Doctor of Philosophy
Ragogna, Paul J.
Gillies, Elizabeth R.
The content of this thesis focuses on the incorporation of phosphorus into amphiphilic block copolymers (BCPs) for the realization of novel properties in the solution phase self-assembled materials derived from the BCPs. The incorporation was achieved through either attaching phosphorus to the terminus of already existing BCPs or the synthesis of novel BCPs from prepared or commercially available phosphorus containing monomers. The phosphorus containing polymers exhibited properties dependent on the existence of the phosphorus species in the BCPs. The first example of this is the modification of poly(ethylene oxide)-b-poly(ε-caprolactone) (PEO-b-PCL) copolymers by the attachment of tetraalkyl phosphonium salts with varying alkyl chains to the PEO chain end. The resulting nanoscale assemblies displayed antibacterial activity against Escherichia coli and Staphylococcus aureus. The nano-assemblies were also able to encapsulate and release the hydrophobic drug tetracycline. The second example from this work is the incorporation of phosphorus into the side chains of an amphiphilic polystyrene-b-poly((4-vinylbenzyl)tributylphosphonium) (PS-b-P(P+X-)) BCP. The BCP was used to study the effect the counter-ion (X-) had on the aqueous self-assembly of the material through variation of the anion on the monomer. Anions investigated in the work included chloride, bromide, nitrate and trifluoromethylsulfonate. The work demonstrated that while maintaining the same degree of polymerization the change in the anion prior to self-assembly resulted in a significant difference in the resulting nanoparticles. The third example of the incorporation of phosphorus into a BCP features a poly(4-diphenylphosphino styrene)-b-poly((4-vinylbenzyl)tributylphosphonium chloride). This block copolymer features phosphorus in the P(III) and the P(V) oxidation states. The P(III) block is able to form the core of self-assembled nano-particles and was shown to coordinate Pd, W and Mo. The corona is able to undergo salt metathesis to coordinate AuCl4-. The final work presented in this thesis demonstrates efforts toward the synthesis of functional end-group containing polymers by the inclusion of phosphorus in RAFT agents. The work demonstrates the incorporation of a phosphonium salt onto the end-group of poly(butyl acrylate) polymers, and demonstrates that the presence of the phosphonium salt allows the material to self-assemble in aqueous solution.
Hisey, Benjamin F., "The Incorporation of Phosphorus into Block Copolymers and Their Self-Assembly" (2018). Electronic Thesis and Dissertation Repository. 5432.