Synthetic strategies towards ether-free polymeric hydroxide conducting membranes

The only way to combat the depletion of resources and climate crisis is to reduceour dependence on fossil fuels. Renewable sources, such as wind and solar energy,are increasingly used to meet our ever-growing energy demands; however, they areintermittent. One promising solution to the power crisis in the world is fuel cells,which, unlike the combustion engine, can operate on renewable fuels such ashydrogen, methanol, and ethanol without emitting pollutants with high efficiency.A conventional type of polymer electrolyte fuel cell is proton exchange fuel cells(PEMFCs), which have already moved from laboratory to market; however, theusage of Pt catalyst makes them costly and unstable. On the other hand, the fuelcells operating in alkaline media, anion exchange membrane fuel cells (AEMFCs)can use nonprecious-metal catalysts with higher redox reaction kinetics. However,the technology of AEMFCs is currently less developed than that of PEMFCs due toseveral challenges, including the need for high-performing anion exchangemembranes (AEMs) that can meet all requirements. The two main challengeshampering the development of AEMs for fuel cells are the lower conductivity ofPEMs and the lower thermochemical stability in alkaline media. It is worth notingthat research efforts now focus on obtaining stable polymer AEMs with highefficiency and low degradation in alkaline media.This thesis aims to investigate different structural factors, including polymerbackbone, and the design and placement of cationic moieties on the final propertiesof AEMs. Several ether-free polymers were synthesized through superacidmediatedpolyhydroxyalkylation reactions and, after required functionalization,were conducted to make fully quaternized polymers. AEMs were prepared from thepolymers and investigated in terms of water uptake, ion conductivity, thermalproperties, morphology, and alkaline stability.