Design and synthesis of functionalised polyethers and polyesters

Abstract

Artificial photosynthesis, a game changer in the field of alternative energy, is believed to be able to provide greener hydrogen in near future for hydrogen powered vehicles via the photocatalytic splitting of water. The Nafion membrane that is currently being widely used in water splitting systems has a number of flaws including its selectivity, environmental inadaptability, the need to be moistened to conduct protons and swelling. With membranes playing an important role, the development of new membranes having improved properties would bring about change in efficiency of the water splitting device. This thesis covers two different approaches in membrane design and synthesis in an attempt to achieve an ideal polymer. Chapter 1 gives an overview of the research area and objectives, starting from an introduction to the field of artificial photosynthesis with emphasis on photocatalytic water splitting and how the development of new membranes in place of Nafion could be beneficial for the field. Chapter 2 starts off with the synthesis and characterisation of four pyrene-based polyethers (AP Series) and two clickable-pyrene-based polyethers (YC Series). Two different methods have been employed for the synthesis of these polymers with one being more favorable than the other. The two approaches and their pros and cons will be discussed. Chapter 3 discusses the synthesis and characterisation of a successfully clicked pyrene derivative (Pyr2COOMe) and its potential polymerisation blueprint. Chapter 4 begins with the synthesis and characterisation of six anthracenebased polyethers (PA Series) with varying degree of modifications and two tapered-anthracene-co-modified polyethers (URV Series). Membranes of URV Series were prepared via immersion precipitation and their surface morphologies were studied. Chapter 5 highlights the synthesis, characterisation and coordination studies of a crown ether terephthalate derivative (CM1). The resemblance of its crystal XRD structure to an actual jellyfish will be shared. iv Chapter 6 discusses the synthesis and characterisation of three terephthalatebased polyesters. One of the polyesters was synthesised from CM1 monomer mentioned in Chapter 5. Apart from Chapter 1, every other chapter has been written in the format of a paper with their respective introduction and conclusion. Lastly, Chapter 7 includes a summary of each chapter in addition to a list of possible future work