Design and Synthesis of Robust Cationic Polymers for Stable and Efficient Anion-Exchange Membranes

卡内基梅隆大学的Kevin Noonan和Tomasz Koalewski教授在化学系高分子、超分子和纳米化学(MSN)计划的支持下，设计和制备了用作离子交换膜的新型带电聚合物。这些膜夹在燃料电池的负极和正极之间，被认为是这些能量转换装置的关键部件。各种与消费相关的产品依赖于燃料电池来产生清洁能源。采用适当的控制聚合技术合成了新型阳离子(带正电)聚合物膜。在燃料电池运行条件下，对它们的化学、电化学和机械稳定性进行了评估。这项工作的主要目标之一是制造能够承受燃料电池装置恶劣化学环境的耐用薄膜。如果成功，使用这些新合成的聚合物膜的燃料电池将不再依赖贵金属发电，这代表着显著的经济优势。来自不同背景的学生接受了培训，并参与了这个项目。一个带有教育材料和演示的“燃料电池项目”正在开发中。该项目在网上提供，用于教育初中生有关可再生能源生命周期的知识。在这个项目中，PI正在探索阳离子聚合物在氢氧离子存在下的化学和电化学稳定性。所获得的信息被用来建造用于燃料电池中离子传输的坚固膜。虽然质子在酸性条件下的传输已被证实，但在热应力和电化学应力下，氢氧化物在固体聚合物电解质中的传输仍然是一个巨大的挑战。开发用于穿梭这些苛性阴离子的下一代坚固、持久和惰性的阳离子材料需要合成和表征相结合的方法。可控聚合技术是制造聚合物材料的关键。用一系列表征技术对其结构、稳定性和形貌进行了评价。具体地说，用X射线散射、原子力显微镜、传输/器件测量和计算化学来探测这些膜的性质。通过合成定义明确的聚合物和嵌段共聚物来定制运输和机械性能。这些材料被用来建立离子传输和新型离聚体形态之间的关系。这项工作为后续的阴离子传输优化材料设计提供了基础。如果成功，该项目将为不需要贵金属的碱性燃料电池生产稳定高效的阴离子交换膜(AEMS)。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Professors Kevin Noonan and Tomasz Kowalewski of Carnegie-Mellon University are supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Division of Chemistry to design and prepare new charged polymers that function as ion-exchange membranes. These membranes are sandwiched between the negative and positive compartments of fuel cells and are considered a key component of these energy conversion devices. A variety of consumer related products rely on fuel cells for clean energy generation. New cationic (positively charged) polymer membranes are synthesized using appropriate controlled polymerization techniques. Their chemical, electrochemical, and mechanical stability are assessed under fuel cell operating conditions. One of the main objectives of this work is to make durable membranes which can withstand the harsh chemical environments of a fuel cell device. If successful, fuel cells with these newly synthesized polymer membranes will not rely on precious metals for energy generation, which represents a significant economic advantage. Students from diverse backgrounds are trained and involved in this project. A "Fuel Cell Project" with educational material and demonstrations is being developed. The project is made available on the web and used to educate junior high school students about renewable energy life cycles. In this project, the PIs are exploring the chemical and electrochemical stability of cationic polymers in the presence of hydroxide ions. The information obtained is used to build robust membranes for ion-transport in fuel cells. While transport of protons under acidic conditions is well established, hydroxide transport in solid polymer electrolytes under thermal and electrochemical stress is still a significant challenge. The development of next-generation robust, long-lasting and inert cationic materials for shuttling these caustic anions requires a combination of synthesis and characterization. Controlled polymerization techniques are critical for building the polymer materials. A battery of characterization techniques is used to evaluate their structure, stability and morphology. Specifically, X-ray scattering, atomic force microscopy, transport/device measurements and computational chemistry are used to probe the properties of these membranes. Transport and mechanical properties are tailored by synthesizing well-defined polymers and block copolymers. These materials are used to establish relationships between ion transport and morphology of novel ionomers. This work provides the basis for subsequent material design to optimize anion transport. If successful, the project will result in stable and efficient anion exchange membranes (AEMs) for alkaline fuel cells that do not need precious metals for proper function.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.