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Title: Exploring the design, synthesis and function of novel block copolymer systems prepared via RAFT polymerisation
Author: Martin, Liam Thomas
ISNI:       0000 0004 7224 0863
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2017
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The work in this thesis includes aspects of RAFT polymerisation, block copolymer synthesis and their applications. Firstly, the development of one-pot multiblock copolymer synthesis using an ambient temperature process is described. The motivation for implementing this approach at reduced temperature was to accommodate for temperature sensitive monomers, namely acrylates. Using a redox initiator for aqueous RAFT polymerisation at room temperature, the opportunities and limitations of this synthetic approach are demonstrated through the preparation of a range of multiblock copolymers. Following this, the application of redox initiators in aqueous RAFT polymerisation is considered in more detail. The choice of redox initiating pair and the ratio of oxidising agent to reducing agent employed can have a strong influence of the rate of initiation, and hence polymerisation. In addition, the opportunity to prepare well-defined polymer extremely rapidly (full monomer conversion in ≈ 15 mins) with only moderate polymerisation temperatures (50 °C) using redox initiation is demonstrated. Finally, the role of reducing agent and polymerisation set-up on the ability to conduct RAFT in the presence of oxygen is assessed. The next chapter explores possible applications of multiblock copolymers with a focus on biological function. The preparation of guanidinium-rich polymers via RAFT polymerisation and their subsequent efficiency for cellular uptake is described. Using a guanidinium-functional acrylamide monomer, well-defined homopolymers are synthesised and their cell uptake efficiency assessed by comparison with analogous polyArginines. Following this, relatively low molar mass (< 6000 g.mol-1) cationic copolymers were prepared via RAFT polymerisation, incorporating a less hydrophilic comonomer, and the influence of both comonomer type and monomer distribution (statistical vs tetrablock vs diblock) on cellular uptake was investigated, to highlight the properties of multiblock copolymers. The final experimental chapter entails an alternative approach to block copolymer design, through the combination of two polymerisation techniques. A highly novel amphiphilic block copolymer composition containing poly(dimethylsiloxane) (PDMS) as a hydrophobic block and glycopolymer as a hydrophilic block was designed. The new copolymer composition was prepared using a PDMS-based macroCTA and a post-polymerisation modification approach and the self-assembly behaviour demonstrated on both a nano- and micron-scale using different self-assembly processes. This work was done with the motivation to generate fluid and robust giant glycosylated polymersomes which can interact with bacteria through carbohydrate-lectin binding, as a primitive synthetic cell mimic. The behaviour of the giant glycosylated polymersomes in the presence of bacteria was modulated through the incorporation of carbohydrates with differing affinities for the cell-surface proteins (lectins) of the bacteria.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry