解，并最终帮助我们过渡到低碳社会。*这些研究将解决PEM研究中当前的挑战：通过开发坚固的碳氢化合物离聚体来减少对氟基聚合物的重视，延长聚合物的寿命，并提高耐久性。其中一个重点将是一系列碳氢化合物、质子导电聚合物，旨在提供氟系统的替代方案。这种材料是一种随机共聚物，但早期的研究表明，在纳米尺度上存在一些相分离；我们将研究其形态，以确定相的性质，并为下一代这些聚合物提供信息。我和我的研究小组还将研究一种新的碳氢化合物基阴离子导电随机共聚物，旨在用于碱性燃料电池，因为碱性环境允许使用更便宜的催化剂。我们最近的研究没有发现离子聚集的证据，而是表明水在亚纳米尺度上分布；我们将阐明导电机制。最后，这项研究将有助于通过研究Nafion的降解来了解聚合物的寿命，Nafion是燃料电池应用中最常用的聚合物。特别是，我们将研究在标准降解测试中形态如何变化。*我们使用的主要实验方法是基于材料的辐射散射。我的研究小组现在可以通过我实验室的光散射仪器(小角和经典的长度尺度，从10微米到20纳米的长度尺度)和最近安装在西蒙·弗雷泽大学材料设施的小角X射线散射仪(长度尺度从20纳米到0.2纳米)获得各种长度尺度。我们还使用中子散射来提供补充信息。这些工具使我们能够研究广泛的行为：聚合物分子的聚集、微相分离、离子聚集、聚合物主链有序性和单体水平的有序性。最近，我们已经成功地使用分子动力学模拟来补充我们在最小长度尺度上的测量，并计划继续开发这一能力。

With this Discovery Grant, I will study the morphology of ion-conducting polymers, with the long-term goal of improving material properties of polymer electrolyte membranes (PEMs) for fuel-cell applications. Good proton conductivity in PEMs depends on polymer morphology and ionic nanostructure. Controlling this morphology is essential to the design of high-performance membranes. These experiments will contribute to the fundamental understanding necessary to optimize polymer design for these applications, and ultimately aid our transition to a low-carbon society. ******These studies will address current challenges in PEM research: to reduce emphasis on fluorine-based polymers through development of robust hydrocarbon-based ionomers, to improve polymer lifetime, and to improve durability. One focus will be a series of hydrocarbon-based, proton-conducting polymers designed to offer an alternative to fluorine-based systems. This material is a random copolymer but early studies show some phase separation at nm length scales; we will study the morphology to determine the nature of the phases and inform the next generation of these polymers. My research group and I will also study a new hydrocarbon-based, anion-conducting random copolymer, designed for use in alkaline fuel cells where the alkaline environment allows for the use of much cheaper catalysts. Our recent studies show no evidence of ion-clustering and indicate that water is distributed at sub-nm length scales; we will elucidate conductivity mechanisms. Finally, this research will contribute to understanding polymer lifespans through studies of degradation of Nafion, the polymer most commonly used in fuel cell applications. In particular, we will study how the morphology changes during standard degradation tests.******The main experimental methods that we use are based on scattering of radiation from materials. My research group now has access to a wide range of length scales through light-scattering instruments in my lab (small-angle and classic, length scales from 10 microns to 20 nm) and a recently installed small-angle X-ray scattering instrument in Simon Fraser University's materials facility (length scales from 20 nm to 0.2 nm). We also use neutron scattering to provide complementary information. These tools allow us to study a wide range of behaviour: aggregation of polymer molecules, micro-phase separation, ion-clustering, polymer backbone ordering, and order at the monomer level. Recently, we have successfully used molecular dynamics simulations to complement our measurements at the smallest length scales and plan to continue to develop this capability.