| Popis: |
The design of anion-exchange membranes, or AEMs, has attracted a great deal of attention in recent years due to the potential value of AEMs for anion transport in electrochemical energy systems. Anion-exchange membranes are polyelectrolytes made by covalently tethering positively charged groups to a polymer backbone, generally for the purpose of promoting hydroxide transport. Questions surrounding the improvement of hydroxide transport and the long-term stability of these materials under caustic conditions drive research in this field. Understanding the decomposition pathways of the tethered cation is crucial for constructing AEMs with high durability, making the design of model compounds and degradation experiments a necessity. The synthesis of monomers based on norbornene makes well-controlled polymerization methods like ring-opening metathesis polymerization (ROMP) and vinyl addition polymerization accessible. In turn, good control of the polymerization reaction allows for predictable polymer molecular weights and narrow molecular weight distributions, control over polymer composition, chain-end fidelity, and access to unique polymer architectures. The many possibilities in polymer and cationic structures have enormous influence over the properties and alkaline stability of the resulting anion-exchange material. The following dissertation details our efforts to synthesize and elucidate the degradation pathways of main group cations made from sulfur and phosphorus, as well as incorporate these cations into well-defined polymers. |
